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Ismaturrahmi, Ismaturrahmi, Hasanuddin Hasanuddin, and Agam Ihsan Hereri. "Teknik pematahan dormansi secara fisik dan kimia terhadap viabilitas benih aren (Arenga pinnata Merr.)." Jurnal Ilmiah Mahasiswa Pertanian 3, no. 4 (2018): 105–12. http://dx.doi.org/10.17969/jimfp.v3i4.9211.
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Abstrak. Penelitian ini bertujuan untuk mengetahui pengaruh teknik pematahan dormansi secara fisik dan kimia, serta nyata tidaknya interaksi antara pematahan dormansi secara fisik dengan pematahan dormansi secara kimia terhadap viabilitas benih aren. Penelitian ini dilaksanakan di Laboratorium Ilmu dan teknologi Benih, Fakultas Pertanian, Universitas Syiah Kuala, Darussalam, Banda Aceh, dari bulan juli sampai November 2017. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) Pola Faktorial 4 x 4 dengan 3 ulangan. Penelitian ini menggunakan 2 faktor yaitu: pematahan dormansi secara fisik (S), meliputi : (S0) = Tanpa perlakuan fisik, (S1) = Digosok dengan kertas amplas , (S2) = Digores dengan cutter sepanjang punggung benih, dan (S3) = Menghilangkan selaput gabus pada hilum, dan pematahan dormansi secara kimia (K), meliputi: (K0) = Konsentrasi 0% KNO3, (K1) = Konsentrasi 0,3% KNO3, (K2) = Konsentrasi 0,5% KNO3, (K3) = Konsentrasi 0,7% KNO3.Hasil penelitian yang telah dilakukan, dapat diambil kesimpulan bahwa : Kombinasi perlakuan secara fisik yang digores dengan cutter (S2) dengan konsentrasi KNO3 0,5% (K2) merupakan kombinasi perlakuan terbaik untuk pematahan dormanis pada benih aren.Dormancy Breaking Technique by Physical and Chemical Means on Viabitity of Palm Seed (Arenga pinnata Merr.)Abstract. This research aims to know the effect of physics and chemical dormancy breaking technique, and significant or not the interaction between physical dormancy breaking with chemical dormancy breaking on the viability of the palm seeds. This research was conducted in Science and Seed Technology Laboratory, Faculty of Agriculture, Syiah Kuala University, Darussalam, Banda Aceh, from July to November 2017. This research used Factorial Completely Randomize Design with 4 x 4 repeated 3 times. This research uses 2 factors, namely: physical dormancy breaking (S), including: (S0) = Without physical treatment, (S1) = Rubbed with sandpaper, (S2) = scratched with cutter along the back of seed, and (S3) = Eliminate the cork membrane on the hylum, and chemical dormancy breaking (K), namely: (K0) = Concentration 0% KNO3, (K1) = Concentration 0.3% KNO3, (K2) = Concentration 0.5% KNO3, (K3) = Concentration 0.7% KNO3. The results of research that has been done, it can be concluded that : The combination of physical treatment scratched with cutter (S2) with KNO3 concentration of 0.5% (K2) is the best treatment combination for dormanic breaking of palm seeds.
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Kissing Kucek, L., M. D. Azevedo, S. S. Eagen, et al. "Seed Dormancy in Hairy Vetch (Vicia villosa Roth) Is Influenced by Genotype and Environment." Agronomy 10, no. 11 (2020): 1804. http://dx.doi.org/10.3390/agronomy10111804.
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Seed dormancy complicates the agricultural use of many legume species. Understanding the genetic and environmental drivers of seed dormancy is necessary for advancing crop improvement for legumes, such as Vicia villosa. In this study, we quantify the magnitude of genetic and environmental effects on physical dormancy among 1488 maternal V. villosa plants from 18 diverse environments. Furthermore, we explore the relationship between physical dormancy and environmental conditions during seed development. Additive genetic variance (h2) accounted for 40% of the variance, while the growing environment explained 28% of the variance in physical dormancy. Maternal lines showed complete variance in physical dormancy, as one line was 100% dormant, and 56 lines were 0% dormant. Distributions of physical dormancy varied widely among seed production environments, with some site-years strongly skewed toward physically dormant seed, while other site-years exhibited little dormant seed. Twenty-three weather variables were associated with environmental and error effects of physical dormancy. High mean and minimum relative humidity, low mean and maximum temperature, and high precipitation weakly grouped with low physical dormancy. Weather variables calculated from fixed time windows approximating seed maturity to seed harvest at each site-year tended to be less predictive than biological seed drying windows calculated based on seed maturity of each maternal line. Overall, individual and cumulative effects of weather variables were poor predictors of physical dormancy. Moderate heritability indicates that breeding programs can select against physical dormancy and improve V. villosa for agricultural use. Marker-based approaches would maximize selection for physical dormancy by reducing the influence of unpredictable environmental effects.
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Liu, Wenjie, Antal H. Kovacs, and Jinqiang Hou. "Cancer Cells in Sleep Mode: Wake Them to Eliminate or Keep Them Asleep Forever?" Cells 13, no. 23 (2024): 2022. https://doi.org/10.3390/cells13232022.
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Cancer cell dormancy is a critical phase in cancer development, wherein cancer cells exist in a latent state marked by temporary but reversible growth arrest. This dormancy phase contributes to anticancer drug resistance, cancer recurrence, and metastasis. Treatment strategies aimed at cancer dormancy can be categorized into two contradictory approaches: inducing cancer cells into a dormant state or eliminating dormant cells. While the former seeks to establish permanent dormancy, the latter aims at eradicating this small population of dormant cells. In this review, we explore the current advancements in therapeutic methods targeting cancer cell dormancy and discuss future strategies. The concept of cancer cell dormancy has emerged as a promising avenue for novel cancer treatments, holding the potential for breakthroughs in the future.
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Haile, Teketel A., and Steven J. Shirtliffe. "Effect of Harvest Timing on Dormancy Induction in Canola Seeds." Weed Science 62, no. 3 (2014): 548–54. http://dx.doi.org/10.1614/ws-d-13-00178.1.
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Seedbank persistence in canola seeds is related to their potential to develop secondary dormancy. This can result in volunteer weed problems many years after canola production. The potential to be induced into secondary dormancy is controlled by both the canola genetics and the environment of the mother plant. However, the effect of time of harvesting on secondary dormancy potential is not known. The objective of this study was to determine the effect of harvest timing on potential to develop seed dormancy in canola. Six harvest samples were collected weekly from two canola genotypes (5440 and 5020) starting from 10 to 20% seed color change on the main stem until they were fully ripened. Freshly harvested seeds of 5440 and 5020 showed 13 and 16% primary dormancy at 32 and 33 d after flowering (DAF), respectively, but dormancy decreased with harvest timings and no dormancy was observed when seeds were fully mature (78 DAF). After dormancy induction, 10% of 5440 seeds were dormant at 32 DAF, but 94% of seeds were dormant at 78 DAF. Similarly, 70% of 5020 seeds were dormant at 33 DAF, but 90% of seeds were dormant at 68 DAF. Thus, seeds had lower potential to secondary dormancy at early development but have a high potential to secondary dormancy induction at full maturity. This study suggests that windrowing these canola genotypes at the recommended time (60% seed color change on the main stem) may reduce ability of the seed to develop secondary dormancy and thus reduce the persistence of seeds in the soil seedbank.
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Hasimi, Muhammad Hasbi, Eva Agustina, Nur Yohaniz Miskiah, Muhammad Ihsan Fadhiel, Nadia Nadia, and Gani Jawak. "Pematahan dormansi benih cabai lokal tiung tanjung asal tabalong Kalimantan Selatan." Jurnal AGRO 11, no. 1 (2024): 133–46. http://dx.doi.org/10.15575/35866.
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Tiung Tanjung seeds pepper are believed to have dormant properties that can be detrimental to farmers during planting. The aim of this study was to find out the correct method of breaking the dormancy on Tiung Tanjung pepper. The study was designed with a two-stage nested design, the first stage was the seed storage time of 1, 3, 5, 7, 9, and 11 weeks. The second stage was a dormant breakdown method consisting of 8 treatments namely control, aquades, warm water (40 °C), ionic water, IAA 100 ppm, IAA 200 ppm, KNO3 0,1% and KNO3 0.5%. Each unit of experiment used 3 repetitions with 25 seeds planted using Top of Paper method (TP). Parameters observed were the vigor index, growth speed, germination,maximum germination potential, fresh seed, seed mortality rate, and growth performance. The results of the study showed that the treatment of Tiung pepper seed immersed in 0.5% KNO3 for 24 hours was able to break the dormancy at 7 weeks after storage with germination values increased to 80%. Treatment with 0.1% KNO3 could break the dormancy in the 9th week. Dormancy breakdown treatments with aquades, warm water (40 °C), ionic water, IAA 100 ppm, and IAA 200 ppm had not been able to break the dormancy of Tiung pepper seeds up to 11 weeks of storage. Benih cabai Tiung Tanjung diyakini memiliki sifat dormansi yang dapat merugikan petani saat penanaman. Tujuan dari penelitian ini adalah untuk mengetahui metode pematahan dormansi yang tepat pada cabai Tiung Tanjung. Penelitian dilaksanakan dengan rancangan tersarang dua tingkat, tingkat pertama adalah lama masa simpan benih yaitu 1, 3, 5, 7, 9, dan 11 minggu simpan dan tingkat kedua adalah metode pematahan dormansi yang terdiri dari 8 perlakuan yaitu kontrol, akuades, air hangat (40 °C), air ion, IAA 100 ppm, IAA 200 ppm, KNO3 0,1% dan KNO3 0,5%. Setiap satuan percobaan menggunakan 3 ulangan. Setiap ulangan menggunakan 25 benih yang ditanam dengan metode uji di atas kertas (UDK). Parameter yang diamati adalah indeks vigor, kecepatan tumbuh, daya berkecambah, potensi tumbuh maksimum, benih segar tidak tumbuh, dan tingkat kematian benih, dan performa kecambah. Hasil penelitian menunjukkan bahwa perlakuan perendaman benih cabai Tiung dalam KNO3 0,5% selama 24 jam mampu mematahkan dormansi pada 7 minggu setelah simpan dengan nilai daya berkecambah mencapai 80%. Perlakuan dengan KNO3 0,1% dapat mematahkan dormansi pada minggu ke-9. Perlakuan pematahan dormansi dengan akuades, air hangat (40 °C), air ion, IAA 100 ppm dan IAA 200 ppm belum mampu mematahkan dormansi benih cabai Tiung hingga 11 minggu simpan.
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Kehl, Kassiana, Ivan Carvalho, Deivid Sacon, et al. "Characterization of Brazilian black oat genotypes regarding seed dormancy." DELOS: DESARROLLO LOCAL SOSTENIBLE 16, no. 48 (2023): 3337–53. http://dx.doi.org/10.55905/rdelosv16.n48-023.
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The objective of this work was to characterize 30 black oat genotypes regarding seed dormancy. The experiment was carried out in the 2018 and 2019 seasons in a completely randomized design with three factors, being 30 black oat genotypes, two methods of seed germination analysis (with and without dormancy breaking) and five evaluation periods (0, 30, 60, 90 and 120 days after harvest), distributed in four replicates. In each postharvest period, the variables: normal seedlings, abnormal seedlings, number of dormant seeds and number of dead seeds were analyzed. There was significant interaction between factors during the two years of experimentation. In the 2018 season, the percentage of dormant seeds at period zero ranged from 47 to 3% in the method with overcoming dormancy, 86 to 33% in the method without overcoming dormancy. The genotypes ALPHA 1629 and IAPAR 61- Ibiporã presented highest dormancy. In the 2019 season, the percentage of dormant seeds at period zero ranged from 56 to 3% with overcoming dormancy and 85 to 12% without overcoming dormancy. There is variability of dormancy among genotypes and this is overcome after 60 days of harvest. The IAPAR 61-Ibiporã genotype have highest of dormancy seeds.
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Qaderi, Mirwais M. "Environmental Regulation of Weed Seed Dormancy and Germination." Seeds 2, no. 3 (2023): 259–77. http://dx.doi.org/10.3390/seeds2030020.
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Many weeds produce dormant seeds that are unable to complete germination under favourable conditions. There are two types of seed dormancy: primary dormancy (innate dormancy), in which seeds are in a dormant state upon release from the parent plant, and secondary dormancy (induced dormancy), in which dormancy develops in seeds through some experience after release from the parent plant. Mechanisms of seed dormancy are categorized as embryo dormancy and coat-imposed dormancy. In embryo dormancy, the control of dormancy resides within the embryo itself, and in coat-imposed dormancy, it is maintained by the structures enclosing the embryo. Many factors can influence seed dormancy during development and after dispersal; they can be abiotic, biotic, or a combination of both. Most weeds deposit a large number of seeds in the seed bank, which can be one of two types—transient or persistent. In the transient type, all viable seeds in the soil germinate or die within one year, and there is no carry-over until a new crop is deposited. In the persistent type, at least some seeds survive in the soil for more than one year and there is always some carry-over until a new crop is deposited. Some dormant seeds require after-ripening—changes in dry seeds that cause or improve germination. Nondormant, viable seeds can germinate if they encounter appropriate conditions. In the face of climate change, including global warming, some weeds produce a large proportion of nondormant seeds, which germinate shortly after dispersal, and a smaller, more transient seed bank. Further studies are required to explore this phenomenon.
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Tseng, Te-Ming, Vinod K. Shivrain, Amy Lawton-Rauh, and Nilda R. Burgos. "Dormancy-linked Population Structure of Weedy Rice (Oryza sp.)." Weed Science 66, no. 3 (2018): 331–39. http://dx.doi.org/10.1017/wsc.2017.86.
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AbstractSeed dormancy allows weedy rice (Oryza sp.) to persist in rice production systems. Weedy and wild relatives of rice (Oryza sativa L.) exhibit different levels of dormancy, which allows them to escape weed management tactics, increasing the potential for flowering synchronization, and therefore gene flow, between weedy Oryza sp. and cultivated rice. In this study, we determined the genetic diversity and divergence of representative dormant and nondormant weedy Oryza sp. groups from Arkansas. Twenty-five simple sequence repeat markers closely associated with seed dormancy were used. Four populations were included: dormant blackhull, dormant strawhull, nondormant blackhull, and nondormant strawhull. The overall gene diversity was 0.355, indicating considerable genetic variation among populations in these dormancy-related loci. Gene diversity among blackhull populations (0.398) was higher than among strawhull populations (0.245). Higher genetic diversity was also observed within and among dormant populations than in nondormant populations. Cluster analysis of 16 accessions, based on Nei’s genetic distance, showed four clusters. Clusters I, III, and IV consisted of only blackhull accessions, whereas Cluster II comprised only strawhull accessions. These four clusters did not separate cleanly into dormant and nondormant populations, indicating that not all markers were tightly linked to dormancy. The strawhull groups were most distant from blackhull weedy Oryza sp. groups. These data indicate complex genetic control of the dormancy trait, as dormant individuals exhibited higher genetic diversity than nondormant individuals. Seed-dormancy trait contributes to population structure of weedy Oryza sp., but this influence is less than that of hull color. Markers unique to the dormant populations are good candidates for follow-up studies on the control of seed dormancy in weedy Oryza sp.
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Buijs, Gonda. "A Perspective on Secondary Seed Dormancy in Arabidopsis thaliana." Plants 9, no. 6 (2020): 749. http://dx.doi.org/10.3390/plants9060749.
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Primary seed dormancy is the phenomenon whereby seeds newly shed by the mother plant are unable to germinate under otherwise favorable conditions for germination. Primary dormancy is released during dry seed storage (after-ripening), and the seeds acquire the capacity to germinate upon imbibition under favorable conditions, i.e., they become non-dormant. Primary dormancy can also be released from the seed by various treatments, for example, by cold imbibition (stratification). Non-dormant seeds can temporarily block their germination if exposed to unfavorable conditions upon seed imbibition until favorable conditions are available. Nevertheless, prolonged unfavorable conditions will re-induce dormancy, i.e., germination will be blocked upon exposure to favorable conditions. This phenomenon is referred to as secondary dormancy. Relative to primary dormancy, the mechanisms underlying secondary dormancy remain understudied in Arabidopsis thaliana and largely unknown. This is partly due to the experimental difficulty in observing secondary dormancy in the laboratory and the absence of established experimental protocols. Here, an overview is provided of the current knowledge on secondary dormancy focusing on A. thaliana, and a working model describing secondary dormancy is proposed, focusing on the interaction of primary and secondary dormancy.
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Seshu, D. V., and M. Dadlani. "Mechanism of seed dormancy in rice." Seed Science Research 1, no. 3 (1991): 187–94. http://dx.doi.org/10.1017/s0960258500000854.
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AbstractDormancy in rice (Oryza sativa L.) seed is imposed by certain physical and chemical factors associated with its covering structures, i.e.hull and pericarp. The nature of these germination blocks, their mode ofaction, and processes regulating the release of dormancy are not fully understood. Of nine rice cultivars studied, Ching-shi 15, Stejaree 45, PTB10, and Mahsuri are weakly dormant, and Bansphul, Benaful, Kataktara, Dular, and N22 are dormant. Release of seed dormancy in rice by various treatments, oxidative processes and enzymic changes associated with dormancy, and parallelism between natural and artificially imposed dormancy patterns were examined. The influence of the hull in imposing dormancy was stronger and more prolonged than that of the pericarp. Application of GA3 was effective in inducing germination only in weakly dormant cultivars. Dormancy was completely released in all cultivars by subjecting the seeds to moist heat treatment, by removing the hull and pericarp, and by applying GA3 after dehulling. Dormant cultivars had higher O2 uptake rate and peroxidase activity and lower amylase and dehydrogenase activities than the weakly dormant ones. Hull removal substantially decreased peroxidase activity but enhanced amylase and dehydrogenase activities. Nonanoic acid (C90), a short-chain saturated fatty acid (SCSFA), when exogenously applied to non-dormant seeds imposed dormancy. Dry heat treatment or presoaking in 0.01 m KNO3 or 0.1 m H2O2 was very effective in releasing SCSFA-imposed dormancy. Amylase activity was greatly reduced by treatments with nonanoic acid (C90) or ABA. Considering earlier reports and results of the present study, it is proposed that seed dormancy in rice is regulated both by the presence of SCSFAs and ABA in the hull and the pericarp. The relative significance of these substances in cultivars of tropical and temperate origins and its implications in terms of ecogeographic adaptability are discussed.
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Faust, Miklos. "Use of Hormones and Growth Regulators in Quantifying Bud Dormancy." HortScience 30, no. 4 (1995): 908C—908. http://dx.doi.org/10.21273/hortsci.30.4.908c.
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At the beginning and near to the end of the endodormant period, cytokinin-type growth regulators are effective to end dormancy in apple. The same growth regulators are not effective during the middle of this period. Terminal buds require less chilling than lateral buds to emerge from the dormant period. Lateral buds on decapitated shoots also require less chilling, indicating that auxin may be involved in dormancy. Replacing the terminal with IAA keeps water in bound state in the lateral buds, indicating the effect of IAA in dormancy. We have developed the theory that the beginning and the end of the winter-dormant period is governed by apical dominance. It appears that only this period can be manipulated either with dormancy avoidance methods or with dormancy-breaking chemicals. The central portion of the dormant period is not subject to manipulation. Therefore, it is important that the depth of the dormancy is quantified. Certain growth regulators can be used for determining the state of bud dormancy. Thidiazuron gives results within 2 to 4 days.
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Soltani, Elias, Sabine Gruber, Mostafa Oveisi, Nader Salehi, Iraj Alahdadi, and Majid Ghorbani Javid. "Water stress, temperature regimes and light control induction, and loss of secondary dormancy in Brassica napus L. seeds." Seed Science Research 27, no. 3 (2017): 217–30. http://dx.doi.org/10.1017/s0960258517000186.
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AbstractThis study investigated the induction and loss of dormancy in oilseed rape (Brassica napus). Twenty genotypes were preliminary screened; from these, two genotypes, RGS003 and Hayola 308, which possess high potential for dormancy induction (HSD) and medium potential to induce secondary dormancy (MSD), were selected. The stratification of seeds at alternating temperatures of 5–30°C (in dark) significantly relieved secondary dormancy, but dormancy was not fully released. The ψb(50) values were −1.05 and −1.06 MPa for the MSD and the HSD before dormancy induction. After inducing dormancy, the ψb(50) values for the MSD and the HSD were increased to −0.59 and −0.01 on day 0 stratification at 20°C. The hydrothermal time (θHT) value was low for one-day stratification for HSD in comparison with other stratification treatments. Water stress can induce dormancy (if the seeds have the genetic potential for secondary dormancy) and warm stratification (in dark) can only reduce the intensity of dormancy. The seeds with a high potential of dormancy induction can overcome dormancy at alternating temperatures and in the presence of light. It can, therefore, be concluded that a portion of seeds can enter the cycle of dormancy ↔ non-dormancy. The secondary dormant seeds of B. napus cannot become non-dormant in darkness, but the level of dormancy may change from maximum (after water stress) to minimum (after warm stratification). It seems that the dormancy imposed by the conditions of deep burial (darkness in combination with water stress and more constant temperatures) might be more important to seed persistence than secondary dormancy induction and release. The dormancy cycle is an important pre-requisite in order to sense the depth of burial and the best time for seed germination.
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Pawłowski, Tomasz A., Barbara Bujarska-Borkowska, Jan Suszka, et al. "Temperature Regulation of Primary and Secondary Seed Dormancy in Rosa canina L.: Findings from Proteomic Analysis." International Journal of Molecular Sciences 21, no. 19 (2020): 7008. http://dx.doi.org/10.3390/ijms21197008.
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Temperature is a key environmental factor restricting seed germination. Rose (Rosa canina L.) seeds are characterized by physical/physiological dormancy, which is broken during warm, followed by cold stratification. Exposing pretreated seeds to 20 °C resulted in the induction of secondary dormancy. The aim of this study was to identify and functionally characterize the proteins associated with dormancy control of rose seeds. Proteins from primary dormant, after warm and cold stratification (nondormant), and secondary dormant seeds were analyzed using 2-D electrophoresis. Proteins that varied in abundance were identified by mass spectrometry. Results showed that cold stratifications affected the variability of the highest number of spots, and there were more common spots with secondary dormancy than with warm stratification. The increase of mitochondrial proteins and actin during dormancy breaking suggests changes in cell functioning and seed preparation to germination. Secondary dormant seeds were characterized by low levels of legumin, metabolic enzymes, and actin, suggesting the consumption of storage materials, a decrease in metabolic activity, and cell elongation. Breaking the dormancy of rose seeds increased the abundance of cellular and metabolic proteins that promote germination. Induction of secondary dormancy caused a decrease in these proteins and germination arrest.
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Aqbi, Hussein F., Savannah E. Butler, Rebecca Keim, Michael O. Idowu, and Masoud H. Manjili. "Chemotherapy-induced tumor dormancy and relapse." Journal of Immunology 198, no. 1_Supplement (2017): 204.7. http://dx.doi.org/10.4049/jimmunol.198.supp.204.7.
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Abstract Breast cancer mortality is due to distant recurrence of the disease as a result of awakening dormant tumor cells that were established by cancer therapies. The mechanisms through which dormant tumor cells are maintained or escape from dormancy, and relapse remain elusive. One such mechanism that may play a role in tumor dormancy maintenance or escape is autophagy; a process important in all cells for the removal of damaged proteins and organelles. Although autophagy is a mechanism of tumor suppression, it also confers stress tolerance that enables tumor cells to survive under adverse conditions. Here, we wanted to determine the role of autophagy in tumor dormancy and sensitivity of dormant tumor cells to immunotherapy, i.e., IFN-gamma treatment. A mouse mammary carcinoma (MMC) cell line was established from the neu over-expressing FVBN202 transgenic mouse. We also used Adriamycin (ADR) for the establishment of chemotherapy-induced tumor dormancy, and blocked autophagy by chloroquine (CQ). We demonstrated that a transient blockade of autophagy by CQ during ADR treatment prolonged tumor dormancy, in vitro, but not in vivo. Also, we determined that dormant tumor cells established by ADR or ADR+CQ were more sensitive to IFN-gamma induced apoptosis compared with non-dormant, proliferating tumor cells. These observations suggest that autophagy could participate, in part, in tumor dormancy without affecting the sensitivity of dormant cells to IFN-gamma treatment.
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Bolingue, William, Benoit Ly Vu, Olivier Leprince, and Julia Buitink. "Characterization of dormancy behaviour in seeds of the model legume Medicago truncatula." Seed Science Research 20, no. 2 (2010): 97–107. http://dx.doi.org/10.1017/s0960258510000061.
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AbstractSeeds of Medicago truncatula, a genomic model species for legumes, exhibit physiological and physical dormancy. Here, the factors influencing the germination behaviour of freshly harvested and stored seeds were investigated using several genotypes. Hardseededness is promoted when mature seeds are equilibrated at relative humidities (RH) below 75%. The release of physical dormancy during imbibition was dependent on the initial water content/RH that the seeds were dried to: the drier the seeds, the longer the imbibition time needed to break physical dormancy. The kinetics of physical dormancy release was slower than that of physiological dormancy, making it possible to uncouple both phenomena. Freshly harvested embryos without seed coverings germinated at the same speed as afterripened seeds. The depth of dormancy varied between different M. truncatula genotypes, from more to less dormant: DZA315.16>A17 (Jemalong)>R108>DZA45.5. This difference was eliminated by removing the endosperm. Collectively, these observations indicate that the endosperm is likely the main factor in the reduced germination of freshly harvested seeds. White light decreased germination speed of dormant seeds whereas it had no effect on non-dormant seeds. Recently harvested seeds were most dormant at temperatures above 17°C, whereas afterripened seeds germinated over a wider range of temperature. Fluridone could efficiently break dormancy, reinforcing the role of abscisic acid (ABA) synthesis. However, dormancy was not affected by gibberellic acid (100 μM GA3) or nitrate. The particular dormancy features unravelled here for M. truncatula, combined with the available genomic resources, make it a new, useful model for genetic and molecular studies which can complement those developed for Arabidopsis.
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Hawryzki, Allan R., Geraldine A. Allen, and Joseph A. Antos. "Prolonged dormancy in the geophyte Allium amplectens on Vancouver Island." Botany 89, no. 11 (2011): 737–44. http://dx.doi.org/10.1139/b11-057.
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Prolonged dormancy occurs when a plant fails to appear above ground during the growing season. Although it may be an important life history trait of many geophytes, studies focusing on prolonged dormancy are infrequent and are concentrated on the Orchidaceae even though the phenomenon occurs in many taxonomic groups. We tracked individual plants of Allium amplectens (Amaryllidaceae) in permanent plots on Vancouver Island, which allowed us to determine rates of prolonged dormancy during a 4-year period. Dormancy rates per year averaged 38% and differed substantially among years. Over 70% of plants had a dormant period during the study. Dormancy periods of 2 years were almost as frequent as 1-year periods, and 8% of plants were dormant for 3 years. Plant density, which included small plants that we could not track in the plots, varied much more among years than did dormancy of tracked plants, suggesting that small plants may be especially prone to dormancy. High rates of prolonged dormancy and frequent multiyear dormancy indicate that this is an important life history feature of A. amplectens. We suggest that prolonged dormancy contributes to the ability of this species, and probably other species, to persist in dry habitats with fluctuating resources.
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Copani, V., G. Testa, A. Lombardo, and S. L. Cosentino. "Evaluation of populations of Dactylis glomerata L. native to Mediterranean environments." Crop and Pasture Science 63, no. 12 (2012): 1124. http://dx.doi.org/10.1071/cp12276.
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Several morphological and agronomic traits and the genetic diversity of nine Dactylis glomerata L. populations collected throughout Sicily (semi-arid Mediterranean environment) were evaluated for two successive years. Significant differences were recorded for morphological traits (plant height, leaf length, leaf width). In relation to the measurement of summer dormancy, the results suggest the expression of different levels of dormancy (completely dormant, semi-dormant, and non-dormant). For biomass yield, some Sicilian populations (SD63 and SD56) characterised by low levels of summer dormancy show production levels similar to the summer-active control varieties (Medly and Porto). However, SD46, with a much higher level of dormancy, gave biomass yield higher than the summer-dormant control variety (Kasbah). The genetic diversity evaluated by fAFLP analysis confirms the observed morphological and agronomic variability.
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Esfandiari, Azadeh, Cara Norling, Ryohei Kaji, et al. "Variations in Seed Dormancy Occurrence and Their Classifications in Thirteen Actinidia Species." Seeds 3, no. 2 (2024): 179–96. http://dx.doi.org/10.3390/seeds3020014.
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As differences in seed dormancy between Actinidia species have not been reported previously, in this study we characterized the variation in the dormancy of seeds in 13 kiwifruit species that originated from different regions of China and Taiwan, and for which mature plants are now growing in New Zealand orchards. Dormancy-breaking treatments, including cold-moist stratification, seed coat scarification and soaking in water and gibberellic acid (GA3), were tested for their efficacy in alleviating dormancy and improving final germination and germination rates. In addition, we assessed seed viability using RNA integrity analysis to distinguish dead seeds from dormant seeds. This study identified that dormancy type in Actinidia seeds is species-specific and can be morphological, morphophysiological or a combination of physiological and physical, and that seed RNA integrity is a useful metric to incorporate into seed dormancy studies. Our results also suggest that species originating from colder climates that experience large differences between winter minimum and summer maximum temperatures exhibit physiological dormancy and require cold-moist stratification, contrasting with species originating in milder climates. Interestingly, although not all seeds from all the species were dormant, the proportion of dormant seeds in each species did not correlate to the climatic data of the region from which they originated. These findings provide new insights into mechanisms of seed dormancy in kiwifruit.
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Boon, Calvin, and Thomas Dick. "Mycobacterium bovis BCG Response Regulator Essential for Hypoxic Dormancy." Journal of Bacteriology 184, no. 24 (2002): 6760–67. http://dx.doi.org/10.1128/jb.184.24.6760-6767.2002.
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ABSTRACT Obligately aerobic tubercle bacilli are capable of adapting to survive hypoxia by developing into a nonreplicating or dormant form. Dormant bacilli maintain viability for extended periods. Furthermore, they are resistant to antimycobacterials, and hence, dormancy might play a role in the persistence of tuberculosis infection despite prolonged chemotherapy. Previously, we have grown dormant Mycobacterium bovis BCG in an oxygen-limited Wayne culture system and subjected the bacilli to proteome analysis. This work revealed the upregulation of the response regulator Rv3133c and three other polypeptides (α-crystallin and two “conserved hypothetical” proteins) upon entry into dormancy. Here, we replaced the coding sequence of the response regulator with a kanamycin resistance cassette and demonstrated that the loss-of-function mutant died after oxygen starvation-induced termination of growth. Thus, the disruption of this dormancy-induced transcription factor resulted in loss of the ability of BCG to adapt to survival of hypoxia. Two-dimensional gel electrophoresis of protein extracts from the gene-disrupted strain showed that the genetic loss of the response regulator caused loss of the induction of the other three dormancy proteins. Thus, the upregulation of these dormancy proteins requires the response regulator. Based on these two functions, dormancy survival and regulation, we named the Rv3133c gene dosR for dormancy survival regulator. Our results provide conclusive evidence that DosR is a key regulator in the oxygen starvation-induced mycobacterial dormancy response.
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Li, Bowen, Yichun Huang, Hui Ming, Edouard C. Nice, Rongrong Xuan, and Canhua Huang. "Redox Control of the Dormant Cancer Cell Life Cycle." Cells 10, no. 10 (2021): 2707. http://dx.doi.org/10.3390/cells10102707.
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Following efficient tumor therapy, some cancer cells may survive through a dormancy process, contributing to tumor recurrence and worse outcomes. Dormancy is considered a process where most cancer cells in a tumor cell population are quiescent with no, or only slow, proliferation. Recent advances indicate that redox mechanisms control the dormant cancer cell life cycle, including dormancy entrance, long-term dormancy, and metastatic relapse. This regulatory network is orchestrated mainly through redox modification on key regulators or global change of reactive oxygen species (ROS) levels in dormant cancer cells. Encouragingly, several strategies targeting redox signaling, including sleeping, awaking, or killing dormant cancer cells are currently under early clinical evaluation. However, the molecular mechanisms underlying redox control of the dormant cancer cell cycle are poorly understood and need further exploration. In this review, we discuss the underlying molecular basis of redox signaling in the cell life cycle of dormant cancer and the potential redox-based targeting strategies for eliminating dormant cancer cells.
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Leon, Ramon G., Diane C. Bassham, and Micheal D. K. Owen. "Inheritance of deep seed dormancy and stratification-mediated dormancy alleviation in Amaranthus tuberculatus." Seed Science Research 16, no. 3 (2006): 193–202. http://dx.doi.org/10.1079/ssr2006250.
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Amaranthus tuberculatusis a weed species that has shifted emergence patterns over the past few years, presumably due to changes in seed dormancy in response to selection in agricultural fields. Although it is recognized that the seed dormancy phenotype is greatly affected by the environment, it is also acknowledged that the genotype plays a significant role. However, the importance of the genotype in determining intra-population seed dormancy variability, and the effect on emergence patterns, is not well understood. The objective of the present study was to determine the importance of the genotype on deep dormancy and the stratification-mediated dormancy alleviation inA. tuberculatus. Wild populations differing in seed dormancy were crossed and F2families were generated. These families were used to determine narrow sense heritability of dormancy and stratification-mediated dormancy alleviation at the individual (hi2) and family (hf2) levels.hi2ranged from 0.13 to 0.4 and 0.04 to 0.06 for the dormancy and stratification response, respectively. In the case ofhf2, the values ranged from 0.76 to 0.91 for deep dormancy and from 0.33 to 0.58 for the stratification response. The genetic correlation between these two traits was below 0.075, indicating that different genes control them. High temperature strengthened the dormancy of deeply dormant seeds, making them less sensitive to stratification. However, high temperature promoted the germination of non-deeply dormant seeds. It is proposed that delayed weed emergence can be generated by selecting genes that control stratification response, and not necessarily only the genes that are directly responsible for deep dormancy.
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Fairey, D. T., N. A. Fairey, and L. P. Lefkovitch. "The relationship between fall dormancy and germplasm source in North American alfalfa cultivars." Canadian Journal of Plant Science 76, no. 3 (1996): 429–33. http://dx.doi.org/10.4141/cjps96-076.
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Most of the genetic diversity of North American alfalfa cultivars has been accounted for by nine germplasm sources listed in descending order of winter hardiness as follows: Medicago sativa ssp. falcata, Ladak, M. sativa ssp. xvaria, Turkistan, Flemish, Chilean, Peruvian, Indian and African. In most instances, the breeder assigns a fall dormancy score and the relative proportions of each of the nine germplasm source for each cultivar at registration. The fall dormancy score (1 = dormant to 9 = non-dormant), determined by measuring plant height in October after harvest in early September, is used to indicate cultivar adaptation for different regions. This study examines the relationship between germplasm composition and plant height, the equivalence of fall dormancy. The signs on the partial regression coefficients of a multiple regression analysis of plant height on the proportional content of the nine sources of germplasm showed that the fall dormancy fell essentially into two classes, namely, a dormant category, comprising cultivars containing a large contribution of Falcata and Ladak, and a non-dormant category, in which Indian and African germplasm predominate. This does not necessarily preclude the influence of any of the other germplasm sources on fall dormancy, since they represent a rich source of diversity. However, nine distinct classes were not recognisable, perhaps because of the lack of an exact equivalence between fall dormancy class and plant height of the fall regrowth. Since these observations have not been derived in a common nursery, the latitude and latitude × cultivar effects have been disregarded. These limitations should be recognized when using the currently assigned fall dormancy ratings to predict cultivar adaptation. Key words: Alfalfa, fall dormancy, sources of germplasm
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Thompson, Ken, Roberta M. Ceriani, Jan P. Bakker, and Renée M. Bekker. "Are seed dormancy and persistence in soil related?" Seed Science Research 13, no. 2 (2003): 97–100. http://dx.doi.org/10.1079/ssr2003128.
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AbstractThere is confusion in the ecological literature between seed dormancy and persistence in soil. Some ecologists seem to assume that dormancy is necessary for persistence, while others imply that dormancy and persistence are virtually synonymous. Here, we show that there is no close relationship between dormancy and persistence and, incidentally, that conventional methods of investigating soil seed banks underestimate the persistence of species with dormant seeds. The confusion appears to arise from the concept of ‘enforced dormancy’, which is not genuinely dormancy at all, and would be eliminated if ecologists adopted the definition of dormancy employed by physiologists. Dormancy is a characteristic of the seed, not of the environment, the degree of which defines the conditions required to make the seed germinate.
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Batlla, Diego, and Roberto L. Benech-Arnold. "A framework for the interpretation of temperature effects on dormancy and germination in seed populations showing dormancy." Seed Science Research 25, no. 2 (2015): 147–58. http://dx.doi.org/10.1017/s0960258514000452.
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AbstractTemperature is a key factor affecting both dormancy and germination. In non-dormant seeds, when temperature is within the thermal range permissive for germination, it just regulates germination velocity, while in seeds presenting dormancy it can also be affecting dormancy level, dormancy termination and the expression of dormancy itself. This dual effect of temperature on dormancy and germination often leads to misinterpretation of obtained germination results and confounds the analysis of temperature effects in seed populations presenting some degree of dormancy. In the present paper we discuss the effect of temperature in the regulation of dormancy level and its implications in dormancy expression, as an attempt to construct a conceptual framework that allows distinguishing between the effects of temperature on dormancy and germination. Finally, we present examples of how a better understanding of these effects could help us to interpret the mixed effects of temperature on both processes during incubation of seeds presenting dormancy.
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Ai, Jiaqi, Wuhong Wang, Tianhua Hu, et al. "Identification of Quantitative Trait Loci and Candidate Genes Controlling Seed Dormancy in Eggplant (Solanum melongena L.)." Genes 15, no. 4 (2024): 415. http://dx.doi.org/10.3390/genes15040415.
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Seed dormancy is a life adaptation trait exhibited by plants in response to environmental changes during their growth and development. The dormancy of commercial seeds is the key factor affecting seed quality. Eggplant seed dormancy is controlled by quantitative trait loci (QTLs), but reliable QTLs related to eggplant dormancy are still lacking. In this study, F2 populations obtained through the hybridization of paternally inbred lines with significant differences in dormancy were used to detect regulatory sites of dormancy in eggplant seeds. Three QTLs (dr1.1, dr2.1, and dr6.1) related to seed dormancy were detected on three chromosomes of eggplant using the QTL-Seq technique. By combining nonsynonymous sites within the candidate regions and gene functional annotation analysis, nine candidate genes were selected from three QTL candidate regions. According to the germination results on the eighth day, the male parent was not dormant, but the female parent was dormant. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the expression of nine candidate genes, and the Smechr0201082 gene showed roughly the same trend as that in the phenotypic data. We proposed Smechr0201082 as the potential key gene involved in regulating the dormancy of eggplant seeds. The results of seed experiments with different concentrations of gibberellin A3 (GA3) showed that, within a certain range, the higher the gibberellin concentration, the earlier the emergence and the higher the germination rate. However, higher concentrations of GA3 may have potential effects on eggplant seedlings. We suggest the use of GA3 at a concentration of 200–250 mg·L−1 to treat dormant seeds. This study provides a foundation for the further exploration of genes related to the regulation of seed dormancy and the elucidation of the molecular mechanism of eggplant seed dormancy and germination.
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Foley, Michael E. "Effect of Soluble Sugars and Gibberellic Acid in Breaking Dormancy of Excised Wild Oat (Avena fatua) Embryos." Weed Science 40, no. 2 (1992): 208–14. http://dx.doi.org/10.1017/s0043174500057246.
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Dormant line M73 wild oat caryopses were utilized to develop a system for the culture of excised embryos, to evaluate whether embryo dormancy exists, and to investigate the physiological basis for breaking dormancy. Dormant embryos cultured on N6 medium solidified with 0.25% Bacto agar displayed 70% germination in 2 d compared with approximately 20% for the other gelling agents. The non-plant-based gelling agent gellum at a concentration of 0.25% was selected for further experiments on breaking dormancy after it was determined that concentrations ≥ 0.5% decreased the rate of germination. Amending N6 medium with concentrations of 0.1 to 10 μM gibberellic acid (GA) increased the rate and extent of germination. Embryos treated with 0 to 0.01 μM GA required 6 d to attain 90% germination. Germination of dormant embryos on N6 medium without GA suggested that either true embryo dormancy did not exist in M73 or some constituent of the N6 medium promoted breaking of dormancy. Subsequent experiments indicated that the 88 mM sucrose was the constituent in the N6 medium responsible for breaking dormancy. Concentrations of sucrose from 40 to 200 mM were effective in breaking dormancy. Ten μM GA increased the rate and extent of germination of embryos cultured with 88 to 200 mM sucrose. At 88 mM, fructose, maltose, glucose, and sucrose all broke embryo dormancy. Fructose was the most active soluble sugar for breaking embryo dormancy, promoting nearly 100% germination in 4 d. As with sucrose, there was an interaction between GA and the soluble sugars in breaking dormancy. Ten μM GA with 88 mM fructose provided nearly 100% germination in 1 d. Amylose, but not amylopectin or pullulan, may substitute for soluble sugars. However, with 10 μM GA amylose, amylopectin and pullulan were equally effective in breaking dormancy. Breaking dormancy of embryos on N6 medium was independent of temperatures from 12 to 24 C in the presence of GA, but in its absence the optimum was 12 C. Application of GA to dormant caryopses significantly increased and decreased the level of glucose and sucrose, respectively, in the embryo. Gibberellic acid had a similar effect on glucose and sucrose in the endosperm tissue, except the differences were not significant at all times after treatment. The change in carbohydrate metabolism, especially in embryo tissue, may be important when considered in context with the observation that soluble sugars and GA act independently in breaking dormancy in excised M73 embryos. Breaking wild oat embryo dormancy with GA may be mainly a substitution for sugar requirement.
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Wang, Mei, René M. van der Meulen, Karin Visser, Henk-Peter Van Schaik, Bert Van Duijn, and Albertus H. de Boer. "Effects of dormancy-breaking chemicals on ABA levels in barley grain embryos." Seed Science Research 8, no. 2 (1998): 129–37. http://dx.doi.org/10.1017/s0960258500004025.
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AbstractThe endogenous ABA contents of dormant and nondormant barley grains were determined following application of different compounds to break dormancy. The chemicals used for breaking of dormancy in intact dormant grains were weak and strong acids, alcohols, hydrogen peroxide, cyanide, nitrate, salicylic acid, gibberellic acid and fusicoccin. The dormancy-breaking compounds could be classified into two major groups: compounds that caused a decrease in endogenous ABA (class I) and compounds which did not affect endogenous ABA (class II). Class I compounds included gibberellic acid, ethanol, hydrogen peroxide, nitrate, salicylic acid; class II compounds were fusicoccin, acid (H2SO4), sodium azide, n-caproic acid. In addition, these dormancy-breaking compounds were able to stimulate the germination rate when applied to embryos isolated from dormant grains. The concentrations necessary for stimulation of germination of isolated embryos were much lower than the concentrations for breaking the dormancy of intact grains. After embryos were isolated from dormant grains and incubated in water, ABA was determined in both embryos and in the incubation media. The class I compounds stated above also reduced ABA content in the incubation medium of isolated embryos, while class II compounds had no effect on ABA content of the medium. External application of ABA could overcome the effect of dormancy-breaking compounds of class I but not of class II. The results suggest that in the presence of the agents belonging to class II, ABA responsiveness of isolated embryos from dormant grains is decreased, compared to nontreated embryos.
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Gill, GS, and WM Blacklow. "Variations in seed dormancy and rates of development of great brome, Bromus diandrus Roth., as adaptations to the climates of southern Australia and implications for weed control." Australian Journal of Agricultural Research 36, no. 2 (1985): 295. http://dx.doi.org/10.1071/ar9850295.
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Seeds of great brome, B. diandrus, were collected from 14 sites across southern Australia and sown at Perth, W.A. The duration of seed dormancy varied among the seed accessions when produced at the common field site of Perth, which suggested that variations in dormancy were genetically controlled. The environment of Perth shortened the duration of dormancy in all the accessions but did not affect their ranking, indicating a lack of genotype x environment interaction. The duration of dormancy was positively correlated (r = 0.78) with the duration of the rain-free summers of the site of collection. Dormancy was not due to hard-seededness and non-dormant seeds germinated within 40 h of wetting at 20�C. The seed dormancy was limited to about 5 months under the storage conditions examined. Dormant seed was stimulated to germinate by gibberellic acid (2.89 mM) and dormant seed of the accession from Geraldton also responded to removal of the lemma and palea or to leaching with water. The time taken for accessions to 'panicle peep' was positively correlated (r = 0.83) with the length of the rainy winters of the sites of collection. The results show great brome has adapted genetically to the climate of southern Australia. Cropping systems that exploit the lack of residual dormancy and the potential for rapid and complete germination s
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Fadón, Erica, Eduardo Fernandez, Helen Behn, and Eike Luedeling. "A Conceptual Framework for Winter Dormancy in Deciduous Trees." Agronomy 10, no. 2 (2020): 241. http://dx.doi.org/10.3390/agronomy10020241.
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The perennial life strategy of temperate trees relies on establishing a dormant stage during winter to survive unfavorable conditions. To overcome this dormant stage, trees require cool (i.e., chilling) temperatures as an environmental cue. Numerous approaches have tried to decipher the physiology of dormancy, but these efforts have usually remained relatively narrowly focused on particular regulatory or metabolic processes, recently integrated and linked by transcriptomic studies. This work aimed to synthesize existing knowledge on dormancy into a general conceptual framework to enhance dormancy comprehension. The proposed conceptual framework covers four physiological processes involved in dormancy progression: (i) transport at both whole-plant and cellular level, (ii) phytohormone dynamics, (iii) genetic and epigenetic regulation, and (iv) dynamics of nonstructural carbohydrates. We merged the regulatory levels into a seasonal framework integrating the environmental signals (i.e., temperature and photoperiod) that trigger each dormancy phase.
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Liyanage, Ganesha S., and Mark K. J. Ooi. "Do dormancy-breaking temperature thresholds change as seeds age in the soil seed bank?" Seed Science Research 27, no. 1 (2016): 1–11. http://dx.doi.org/10.1017/s0960258516000271.
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AbstractIn fire-prone ecosystems, many species regenerate after fire from persistent soil seed banks. Species with physically dormant (PY) seeds have dormancy broken by fire-related heat. The magnitude of post-fire recruitment, to predict response to varying fire severity, is commonly estimated by testing dormancy-breaking temperature thresholds of fresh PY seeds. However, seeds spend years in the soil during the inter-fire period, and determining whether dormancy-breaking thresholds change over time is essential to accurately predict population persistence. Germination of four south-eastern Australian PY species from the Fabaceae family (Acacia linifolia, Aotus ericoides, Bossiaea heterophylla and Viminaria juncea) were studied. Dormancy-breaking temperature thresholds vary inter-specifically and the species represented either high or low dormancy-breaking threshold classes. Freshly collected seeds, and seeds that had been buried in the field or stored in dry laboratory conditions for 6 and 18 months were subjected to a fire-related range of heat treatments (40–100°C). Seed ageing increased germination response to heat treatments, effectively lowering the dormancy-breaking thresholds of three species. The fourth species, A. linifolia, initially had a relatively large non-dormant fraction which was lost as seeds aged, with older seeds then displaying PY broadly similar to the other study species. Patterns of threshold decay were species-specific, with the thresholds and viability of low-threshold species declining more rapidly than high-threshold species. The non-dormant fraction did not increase over time for any of our study species. Instead of increasing their non-dormant fraction, as is common in other vegetation types, these fire-prone PY species displayed a change of dormancy-breaking temperature thresholds. This is an important distinction, as maintaining dormancy during the inter-fire period is essential for population persistence. While changes in sensitivity to dormancy-breaking treatments have previously been reported as seeds age, our study provides the first test of changes to temperature thresholds, which increases the range of germination response from the seed bank under varying fire severity.
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Amissah, Haneef Ahmed, Stephanie E. Combs, and Maxim Shevtsov. "Tumor Dormancy and Reactivation: The Role of Heat Shock Proteins." Cells 13, no. 13 (2024): 1087. http://dx.doi.org/10.3390/cells13131087.
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Tumors are a heterogeneous group of cell masses originating in various organs or tissues. The cellular composition of the tumor cell mass interacts in an intricate manner, influenced by humoral, genetic, molecular, and tumor microenvironment cues that dictate tumor growth or suppression. As a result, tumors undergo a period of a dormant state before their clinically discernible stage, which surpasses the clinical dormancy threshold. Moreover, as a genetically imprinted strategy, early-seeder cells, a distinct population of tumor cells, break off to dock nearby or extravasate into blood vessels to secondary tissues, where they form disseminated solitary dormant tumor cells with reversible capacity. Among the various mechanisms underlying the dormant tumor mass and dormant tumor cell formation, heat shock proteins (HSPs) might play one of the most important roles in how the dormancy program plays out. It is known that numerous aberrant cellular processes, such as malignant transformation, cancer cell stemness, tumor invasion, metastasis, angiogenesis, and signaling pathway maintenance, are influenced by the HSPs. An accumulating body of knowledge suggests that HSPs may be involved in the angiogenic switch, immune editing, and extracellular matrix (ECM) remodeling cascades, crucial genetically imprinted strategies important to the tumor dormancy initiation and dormancy maintenance program. In this review, we highlight the biological events that orchestrate the dormancy state and the body of work that has been conducted on the dynamics of HSPs in a tumor mass, as well as tumor cell dormancy and reactivation. Additionally, we propose a conceptual framework that could possibly underlie dormant tumor reactivation in metastatic relapse.
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Peroni, Patricia A. "Field and Laboratory Investigations of Seed Dormancy in Red Maple (Acer Rubrum L.) from the North Carolina Piedmont." Forest Science 41, no. 2 (1995): 378–86. http://dx.doi.org/10.1093/forestscience/41.2.378.
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Abstract Field and laboratory investigations were conducted using seeds collected from red maple populations located in the North Carolina piedmont to determine: (1) the percentage of red maple seedling establishment each spring that can be attributed to dormant seeds, (2) the percentage of seeds that display dormancy upon dispersal, (3) the effect of short periods of dry conditions at 20-22°C on dormancy and seed viability. The greenhouse results indicated that red maple from these populations display moderate levels of seed dormancy (14%) when provided with conditions conducive to germination immediately upon dispersal. However, in the field, the majority of red maple seedlings that established in both 1988 (59%) and 1989 (nearly 100%) emerged from dormant seeds. The dry delay treatment led to significant increases in seed dormancy and decreases in seed viability, which suggest that some seed dormancy in red maple may be acquired rather than innate. Maternal families showed significant variation in levels of seed dormancy, and the effects of the dry delay treatment on seed viability also varied among maternal families. For. Sci. 41(2):378-386.
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Alvarado, Veria, and Kent J. Bradford. "Hydrothermal time analysis of seed dormancy in true (botanical) potato seeds." Seed Science Research 15, no. 2 (2005): 77–88. http://dx.doi.org/10.1079/ssr2005198.
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As seed dormancy is released within a seed population, both the rate and percentage of germination increase progressively with increasing dose of a dormancy-breaking treatment or condition. Population-based models can account for this behaviour on the basis of shifting response thresholds as dormancy is alleviated. In particular, hydrothermal time analysis of germination sensitivity to water potential (Ψ) and temperature (T) can describe these features of seed behaviour. We used the hydrothermal time model to analyse the effects of dormancy-breaking treatments on germination of dormant true (botanical) potato (Solanum tuberosumL.) seeds (TPS). After-ripening (37°C and 4% seed moisture content) of TPS for 7 or 30 days partially or fully alleviated primary dormancy. The median base water potential required to prevent germination [Ψb(50)] decreased from –0.25 MPa in control seeds to –0.87 MPa and –1.83 MPa after 7 and 30 days of after-ripening, respectively. In contrast, the base temperature for germination (Tb) was relatively unaffected (0–3.3°C). Fluridone (50 μM), an inhibitor of abscisic acid (ABA) biosynthesis, also promoted germination of dormant TPS and lowered Ψb(50), indicating a role forde novosynthesis of ABA during dormancy maintenance. Moist chilling (3 days at 4°C) or gibberellin (100 μM) alleviated secondary dormancy and lowered Ψb(50) values from –0.08 MPa to –0.36 and –0.87 MPa, respectively. The hydrothermal time model allows quantification of dormancy levels and explains why changes in germination speed and percentage are closely correlated during dormancy alleviation.
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Warner, R. L., D. A. Kudrna, S. C. Spaeth, and S. S. Jones. "Dormancy in white-grain mutants of Chinese Spring wheat (Triticum aestivum L.)." Seed Science Research 10, no. 1 (2000): 51–60. http://dx.doi.org/10.1017/s0960258500000064.
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AbstractRed wheats (Triticum aestivum L.) are generally more dormant and sprout resistant than white wheats. Whether this is caused by pleiotropic effectsof the red grain colour genes (R) on dormancy and coat colour, or to tight linkage between R and dormancy genes has not been fully resolved. To directly determine the effect of the R1 allele on dormancy, mutations were induced with sodium azide in a pure line selection of the red genotype (R1R1r2r2r3r3) Chinese Spring wheat. Two white mutants (CSW01, CSW02) were recovered from M3 caryopses derived from approximately 20,000 M2 plants. Both mutants were shown to be allelic to a domesticwhite genotype (r1r1r2r2r3r3). Except for seed coat colour, CSW01 and CSW02 are morphologically indistinguishable from the wild type and are presumed to be near isogenic lines of Chinese Spring. Freshly harvested grainsproduced under four different environments were evaluated for post-harvest dormancy. In all environments, intact caryopses of all three isolines exhibited high temperature dormancy typical of cereal species, although the red wild type consistently exhibited greater dormancy than the white mutant isolines. Dormancy was dissipated by afterripening in dry storage at 37°C in a similar manner for the red and white isolines. Excised embryos of the three isolines exhibited similar levels of dormancy and sensitivities to exogenous abscisic acid. These results indicate a functional R1 allele is not absolutely required for dormancy in wheat, but does enhance its expression in caryopses with dormant (sensitive) embryos
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Sautu, Adriana, Jerry M. Baskin, Carol C. Baskin, Jose Deago, and Richard Condit. "Classification and ecological relationships of seed dormancy in a seasonal moist tropical forest, Panama, Central America." Seed Science Research 17, no. 2 (2007): 127–40. http://dx.doi.org/10.1017/s0960258507708127.
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AbstractThis is the first study to determine the class of seed dormancy (or non-dormancy) of a large number of native tree species in a tropical forest, the seasonal moist tropical forest of the Panama Canal Watershed (PCW), or to test the relationships between class of dormancy (or non-dormancy) and various seed and ecological characteristics of the constituent species. Fresh seeds of 49 of 94 tree species were non-dormant (ND), and 45 were dormant (D). Seeds of 23 species had physiological dormancy (PD), 13 physical dormancy (PY), two morphological dormancy (MD), 7 morphophysiological dormancy (MPD) and none combinational dormancy (PY+PD). Seeds with PY were significantly smaller ( < 0.1 g) and drier (moisture content < 16%) at maturity than those that were ND or in the other D classes. Seeds of 62, 42 and 53% of species dispersed in the early rainy, late rainy (LRS) and dry seasons, respectively, were ND. The majority (61%) of species with PD seeds, but only 17% of those with PY seeds, were dispersed in the LRS. The proportion of species with ND seeds was higher in large-size (63%) than in mid-size (35%) and understorey (17%) trees, but differed only slightly between non-pioneers (58%) and pioneers (54%). The proportion of species with D seeds increased only slightly through a precipitation gradient of about 3100 to 1900 mm in the PCW; however, PY increased from 19 to 32% and PD decreased from 63 to 44%.
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Goddard, Erica, Shivani Srivastava, Stanley Riddell, and Cyrus Ghajar. "113 Development of T cell-based immunotherapies to target dormant disseminated breast cancer cells." Journal for ImmunoTherapy of Cancer 8, Suppl 3 (2020): A125. http://dx.doi.org/10.1136/jitc-2020-sitc2020.0113.
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BackgroundA significant fraction of breast cancer survivors develop metastases years or even decades after initial diagnosis.1–3 Mounting evidence suggests these late recurrences arise from dormant disseminated tumor cells (DTCs).4–6 However, no therapy currently exists for targeting DTCs for the purpose of metastasis prevention. Immunotherapy represents a promising avenue to target dormant DTCs. Yet, a functional relationship between adaptive immunity and dormant DTCs has not been established.MethodsHere, we have utilized a bone marrow organotypic microvascular niche co-culture model and immunocompetent murine models of breast cancer dormancy to study the relationship between the adaptive immune response and dormant DTCs and to develop immunotherapies for the purpose of eliminating dormant DTCs and preventing breast cancer metastasis.ResultsOur data suggest that breast cancer cells downregulate MHC class I antigen presentation upon dormancy induction, identifying one mechanism of immune evasion. Strikingly, outgrowing metastases re-express MHC I and presumably upregulate antigen presentation. These data suggest that MHC-dependent T cell-based immunotherapies may not effectively kill dormant DTCs, but that MHC-independent chimeric antigen receptor (CAR) T cells may be more applicable. Using the organotypic bone marrow microvascular niche co-culture system, we have shown that CAR T cells kill both proliferating and dormant tumor cells independent of tumor cell localization in the niche and independent of tumor cell cycle status. Further, we have established preclinical immunocompetent murine models of breast cancer dormancy to compare efficacy of engineered T cell receptor (TCR) and CAR T cells in eliminating dormant DTCs. From these models of breast cancer dormancy, we have found that CAR T cells eliminate both overt metastases and DTCs in the lung and bone marrow of mice. In contrast, preliminary data suggest that TCR T cells clear overt metastases but are less effective in clearing dormant disease, lending support that MHC I downregulation during dormancy may impact the efficacy of various T cell-based immunotherapies.ConclusionsOur findings identify CAR T cells as one potential immunotherapy to eradicate dormant disease, while simultaneously identifying both CAR and TCR T cells as effective treatments for the clearance of overt metastases. In sum, our findings lay the groundwork for developing adoptive cell therapies to eliminate dormant disease and prevent death from breast cancer metastasis.ReferencesPan H, Gray R, et al. 20-Year Risks of Breast-Cancer Recurrence after Stopping Endocrine Therapy at 5 Years. N Engl J Med 2017;377, 1836–1846.Karrison T, Ferguson D, Meier P. Dormancy of mammary carcinoma after mastectomy. J Natl Cancer Inst. 1999;91, 80–85.Goss PE, & Chambers AF. Does tumour dormancy offer a therapeutic target?Nat Rev Cancer 2010;10, 871–877.Aguirre-Ghiso JA. Models, mechanisms and clinical evidence for cancer dormancy. Nat Rev Cancer 2007;7, 834–846.Klein CA. Framework models of tumor dormancy from patient-derived observations. Curr Opin Genet Dev 2011;21, 42–49.Demicheli R, Abbattista A, Miceli R, Valagussa P, & Bonadonna G. Time distribution of the recurrence risk for breast cancer patients undergoing mastectomy: further support about the concept of tumor dormancy. Breast Cancer Res Treat 1996;41, 177–185.
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Roelofs, Charlotte, Kellie A. Mouchemore, Anannya Chakrabarti, Richard P. Redvers, and Robin L. Anderson. "Abstract A010: MYC as a master regulator of dormancy in triple negative breast cancer." Cancer Research 83, no. 2_Supplement_2 (2023): A010. http://dx.doi.org/10.1158/1538-7445.metastasis22-a010.
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Abstract Dormancy is a major clinical problem in breast cancer. Although the five-year survival rate is high, 15% of the patients will relapse. Cancer cells that disseminate from the tumor (DTCs) can enter a dormant state that allows survival in the face of standard-of-care therapies. These DTCs are the source of cancer recurrence. Currently little is known about the molecular drivers that initiate dormancy. MYC is a well-known oncogene that is aberrantly regulated in many cancers, including breast cancer. It is involved in proliferation, tumorigenesis, and diapause. We propose that MYC is also a master regulator of dormancy. To investigate its role in dormancy, we generated cell lines with regulatable levels of MYC expression. Using an in vitro dormancy assay, we have shown that reduced MYC levels induce dormancy in otherwise aggressive cell lines. In mice bearing human breast tumors, the loss of MYC activity following primary tumor removal greatly reduces the extent of metastasis. The DTCs in lungs, livers, spine, and femurs are maintained as small clusters with few cells, while control mice have many and large metastases. MYC reduction maintains the DTCs in this dormant-like state for at least 32 days after primary tumor removal. Importantly, when MYC levels are restored, the DTCs exit the dormant state, and overt metastasis ensues. Currently, we are comparing the transcriptomes of dormant DTCs to actively growing metastatic cells to generate a MYC-driven dormancy signature that will elucidate potential dormancy genes to target therapeutically in the clinic. To complement our genetic studies, we are investigating pharmacological suppression of MYC activity. The bromodomain inhibitor I-BET151 reduces MYC protein levels and induces dormancy in our in vitro assay. Mice treated with I-BET151 after primary tumor removal had significantly reduced levels of metastasis in lung, liver, and spine when compared to their non-treated counterparts. Testing of this compound in an immune-competent preclinical model is currently underway. Our data imply that MYC is an important regulator of dormancy in breast cancer. Our future experiments will elucidate dormancy genes as potential targets that could lead to life-saving therapies in the clinic. Citation Format: Charlotte Roelofs, Kellie A. Mouchemore, Anannya Chakrabarti, Richard P. Redvers, Robin L. Anderson. MYC as a master regulator of dormancy in triple negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A010.
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Aqbi, Hussein, Cara Coleman, Michael Idowu, and Masoud Manjili. "Low-dose neoadjuvant chemotherapy dominates Ki67− quiescent tumor dormancy for an effective immunotherapy of breast cancer." Journal of Immunology 202, no. 1_Supplement (2019): 194.7. http://dx.doi.org/10.4049/jimmunol.202.supp.194.7.
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Abstract Breast cancer mortality is mainly due to distant recurrence of the disease. The disease recurrence is usually because of the establishment of tumor dormancy following successful treatment of early stage breast cancer. In current clinical practice, dormant tumor cells are not actively treated, because they do not respond to chemotherapy or radiation therapies. Immunotherapeutic targeting of tumor dormancy is also challenging because of the induction of tumor immunoediting, leading to tumor escape and relapse. Recently, we have characterized Ki67− quiescent and Ki67low indolent types of tumor dormancy. We demonstrated that quiescent, but not indolent, dormant tumor cells fail to undergo immunoediting and remain highly susceptible to immunotherapy. Here, we sought to develop neoadjuvant therapies for dominating a quiescent type of tumor dormancy as the best target for immunotherapy. We showed that a low dose 5-FU+Adriamycin+Cyclophosphamide (FAC) dominated Ki67− quiescent type of tumor dormancy in the neu-overexpression mouse mammary carcinoma (MMC) tumor cells. These dormant cells were effectively controlled by immunotherapy in FVBN202 transgenic mouse model of spontaneous breast cancer. Since the antibiotic azithromycin has been shown to effectively eliminate senescent cells, we also sought to determine its efficacy against dormant tumor cells. We demonstrated that azithromycin specifically induced apoptosis in FAC-induced dormant tumor cells. All together, the results suggest that use of less toxic, low dose chemotherapy combined with azithromycin in a neoadjuvant setting could lead to the elimination of dormant tumor cells by immunotherapy.
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Fidler, Justyna, Edyta Zdunek-Zastocka, and Wiesław Bielawski. "Regulation of abscisic acid metabolism in relation to the dormancy and germination of cereal grains." Acta Societatis Botanicorum Poloniae 84, no. 1 (2015): 3–11. http://dx.doi.org/10.5586/asbp.2015.004.
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Seed dormancy is of particular importance in the cultivation of cereals, as it directly affects the quality of crop yield. If the dormancy period is too short, this may lead to pre-harvest sprouting, whereas a dormancy period that is too long may cause uneven germination; both of these scenarios are associated with economic losses. Most enzymes engaged in the metabolism of abscisic acid (ABA) have been identified, and significant progress has been made in understanding the role of this phytohormone in the induction and maintenance of dormancy, mainly as a result of research conducted in <em>Arabidopsis</em>. Much less is known about the metabolism and function of ABA in cereal grains, especially in relation to dormancy and germination. This review focuses on the regulation of ABA metabolism in dormant and non-dormant cereal grains, in both the dry state and upon imbibition. Moreover, this review describes the influence of factors such as after-ripening, light, temperature, nitric oxide, and reactive oxygen species (ROS) on the dormancy and germination of cereal grains. These factors, with the exception of ROS, appear to affect the level of dormancy and germination of grains through regulation of ABA metabolism.
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Sakai, Keiichiro, Yohei Kondo, Kazuhiro Aoki, and Yuhei Goto. "Molecular and Biophysical Perspectives on Dormancy Breaking: Lessons from Yeast Spore." Biomolecules 15, no. 5 (2025): 701. https://doi.org/10.3390/biom15050701.
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Dormancy is a physiological state that enables cells to survive under adverse conditions by halting their proliferation while retaining the capacity to resume growth when conditions become favorable. This remarkable transition between dormant and proliferative states occurs across a wide range of species, including bacteria, fungi, plants, and tardigrades. Among these organisms, yeast cells have emerged as powerful model systems for elucidating the molecular and biophysical principles governing dormancy and dormancy breaking. In this review, we provide a comprehensive summary of current knowledge on the molecular mechanisms underlying cellular dormancy, with particular focus on the two major model yeasts: Saccharomyces cerevisiae and Schizosaccharomyces pombe. Recent advances in multifaceted approaches—such as single-cell RNA-seq, proteomic analysis, and live-cell imaging—have revealed dynamic changes in gene expression, proteome composition, and viability. Furthermore, insights into the biophysical properties of the cytoplasm have offered new understanding of dormant cell regulation through changes in cytoplasmic fluidity. These properties contribute to both the remarkable stability of dormant cells and their capacity to exit dormancy upon environmental cues, deepening our understanding of fundamental cellular survival strategies across diverse species.
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Tremblay, Raymond L., Maria-Eglée Perez, Matthew Larcombe, et al. "Dormancy in Caladenia: a Bayesian approach to evaluating latency." Australian Journal of Botany 57, no. 4 (2009): 340. http://dx.doi.org/10.1071/bt08163.
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Dormancy is common in many terrestrial orchids in southern Australia and other temperate environments. The difficulty for conservation and management when considering dormancy is ascertaining whether non-emergent plants are dormant or dead. Here we use a multi-state capture–recapture method, undertaken over several seasons, to determine the likelihood of a plant becoming dormant or dying following its annual emergent period and evaluate the frequency of the length of dormancy. We assess the transition probabilities from time series of varying lengths for the following nine terrestrial orchids in the genus Caladenia: C. amoena, C. argocalla, C. clavigera, C. elegans, C. graniticola, C. macroclavia, C. oenochila, C. rosella and C. valida from Victoria, South Australia and Western Australia. We used a Bayesian approach for estimating survivorship, dormancy and the likelihood of death from capture–recapture data. Considering all species together, the probability of surviving from one year to the next was ~86%, whereas the likelihood of observing an individual above ground in two consecutive years was ~74%. All species showed dormancy of predominantly 1 year, whereas dormancy of three or more years was extremely rare (<2%). The results have practical implications for conservation, in that (1) population sizes of Caladenia species are more easily estimated by being able to distinguish the likelihood of an unseen individual being dormant or dead, (2) population dynamics of individuals can be evaluated by using a 1–3-year dormancy period and (3) survey effort is not wasted on monitoring individuals that have not emerged for many years.
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Lang, G. A., J. D. Early, N. J. Arroyave, R. L. Darnell, G. C. Martin, and G. W. Stutte. "Dormancy: Toward a Reduced, Universal Terminology." HortScience 20, no. 5 (1985): 809–12. http://dx.doi.org/10.21273/hortsci.20.5.809.
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Abstract In observing the growth phases of a plant’s many structures, a paraphrasing of J.L. Harper (7), and later Sussman and Douthit (13), comes to mind: “Some structures are born dormant, some achieve dormancy, and some have dormancy thrust upon them”. Indeed, the dormancy phenomena can be associated with essentially all meristematic regions of the plant. Accordingly, a wealth of terminology has arisen to describe various plant dormancy phenomena. While recently discussing seasonal growth processes, our use and misuse of current and historic dormancy terms led us to conclude that a simplified, descriptive dormancy terminology would be of benefit to the plant science community. Our purpose here is to review briefly the terminology now in use, critically examine dormancy phenomena and reduce terminology to a minimal number of descriptive terms, and consequently to stimulate discussion of this terminology scheme by our peers.
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Visser, Marjolein, and Amaury Beaugendre. "Conditional dormancy of Stipa lagascae (Poaceae) bulk-harvested on seed increase plots in South Tunisia: a reassessment and a surprise." Plant Ecology and Evolution 152, no. 3 (2019): 450–59. http://dx.doi.org/10.5091/plecevo.2019.1575.
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Background and aims – With the perspective to reseed degraded drylands, grass seeds are often stocked for several years. This common practice overlooks conditional dormancy and the necessity to preserve it. This paper reports on the germination ecology of Stipa lagascae Roem. & Schult., which is a circum-Mediterranean winter-growing bunch grass of high grazing value. However, the published record on its germination ecology is scarce and inconsistent.Methods – This record was reassessed through a series of germination trials in combination with dormancy breaking treatments on seeds that were mainly harvested on a seed increase plot in South-Tunisia.Key results –The surprise finding was that Stipa lagascae exhibits a particular kind of conditional dormancy for many months after harvest. Whereas dormant seeds barely germinate at 10°C in classical Petri dishes or on germination tables, they germinate massively (but not fully) when allowed full contact with a water-saturated substrate at 7–10°C in boxes. Dehulling provokes fast germination of near 100% of the seeds, thus showing that the substrate effect at low temperatures breaks most but not all dormancy in a particular seed lot. This remaining or residual dormancy is not conditional, as it can only be broken through dehulling. There are thus two distinct germination windows: a very broad one for non-dormant seed and a narrow one for conditionally dormant seed.Conclusions – A pattern is suggested whereby each seed lot evolves through a continuum from full over conditional to non-dormancy and finally mortality. However, only the state of conditional dormancy times germination optimally with regard to the start of the winter growing season in South-Tunisia. Its ecological significance should be interpreted in combination with its trypanocarpy. Reseeding for restoration purposes and to render grazing value to depleted drylands should thus use conditionally dormant seed.
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FRÉGEAU, JUDITH A., and VERNON D. BURROWS. "SECONDARY DORMANCY IN DORMOATS FOLLOWING TEMPERATURE TREATMENTS: FIELD AND LABORATORY RESPONSES." Canadian Journal of Plant Science 69, no. 1 (1989): 93–99. http://dx.doi.org/10.4141/cjps89-011.
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Partially after-ripened seeds of three dormoat lines (Avena sativa L. × A. fatua L.) were treated to induce secondary dormancy before field planting in the fall. The objectives of this experiment were to evaluate the dormancy response of the treated seeds and to determine if field performance, in terms of both survival and emergence, was improved by the treatments. Treatments consisted of imbibition and incubation of seeds at two temperatures: 4 °C for 3 wk or 30 °C for 2 wk. Both treatments increased dormancy, but differences were also noted in the type of relative dormancy expressed by each seed population under laboratory conditions. Treated seeds and the appropriate untreated control seeds were sown in the field, in fiberglass mesh bags, either in early or late fall depending on the treatment. Levels of dormant seeds retrieved from the field, at the end of the fall season, varied for each dormoat line and did not reflect the induced secondary dormancy measured before field planting. The fate of these dormant seeds after exposure to winter stresses was assessed on field-retrieved material in the spring. In relation to a late sowing of untreated seeds, the treatments were effective in improving levels of viable seeds (dormant or germinating) remaining in the ground, in the spring. However, the best performance, both in survival and emergence, was obtained with an early fall planting of untreated seeds. High loss of viability was common to both treated and untreated seeds of the three dormoat lines. The major shortcoming of dormoats seems to be in the area of cold resistance of the fall dormant seeds since damage during winter played an important role in survival.Key words: Secondary dormancy, relative dormancy, dormoats, emergence
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Molizane, Debora Manzano, Pricila Greyse dos Santos Julio, Sandra Maria Carmello-Guerreiro, and Claudio José Barbedo. "Physical, physiological and anatomical changes in Erythrina speciosa Andrews seeds from different seasons related to the dormancy degree." Journal of Seed Science 40, no. 3 (2018): 331–41. http://dx.doi.org/10.1590/2317-1545v40n3199428.
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Abstract: Dormancy, a process that allows seeds to survive in adverse environments, needs to be broken for germination to start, for example, by the disruption of the impermeable layer of seeds. Mature seeds of Erythrina speciosa present seed coat impermeability, whose degree depends on the year of production. The objective of this study was to analyze the physical, physiological, anatomical, and ultrastructural seed coat modifications, according to the environmental conditions in which seeds were produced, as well as the seed sensitivity to treatments as for breaking dormancy. E. speciosa seeds were collected for six years in a row and were analyzed as for dormancy degree. Moreover, chemical scarifications by different immersion times were applied on seeds from two production years, as well as mechanical scarification, which was an efficient methodology to overcome dormancy. Different immersion times by acid scarification were necessary to break dormancy in each harvest year. It was possible to conclude that the climatic conditions under which the mother plant is submitted can influence the dormancy degree of E. speciosa seeds, but the expected anatomical changes between dormant and non-dormant seeds were not found in seeds from this species.
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Walck, Jeffrey L., Carol C. Baskin, and Jerry M. Baskin. "Seeds of Thalictrum mirabile (Ranunculaceae) require cold stratification for loss of nondeep simple morphophysiological dormancy." Canadian Journal of Botany 77, no. 12 (2000): 1769–76. http://dx.doi.org/10.1139/b99-149.
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Seeds of the eastern North American herbaceous polycarpic perennial Thalictrum mirabile Small have differentiated but underdeveloped (small) embryos that are physiologically dormant at maturity in September. Physiological dormancy was broken effectively by cold stratification at 1°C, but embryos required temperatures [Formula: see text]15:6°C for growth after physiological dormancy was broken. Gibberellic acid substituted for cold stratification. Breaking of physiological dormancy in seeds exposed to natural temperatures in a greenhouse occurred during winter, and embryo growth and germination occurred in late winter - early spring. Furthermore, seeds in the greenhouse remained viable until the second and third (spring) germination seasons. Thus, T. mirabile seeds have the capacity to form a short-lived persistent soil seed bank. Buried seeds of T. mirabile apparently go through an annual dormancy-nondormancy cycle. Seeds buried in September 1994 were nondormant when exhumed in April 1995 and April 1996 and incubated in light at 25:15°C for 2 weeks, but they were dormant in June 1995 and September 1995. Seeds of T. mirabile have nondeep simple morphophysiogical dormancy. This is the first report of nondeep simple morphophysiological dormancy being broken by cold, and not by warm, stratification.
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Steadman, Kathryn J., Amanda J. Ellery, Ross Chapman, Andrew Moore, and Neil C. Turner. "Maturation temperature and rainfall influence seed dormancy characteristics of annual ryegrass (Lolium rigidum)." Australian Journal of Agricultural Research 55, no. 10 (2004): 1047. http://dx.doi.org/10.1071/ar04083.
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The role of temperature and rainfall during seed development in modulating subsequent seed dormancy status was studied for Lolium rigidum Gaud. (annual ryegrass). Climatic parameters relating to geographic origin were compared with annual ryegrass seed dormancy characteristics for seeds collected from 12 sites across the southern Western Australian cropping region. Seed germination was tested soon after collection and periodically during subsequent after-ripening. Temperature in the year of seed development and long-term rainfall patterns showed correlations with aspects of seed dormancy, particularly the proportion of seeds remaining dormant following 5 months of after-ripening. Consequently, for one population the temperature (warm/cool) and water supply (adequate/reduced) during seed development were manipulated to investigate the role of maternal environment in the quantity and dormancy characteristics of seeds produced. Seeds from plants grown at warm temperatures were fewer in number, weighed less, and were less dormant than those from plants grown at cool temperature. Seeds that developed under both cool temperature and reduced moisture conditions lost dormancy faster than seeds from well-watered plants. Seed maturation environment, particularly temperature, can have a significant effect on annual ryegrass seed numbers and seed dormancy characteristics.
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Tábori, K., J. Dobránszki, and A. Ferenczy. "POST-EFFECTS OF LIGHT CONDITIONS ON DORMANCY OF POTATO MICROTUBERS." Acta Agronomica Hungarica 48, no. 2 (2000): 127–32. http://dx.doi.org/10.1556/aagr.48.2000.2.1.
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The dormancy of potato microtubers produced under different photoperiodic treatments and light intensities was investigated in the varieties Desiree and Gülbaba. The dormant period was defined as the period between harvest or tuber initiation and the end of dormancy. The effects of environmental factors could be detected due to the use of a hormone-free tuber-producing system. Combined treatments had a slight effect on dormancy, while different light intensities influenced it considerably. The lower the light intensity the longer the dormant period for both cultivars. The effects of light intensities depended on the photoperiodic treatments applied for tuber induction.
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Kruk, Betina C., and Roberto L. Benech-Arnold. "Evaluation of dormancy and germination responses to temperature inCarduus acanthoides and Anagallis arvensisusing a screening system, and relationship with field-observed emergence patterns." Seed Science Research 10, no. 1 (2000): 77–88. http://dx.doi.org/10.1017/s096025850000009x.
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AbstractExperiments on the facultative winter annuals Carduus acanthoides and Anagallis arvensis were performed: (i) to determine thermal conditions that induce or release dormancy, (ii) to investigate to what extent changes in dormancy level resulting from those thermal conditions explain the seasonal pattern of emergence of these species, and (iii) to estimate required thermal time and base temperature for the germination of non-dormant seeds. Carduus acanthoides required high temperatures followed by decreasing temperatures for dormancy release; however, low winter temperatures did not induce secondary dormancy as expected for a winter annual. To the contrary, low temperatures stimulated dormancy release in the long term. InA. arvensis, dormancy relief was enhanced by dry storage at 25°C, and the response to low temperature was different depending on moisture conditions. Prolonged exposure to moist-chilling increased the dormancy level of the population, while dry storage at 4°C relieved dormancy. For both species, changes in the thermal range permissive for germination as a result of dormancy modifications explained to a large extent the timing of the emergence periods observed in the field. In neither species did base temperature for germination change with the dormancy level of the population. Thermal time required forgermination ofC. acanthoidesvaried with dormancy, while forA. arvensisseeds it was constant.
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Blair, Logan, Gabriela Auge, and Kathleen Donohue. "Effect of FLOWERING LOCUS C on seed germination depends on dormancy." Functional Plant Biology 44, no. 5 (2017): 493. http://dx.doi.org/10.1071/fp16368.
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FLOWERING LOCUS C (FLC) has a major regulatory role in the timing of flowering in Arabidopsis thaliana (L.) Heynh. and has more recently been shown to influence germination. Here, we investigated the conditions under which FLC influences germination, and demonstrated that its effect depends on the level of primary and secondary dormancy and the temperature of seed imbibition. We tested the germination response of genotypes with different degrees of FLC activity over the course of after-ripening and after secondary dormancy induction by hot stratification. Genotypes with high FLC-activity showed higher germination; this response was greatest when seeds exhibited primary dormancy or were induced into secondary dormancy by hot stratification. In this study, which used less dormant seeds, the effect of FLC was more evident at 22°C, the less permissive germination temperature, than at 10°C, in contrast to prior published results that used more dormant seeds. Thus, because effects of FLC variation depend on dormancy, and because the range of temperature that permits germination also depends on dormancy, the temperature at which FLC affects germination can also vary with dormancy. Finally, we document that the effect of FLC can depend on FRIGIDA and that FRIGIDA itself appears to influence germination. Thus, pleiotropy between germination and flowering pathways in A. thaliana extends beyond FLC and involves other genes in the FLC genetic pathway.