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Davidson*, Victoria L., Dean A. Kopsell, and James E. Pollard. "The Effect of Interrupting Short Day Cycles with Day-length Extension on Floral Bud Initiation in Strawberry (Fragaria × ananasa)." HortScience 39, no. 4 (July 2004): 849C—849. http://dx.doi.org/10.21273/hortsci.39.4.849c.
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Experiments were conducted to investigate the potential effect on floral bud initiation in strawberry (Fragaria × ananasa, cv. Chandler) by interrupting inductive short day cycles with a day-length extension treatment. Vegetative plants were exposed to 10-, 15-, or 20-day cycles of inductive short days in growth chambers. After receiving an inductive short day treatment plants were transferred to a greenhouse where they were exposed to non-inductive long days, which stimulated panicle elongation. Dissections of apical meristems immediately following each cycle of short days revealed that cycles of 20 days resulted in detectable floral bud formation. After 15 days in the greenhouse, all short day treatments had initiated floral buds. In the greenhouse, under long days, subsequent flowering in cohorts of plants which had previously received inductive short days showed a positive correlation between interruption of short days with day length extension and reduction in the number of floral buds initiated on earliest emerging panicles. These results suggest potential for manipulation of floral bud induction and potentially fruit size in Chandler, and perhaps other cultivars by interruption of a cycle of inductive short days with a day length extension treatment.
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Dias, M. A., and R. M. C. S. Ratnayake. "Variation in dichogamy and myophily in two dioecious Bridelia species (Phyllanthaceae)." Australian Journal of Botany 69, no. 5 (2021): 301. http://dx.doi.org/10.1071/bt21020.
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Duodichogamy and multi-cycle dichogamy are rare forms of temporal separation of staminate and pistillate reproductive functions in angiosperms. We studied the floral phenology, breeding system and pollination of Bridelia retusa (L.) A.Juss. and Bridelia moonii Thwaites, with a particular focus on the alternation of sexual phases to determine variation in their dichogamy. Three dichogamy patterns were identified in B. retusa, including one-cycle dichogamy (staminate → pistillate or pistillate → staminate), duodichogamy (staminate → pistillate → staminate), multi-cycle dichogamy (repeated flowering cycles alternating between staminate and pistillate) and pure staminates. Except for multi-cycle dichogamy, the other dichogamy patterns were prevalent in B. moonii. This study speculated floral mimicry system in Bridelia associated with blowflies.
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Tomiozzo, Regina, Gizelli Moiano De Paula, Nereu Augusto Streck, Lilian Osmari Uhlmann, Camila Coelho Becker, Natalia Teixeira Schwab, Martina Muttoni, and Cleber Maus Alberto. "Cycle duration and quality of gladiolus floral stems in three locations of Southern Brazil." Ornamental Horticulture 24, no. 4 (October 25, 2018): 317–26. http://dx.doi.org/10.14295/oh.v24i4.1237.
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The objective of this study was to determine the cycle duration in days and the quantitative parameters, i.e. stem length, spike length and stem diameter of gladiolus floral stems as a function of the planting date and locations in the Rio Grande do Sul/Brazil. Field experiments were established between 2014-2015 in three locations (Frederico Westphalen, Itaqui and Santa Maria). The experimental design was a complete randomized block, with six gladiolus cultivars in three distinct planting dates at each location as treatments. The shift from vegetative to reproductive stage, the stem length, spike length and stem diameter were evaluated. Data was statistically analyzed by ANOVA and Tukey test. When planted during late July and early August, cultivars of early cycle(‘Purple Flora’, ‘Rose Friendship’ and ‘White Friendship’) and intermediate cycle (‘Green Star’ and ‘Jester’), produced floral stems of gladiolus in the desired patterns besides as well as having a shorter growth cycle than late cultivars (‘Gold Field’), being recommended for commercial cultivation in Southern Brazil.
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KORASIDIS, VERA A., MALCOLM W. WALLACE, and BEN JANSEN. "THE SIGNIFICANCE OF PEATLAND AGGRADATION IN MODERN AND ANCIENT ENVIRONMENTS." PALAIOS 32, no. 10 (October 19, 2017): 658–71. http://dx.doi.org/10.2110/palo.2017.030.
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Abstract: Peats are commonly used in paleoenvironmental and paleoclimatic studies but detailed sedimentological and facies models for peatlands are poorly developed relative to other sedimentary settings. A comparison of the palynology and charcoal abundances in modern and ancient Cenozoic peats (i.e., brown coals) demonstrates that, in a single cycle, their respective flora commonly evolves from inundated wetland assemblages to more elevated and well-drained forest. The repetitive nature of this pattern suggests that the changing floral compositions result from changes in substrate wetness during peatland aggradation in high rainfall settings. In this scenario, floristic changes within the peat are suggested to represent peatland facies that were controlled by the local peat-forming environment. We suggest that peatland aggradation is an important process that may ubiquitously control the floral and environmental changes documented in modern and Holocene ombrogenous peats, brown coal lithotype cycles, and perhaps black coal dulling-upwards cycles.
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Steinfort, Ursula, Mauricio A. Cisternas, Rolando García, Hermine Vogel, and Gabriela Verdugo. "Phenological cycle and floral development of Chloraea crispa (Orchidaceae)." Ciencia e investigación agraria 39, no. 2 (August 2012): 377–85. http://dx.doi.org/10.4067/s0718-16202012000200014.
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Ison, RL. "Short-Day Cycle Requirements for Floral Initiation of Stylosanthes guianensis (Aublet) Sw. var. guianensis." Functional Plant Biology 12, no. 3 (1985): 291. http://dx.doi.org/10.1071/pp9850291.
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Mature plants of the tropical legume Stylosanthes guianensis var. guianensis cv. Schofield required 20 short-day (SD) cycles (of 10-h days) for irrevocable commitment to floral initiation when returned to natural long days (LD), although the morphological changes associated with floral initiation were evident after 12-18 SD cycles. Commitment to flowering and spike production were favoured by 20 or more SD cycles. Floret number per spike and percentage seed set were not affected by return to LD. Within individual plants, sections of terminal and branch apices revealed a range of development stages. Terminal apices of well developed lateral branches were able to initiate as soon as, or sooner than, terminal apices of the main branch in this usually determinate plant; this points to individual branches having some autonomy for floral initiation, but suggests dissections made from well developed lateral branches would be a feasible method for determining floral initiation where plant replication is limited.
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Barzilay, Amalia, Hanita Zemah, Rina Kamenetsky, and Itzhak Ran. "Annual Life Cycle and Floral Development of 'Sarah Bernhardt' Peony in Israel." HortScience 37, no. 2 (April 2002): 300–303. http://dx.doi.org/10.21273/hortsci.37.2.300.
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The life cycle and morphogenesis of the floral shoot of Paeonia lactiflora Pallas cv. Sarah Bernhardt were studied under Israeli conditions. The renewal buds for the following year originate on the underground crown, at the base of the annual stems. Bud emergence begins in early spring. Stems elongate rapidly and reach heights of 50-70 cm in 60-70 days. Flowering begins in April and continues until the end of May. After flowering, the leafy stems remain green until September-October, when the leaves senesce, and the peony plant enters the “rest” stage for 3-4 months. The new monocarpic shoot initiated in the renewal bud at the end of June with the formation of the first leaf primordia and continued to increase in size until February. During summer, the renewal buds remain vegetative. The apical meristem ceases leaf formation after senescence of the aboveground shoots in the fall. During September, the apical meristem of the renewal buds reaches the generative stage and achieves the form of a dome, but remains undifferentiated. In October, floral parts become visible. Floral differentiation is terminated at the beginning of December. Floral initiation and differentiation of peony do not require low temperatures. Morphological development and florogenesis were similar to other geophyte species with an annual thermoperiodic life cycle.
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Kamenetsky, Rina, and Jacob Blaustein. "397 LIFE CYCLE AND FLORAL INITIATION OF ORNAMENTAL ALLIUM SPECIES." HortScience 29, no. 5 (May 1994): 488b—488. http://dx.doi.org/10.21273/hortsci.29.5.488b.
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The annual life cycle and development of the monocarpic shoot of some ornamental Allium species from Central Asia and the Mediterranean area have been followed from the time of meristem dome initiation in the axil of a mother plant leaf, through formation of scale, leaf and flower primordia. There are three periods of meristem activity from apex initiation to flower formation. Detailed analysis of inflorescence development has been carried out by Scanning Electronic Microscope (SEM). The life span of the Allium monocarpic shoot can be as long as 18 months. Climatic variations between Central Asian and Mediterranean areas lead to differences in the time of leaf sprout and flowering of species from the same taxonomic group. The principal mechanism of floral initiation is similar for species from both areas. Knowledge of the structure and development of the shoot will be useful for improvement of an optimal program of ornamental Allium cultivation.
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Jepson, P. C., and T. P. Healy. "The location of floral nectar sources by mosquitoes: an advanced bioassay for volatile plant odours and initial studies with Aedes aegypti (L.) (Diptera: Culicidae)." Bulletin of Entomological Research 78, no. 4 (December 1988): 641–50. http://dx.doi.org/10.1017/s0007485300015492.
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AbstractThe development and testing of a bioassay system to evaluate the potency of floral odours as mediators of long-range floral nectar source location by mosquitoes are described. The bioassay is quantitative and behaviourally discriminating, upwind flying and landing acting as indices of behavioural activity over the 24-h light:dark cycle. In initial tests, the responses of Aedes aegypti (L.) to the flowers and floral odours of ox-eye daisy (Leucanthemum vulgare) were investigated. A. aegypti exhibited a biphasic diel cycle of nectar-feeding behaviour and landed on modified flowers that retained either their disc or ray florets. Most significantly, the mosquitoes responded in a similar way to the odour of L. vulgare in the absence of visual stimuli or nutritional cues. They did not respond to solvent extracts of ox-eye daisy flowers.
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Martins, Rosária Da Costa Faria, Rogério Gomes Pêgo, Eleandro Silva da Cruz, Mateus Marques Bueno, and Daniel Fonseca de Carvalho. "Postharvest Quality of Cut Zinnia Flowers Cultivated Under Different Irrigation Levels and Growing Seasons." Journal of Agricultural Studies 9, no. 1 (January 20, 2021): 303. http://dx.doi.org/10.5296/jas.v9i1.17996.
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The quality of floral stems depends on a set of pre-harvest factors which can influence their postharvest longevity. Although the identification of visual signs of senescence through scales is decisive in assessing the loss of floral quality in the postharvest period, this scale does not exist for zinnia flowers (Zinnia elegans Jacq.). Thus, the objectives of this study were to evaluate the effect of different irrigation levels and growing seasons on the postharvest longevity of zinnia floral stems; and to determine a senescence scale to assess their durability. Therefore, zinnia plants (cv. “Red California Giant”) were cultivated in pots inside a greenhouse in Seropédica (Rio de Janeiro, Brazil), with a randomized block design, under four irrigation levels (46%, 64%, 75% and 100% of the species’ water requirement) and two cycles (autumn-winter and winter-spring). At the end of each cycle, 48 stems from each treatment were harvested and placed in containers holding 300 mL of supply water. For all irrigation levels and crop cycles, there was an increase in the fresh stem weight on the first days after harvesting and the water absorption rate was higher on the first day of evaluation. The proposed senescence scale allowed us to evaluate the loss of floral quality in the postharvest period. The stems from both cycles had satisfactory results, mainly of commercial longevity and the score 5 on the scale, which represents 100% of the stems’ market value. The main postharvest results of the zinnia floral stems were not influenced by the irrigation levels.
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Adjaloo, M. K., W. Oduro, and B. K. Banful. "Floral Phenology of Upper Amazon Cocoa Trees: Implications for Reproduction and Productivity of Cocoa." ISRN Agronomy 2012 (July 16, 2012): 1–8. http://dx.doi.org/10.5402/2012/461674.
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A study of the floral phenology of cocoa trees was carried out between 2006 and 2008 at Kubease in the Ashanti Region of Ghana, using one hundred cocoa trees from ten farm plots. The objective was to assess the contribution of floral phenology to the productivity of cocoa. Cocoa like all tropical tree species exhibited seasonally-related phenological patterns involving overlapping cycles under both intrinsic and extrinsic controls. However, unlike most tropical plants, flowering was in the rainy season. The production of new pods or cherelles increased during the major rainy season (June, July, and August), but was evenly distributed from the minor to the dry season. Production of small and medium pods peaked in August whereas production of large pods peaked in October. There was a positive correlation between new pod production and pods abortion (r = 0.69; n = 100; P < 0.05). Temperature, light intensity, and rainfall positively affected production of floral buds and production of open flowers. However, rainfall had the greatest influence on the phenological cycle of the cocoa plant. The floral phenological pattern also coincided with the activity of the main pollinators of cocoa which resulted in enhanced reproductive capacity for increased production of cocoa.
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Zhang, Xiuren, David G. Himelrick, Floyd M. Woods, and Robert C. Ebel. "Effect of Temperature, Photoperiod, and Pretreatment Growing Condition on Floral Induction in Spring-bearing Strawberry." HortScience 35, no. 4 (July 2000): 556B—556a. http://dx.doi.org/10.21273/hortsci.35.4.556b.
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`Chandler' strawberry plants (Fragaria Xananassa Duch.) were greenhouse grown under natural lighting and then placed into growth chambers at two constant temperatures of 16 and 26 °C and 2 daylengths of 9 h (SD) and 9-h photoperiod (NI) which was night interrupted with 3 hours of incandescent radiation at 30-45 μmol·s-1·m-2 PAR. Plants were given different numbers of inductive cycles in growth chambers and then moved to the greenhouse. Flowering and growth were monitored. Flowering was completely inhibited at 26 °C, regardless of pretreatment growing conditions such as pot sizes and plant ages, photoperiod, and inductive cycles. At 16 °C, SD promoted floral induction compared to NI under all inductive cycles except a 7-day induction. The minimum number of inductive cycles required at 16 °C for floral induction was dependent on photoperiod and prior greenhouse treatment. Flowering rate was also affected by greenhouse treatment, photoperiod, and inductive cycles. Runner production was affected by photoperiod and temperature × inductive cycle.
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Alanís Méndez, José Luis, Luz del Carmen Ortiz Santos, Ivette Alicia Chamorro Florescano, Juan Manuel Pech Canché, and Francisco Limón. "Pollinators and floral visitors of two orchids in a protected natural area in Tuxpan, Veracruz." Ecosistemas y Recursos Agropecuarios 6, no. 17 (May 3, 2019): 361. http://dx.doi.org/10.19136/era.a6n17.1922.
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Floral visitors, particularly pollinators, are important during the life cycle of many orchids. However, despite their biological importance, this information is still unknown in many species, particularly those in mangrove forests. The aim of this research was to study the floral visitors, as well as the pollinators, of the two orchid species Myrmecophila grandifloraand Brassavola nodosa, in a protected natural area with mangrove (RAMSAR), in Tuxpan, Veracruz, Mexico. Ants of different genera were the floral visitors of M. grandiflora, its pollinator is the carpenter bee, Xylocopa nautlana. In B. nodosa, were observed mosquitoes and ladybugs as floral visitors, the pollinator could not be registered, but it is possible that it is a species of moth (Scopula sp.). Finally, this study provides field information about floral visitors and pollinators in two orchid species in mangrove ecosystems and the evidence for pollination.
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Carter, Clay, and Robert W. Thornburg. "Is the nectar redox cycle a floral defense against microbial attack?" Trends in Plant Science 9, no. 7 (July 2004): 320–24. http://dx.doi.org/10.1016/j.tplants.2004.05.008.
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Kamenetsky, Rina, and Nazira Japarova. "Relationship between annual cycle and floral development of threeAlliumspecies from subgenusMelanocrommyum." Journal of Arid Environments 35, no. 3 (March 1997): 473–85. http://dx.doi.org/10.1006/jare.1996.0161.
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Sun, Yueyang, Yu Zou, Jing Jin, Hao Chen, Zhiying Liu, Qinru Zi, Zeyang Xiong, et al. "DIA-Based Quantitative Proteomics Reveals the Protein Regulatory Networks of Floral Thermogenesis in Nelumbo nucifera." International Journal of Molecular Sciences 22, no. 15 (July 31, 2021): 8251. http://dx.doi.org/10.3390/ijms22158251.
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The sacred lotus (Nelumbo nucifera) can maintain a stable floral chamber temperature between 30 and 35 °C when blooming despite fluctuations in ambient temperatures between about 8 and 45 °C, but the regulatory mechanism of floral thermogenesis remains unclear. Here, we obtained comprehensive protein profiles from receptacle tissue at five developmental stages using data-independent acquisition (DIA)-based quantitative proteomics technology to reveal the molecular basis of floral thermogenesis of N. nucifera. A total of 6913 proteins were identified and quantified, of which 3513 differentially abundant proteins (DAPs) were screened. Among them, 640 highly abundant proteins during the thermogenic stages were mainly involved in carbon metabolism processes such as the tricarboxylic acid (TCA) cycle. Citrate synthase was identified as the most connected protein in the protein-protein interaction (PPI) network. Next, the content of alternative oxidase (AOX) and plant uncoupling protein (pUCP) in different tissues indicated that AOX was specifically abundant in the receptacles. Subsequently, a protein module highly related to the thermogenic phenotype was identified by the weighted gene co-expression network analysis (WGCNA). In summary, the regulation mechanism of floral thermogenesis in N. nucifera involves complex regulatory networks, including TCA cycle metabolism, starch and sucrose metabolism, fatty acid degradation, and ubiquinone synthesis, etc.
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Glassop, Donna, and Anne L. Rae. "Expression of sugarcane genes associated with perception of photoperiod and floral induction reveals cycling over a 24-hour period." Functional Plant Biology 46, no. 4 (2019): 314. http://dx.doi.org/10.1071/fp18136.
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The genetic network resulting in the production of an inflorescence is complex, involving one or more pathways including the photoperiod, maturity, gibberellin and autonomous pathways, and induction and repression of genes along the pathways. Understanding the cyclic expression profile of genes involved with photoperiod perception and floral pathway induction in sugarcane, an intermediate–short day plant (ISD), is crucial for identifying key genes and understanding how the profile changes in response to floral induction signals under decreasing daylengths. Homologues of 21 genes, and some gene alleles, associated with photoperiod perception and the flower induction pathway were examined in sugarcane variety Q174 over a 24-h light-dark cycle. The strongest expression of these genes was seen in the immature spindle leaves and levels of expression generally decreased with increasing leaf age. Significant changes in gene expression levels during a 24-h cycle were observed for 16 of the 21 genes tested. We have now defined an important baseline for expression patterns over a 24-h cycle in non-inductive conditions in sugarcane. These results can be utilised to select the optimal time for detecting changes during floral induction, differences between varieties that are responsive/non-responsive to photoperiod induction, and to identify genes that may be manipulated to enhance or inhibit flowering.
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Pott, Christian, and Baoyu Jiang. "Plant remains from the Middle–Late Jurassic Daohugou site of the Yanliao Biota in Inner Mongolia, China." Acta Palaeobotanica 57, no. 2 (December 1, 2017): 185–222. http://dx.doi.org/10.1515/acpa-2017-0012.
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AbstractA late Middle–early Late Jurassic fossil plant assemblage recently excavated from two Callovian–Oxfordian sites in the vicinity of the Daohugou fossil locality in eastern Inner Mongolia, China, was analysed in detail. The Daohugou fossil assemblage is part of the Callovian–Kimmeridgian Yanliao Biota of north-eastern China. Most major plant groups thriving at that time could be recognized. These include ferns, caytonialeans, bennettites, ginkgophytes, czekanowskialeans and conifers. All fossils were identified and compared with species from adjacent coeval floras. Considering additional material from three collections housed at major palaeontological institutions in Beijing, Nanjing and Pingyi, and a recent account in a comprehensive book on the Daohugou Biota, the diversity of the assemblage is completed by algae, mosses, lycophytes, sphenophytes and putative cycads. The assemblage is dominated by tall-growing gymnosperms such as ginkgophytes, czekanowskialeans and bennettites, while seed ferns, ferns and other water- or moisture-bound groups such as algae, mosses, sphenophytes and lycophytes are represented by only very few fragmentary remains. The floral composition underlines the Callovian–Kimmeridgian age of the Yanliao Biota. The Daohugou/Yanliao flora is a typical member of the Middle to Late JurassicConiopteris-Phoenicopsisassemblage of north-eastern China, differing from the Early Cretaceous Jehol flora. Both floras probably belong to the same cycle of volcanism and sedimentation, although the Daohugou Bed is older than the Yixian Formation. The Yanliao fossil assemblage is placed in a larger palaeo-phytogeographical context and its relationships with Middle–Late Jurassic floras from north-eastern China, north-eastern and eastern Siberia and Japan are evaluated.
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Waller, Timothy J., J. Gager, Christine Constantelos, and Peter V. Oudemans. "The Role of Flowers in the Disease Cycle of Colletotrichum fioriniae and Other Cranberry Fruit Rot Fungi." Phytopathology® 110, no. 7 (July 2020): 1270–79. http://dx.doi.org/10.1094/phyto-01-20-0010-r.
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Floral extracts (FEs) can influence the infectivity and epidemiology of fruit infecting Colletotrichum species. In this study, Colletotrichum fioriniae responded to cranberry FEs with an increased rate and magnitude of secondary conidiation and appressorium formation. Four other cranberry fruit rotting species also showed an increased rate of germination in the presence of FEs. However, increased appressorium formation was observed only in the latent pathogens Coleophoma cylindrospora, Colletotrichum fructivorum, and Colletotrichum fioriniae. Two other fruit rotting species, Phyllosticta vaccinii and Allantophomopsis lycopodina, did not form appressoria while secondary conidiation was only seen with the Colletotrichum spp. When conidia of Colletotrichum fioriniae were inoculated in the presence of FE, the incidence of disease was greater on cranberry fruit. Conidia of this species also formed appressoria at lower than expected temperatures in the presence of FE. Dissection of the flowers revealed that the corolla (with stamens and stigma) was the most stimulatory part of the inflorescence. These observations suggest an important and ephemeral role of flowers in the epidemiology of fruit rot. Stimulatory floral signals were readily detected using a conidial germination bioassay and rainwater samples collected from the plant canopy throughout the growing season confirmed that bioactivity was highest during the bloom period, and declined as the fruit developed. The data presented show that floral signals can alter the growth patterns of a larger than previously observed range of fungi and the mobility of floral signals within the canopy implicates these phenology-specific cues in modifying the disease cycles of numerous plant pathogens.
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Gibernau, Marc, and Denis Barabé. "Pollination ecology of Philodendron squamiferum (Araceae)." Canadian Journal of Botany 80, no. 3 (March 1, 2002): 316–20. http://dx.doi.org/10.1139/b02-006.
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In French Guiana, inflorescences of Philodendron squamiferum Poepp. (Araceae) were regularly visited by the scarab beetle Cyclocephala simulatrix Hölne and (Scarabaeidae, Coleoptera) occasionally by Cyclocephala tylifera Hölne. The flowering cycle lasted 2 days, and the protogynous inflorescence exhibited features typical of beetle pollination (floral chamber, food rewards, flower heating). The spadix temperature was measured during the entire flowering cycle in French Guiana and at the Montreal Botanical Garden. Both sets of measurements gave a similar temperature pattern. The spadix warmed up twice at the beginning of each evening with no notable heat production between the two peaks. These two temperature peaks were well synchronized with the arrival and departure of beetles.Key words: beetle pollination, Cyclocephala, Dynastidae, floral traits, thermogenesis, French Guiana.
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Sharman, KV, M. Sedgley, and D. Aspinall. "Disruption by Temperature of Floral Evocation and Cell-Cycling in the Shoot Apical Meristem of Helipterum roseum." Functional Plant Biology 17, no. 6 (1990): 629. http://dx.doi.org/10.1071/pp9900629.
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Flowering is inhibited in plants of Helipterum roseum grown under constant 25°C temperature conditions with a 12 h photoperiod and irradiance of 250 W m-2, but not at a constant temperature of 20°C. Floral inhibition was investigated by transferring plants between the two temperature con- ditions at different times to determine the morphological stage of inhibition, and by investigating cell-cycling at the shoot apex at the two temperatures. Floral initiation in Helipterum roseum was inhibited if the temperature increase from 20 to 25°C occurred at the doming of the apical meristem, and was delayed when the increase occurred at the initiation of involucral bracts. Steady-state cell-cycling was observed in the shoot meristem at 20°C and the cell-cycle duration was estimated at the morphological stages of large vegetative meristem, doming of the meristem and initiation of the involucral bracts. The length of the cell-cycle at these stages was 64 h, 41 h and 47 h respectively. Steady-state cell-cycling was not observed in shoot apical meristems at 25°C, and the meristem did not undergo the floral transition. It is concluded that the stage of commitment to flower is the initiation of involucral bracts, and that floral initiation is inhibited at 25°C by the loss of steady-state cell-cycling at the shoot apex.
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Guo, Yi Ming, Sheng Chen, Matthew N. Nelson, Wallace Cowling, and Neil C. Turner. "Delayed water loss and temperature rise in floral buds compared with leaves of Brassica rapa subjected to a transient water stress during reproductive development." Functional Plant Biology 40, no. 7 (2013): 690. http://dx.doi.org/10.1071/fp12335.
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Leaf canopy temperature has been proposed as a rapid selection tool for drought tolerance among crop genotypes. However, floral bud temperature may be a better indicator of drought tolerance than leaf temperature in grain crops. In this study, we examined whether the floral bud and leaves of Brassica rapa L. had similar stomatal characteristics and showed similar water loss during a drying cycle. We also compared the leaf and bud temperatures when the plants were exposed to a 10-day transient water stress during reproductive development that affected flower development, increased flower abortion, increased pod abortion and reduced yield by an average of 85%. The water loss of detached leaves and floral buds showed that the stomata on the leaves closed before those of the floral buds as the leaf water potential decreased. Consistent with the water loss studies, the temperature of the intact bud showed a delayed increase during the drying process compared with the leaves. This suggested that floral bud temperature could be a useful indicator of the water status of the reproductive organs of B. rapa.
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Azad, Rumana, K. L. Wasantha Kumara, Gamini Senanayake, R. A. A. K. Ranawaka, D. K. N. G. Pushpakumara, and Sudarshanee Geekiyanage. "Flower morphological diversity of cinnamon (Cinnamomum verum Presl) in Matara District, Sri Lanka." Open Agriculture 3, no. 1 (July 1, 2018): 236–44. http://dx.doi.org/10.1515/opag-2018-0025.
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Abstract The cinnamon flowers exhibit protogynous dichogamy with 2 flower types “Type A” and “Type B” which first flowers during morning and evening respectively. This floral cycle causes a temporal barrier to the maintenance of elite breeding material and for hybridization with desired parents. Determination of variation in flower and inflorescence morphology can shed light on functional diversity in “Type A” and “Type B” flowers. In order to study these variations, a survey of cultivated cinnamon lands and wild habitats was conducted in fifteen locations in the Matara district. Peduncle length (PDL), flower length (FL), flower width (FW), and floral tube length (FTL) varied among cinnamon accessions collected. The variation in tepal shape was distinct: the two whorls of tepals of a single flower exhibited two shapes. The current investigation of differences in inflorescence, floral morphology and floral abnormalities of Cinnamomum verum provides information about their diversity, and recommends molecular analysis to further determine the genetic basis of two flower types in progynous dichogamy.
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Ramya, Mummadireddy, Seonghoe Jang, Hye-Ryun An, Su-Young Lee, Pil-Man Park, and Pue Hee Park. "Volatile Organic Compounds from Orchids: From Synthesis and Function to Gene Regulation." International Journal of Molecular Sciences 21, no. 3 (February 10, 2020): 1160. http://dx.doi.org/10.3390/ijms21031160.
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Orchids are one of the most significant plants that have ecologically adapted to every habitat on earth. Orchids show a high level of variation in their floral morphologies, which makes them popular as ornamental plants in the global market. Floral scent and color are key traits for many floricultural crops. Volatile organic compounds (VOCs) play vital roles in pollinator attraction, defense, and interaction with the environment. Recent progress in omics technology has led to the isolation of genes encoding candidate enzymes responsible for the biosynthesis and regulatory circuits of plant VOCs. Uncovering the biosynthetic pathways and regulatory mechanisms underlying the production of floral scents is necessary not only for a better understanding of the function of relevant genes but also for the generation of new cultivars with desirable traits through molecular breeding approaches. However, little is known about the pathways responsible for floral scents in orchids because of their long life cycle as well as the complex and large genome; only partial terpenoid pathways have been reported in orchids. Here, we review the biosynthesis and regulation of floral volatile compounds in orchids. In particular, we focused on the genes responsible for volatile compounds in various tissues and developmental stages in Cymbidium orchids. We also described the emission of orchid floral volatiles and their function in pollination ecology. Taken together, this review will provide a broad scope for the study of orchid floral scents.
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Voss, Higor Modesto Garlet, Otávio dos Santos Escobar, Vinicius Severo Trivisiol, Mariane Peripolli, Maicon Pivetta, Jaíne Rubert, Elisandro Azeredo Nunes, and Sylvio Henrique Bidel Dornelles. "Phenology and thermal requirements of the species Cyperus difformis L. in southern Brazil." Acta Scientiarum. Biological Sciences 43 (March 23, 2021): e47560. http://dx.doi.org/10.4025/actascibiolsci.v43i1.47560.
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Cyperus difformis L. is a Cyperaceae, annual, of natural occurrence in marshy environments in southern Brazil, considered a weed in irrigated rice crops. Studies on its development are scarce, especially regarding its cycle and thermal requirements. Therefore, the objective of this work was to determine the base temperature, the thermal sum and the duration of the different sub-periods of the biological cycle of the species. The experiment was carried out at the Campus of the Universidade Federal de Santa Maria – UFSM, Santa Maria, Rio Grande do Sul, in four sowing seasons. In a completely delineated design and factorial scheme involving five soil water conditions (water depth and 50% soil water retention capacity [WRC]) from the sowing, water depth and 50% WRC introduced 21 days after emergence and 100% WRC during the whole cycle, with six repetitions each. Each experimental unit consisted of a cultivated in pot plant with 11 L capacity filled with soil. The cycle of the plants was subdivided into the sowing-emergence sub-periods, emergence-emission of the floral tassel and emission of the floral-maturing physiological tassel, being estimated the thermal requirements for the species. The conditions of the soil water condition the base temperature, the sum of the degree-days and the duration of the species cycle. The base temperature varies for each treatment, the sum of degrees-day decreases with the water deficit and the plants under flood accelerate the biological cycle.
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Piunno, Kevin F., Gregory Golenia, Ekaterina A. Boudko, Cassandra Downey, and A. Maxwell P. Jones. "Regeneration of shoots from immature and mature inflorescences of Cannabis sativa." Canadian Journal of Plant Science 99, no. 4 (August 1, 2019): 556–59. http://dx.doi.org/10.1139/cjps-2018-0308.
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Cannabis sativa is usually clonally propagated from plants in the vegetative phase. However, phenotypic traits such as yield and chemical composition can only be assessed in unfertilized plants reaching the end of their life cycle and there are no peer-reviewed methods to propagate flowering plants. In this study, immature (three cultivars) and mature (one cultivar) floral explants were cultured on thidiazuron and shoot development was observed in both the immature and mature explants. This provides the first report of micropropagation from floral tissues in C. sativa and will enable plants to be clonally propagated up to the date of harvest.
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Arnold, Sarah E. J., Samantha J. Forbes, David R. Hall, Dudley I. Farman, Puran Bridgemohan, Gustavo R. Spinelli, Daniel P. Bray, et al. "Floral Odors and the Interaction between Pollinating Ceratopogonid Midges and Cacao." Journal of Chemical Ecology 45, no. 10 (October 2019): 869–78. http://dx.doi.org/10.1007/s10886-019-01118-9.
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AbstractMost plant species depend upon insect pollination services, including many cash and subsistence crops. Plants compete to attract those insects using visual cues and floral odor which pollinators associate with a reward. The cacao tree, Theobroma cacao, has a highly specialized floral morphology permitting pollination primarily by Ceratopogonid midges. However, these insects do not depend upon cacao flowers for their life cycle, and can use other sugar sources. To understand how floral cues mediate pollination in cacao we developed a method for rearing Ceratopogonidae through several complete lifecycles to provide material for bioassays. We carried out collection and analysis of cacao floral volatiles, and identified a bouquet made up exclusively of saturated and unsaturated, straight-chain hydrocarbons, which is unusual among floral odors. The most abundant components were tridecane, pentadecane, (Z)-7-pentadecene and (Z)-8-heptadecene with a heptadecadiene and heptadecatriene as minor components. We presented adult midges, Forcipomyia sp. (subgen. Forcipomyia), Culicoides paraensis and Dasyhelea borgmeieri, with natural and synthetic cacao flower odors in choice assays. Midges showed weak attraction to the complete natural floral odor in the assay, with no significant evidence of interspecific differences. This suggests that cacao floral volatiles play a role in pollinator behavior. Midges were not attracted to a synthetic blend of the above four major components of cacao flower odor, indicating that a more complete blend is required for attraction. Our findings indicate that cacao pollination is likely facilitated by the volatile blend released by flowers, and that the system involves a generalized odor response common to different species of Ceratopogonidae.
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Rabelo, Josimara Mendes, Maria do Céu Monteiro Cruz, Deilson de Almeida Alves, João Esdras Lima, Letícia Alves Carvalho Reis, and Nubia Cassiana Santos. "Reproductive phenology of yellow pitaya in a high-altitude tropical region in Brazil." Acta Scientiarum. Agronomy 42 (May 27, 2020): e43335. http://dx.doi.org/10.4025/actasciagron.v42i1.43335.
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Pitaya species cultivation in Brazil is recent, and information on the production of the species Selenicereus megalanthus, known as yellow pitaya, is non-existent because research in the country has focused on the species Hylocereus undatus. The research was carried out with the objective of evaluating the reproductive phenology of the species S. megalanthus, in a high-altitude climate conditions in Brazil. The study orchard of yellow pitaya was located at an altitude of 726 metres, 18º 04' 15" S latitude and 43º 28' 15" W longitude, and has an Aw climate, classified as high-altitude tropical. Phenological evaluations were carried out through visual observations, from the beginning of floral button formation until the end of the fruit harvest, during three production cycles. On each plant, flower buds were marked to determine the time from floral button formation until flower anthesis and from flower fertilisation until fruit ripening. The period of flowering and harvesting of the yellow pitaya was determined according to the phenological stage records. Flowering began in the spring, with successive flowering events until the autumn. The time between floral button formation until anthesis ranged from 46 to 55 days. The time from flower fertilisation until fruit ripening ranged from 96 to 110 days. Fruit harvest began in the summer and ended in winter. The reproductive cycle of S. megalanthus is longer than H. undatus and H. polyrhizus, which are also cultivated in Brazil, ranging from 147 to 166 days from floral button formation to fruit harvest.
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Kharadi, Roshni R., Jeffrey K. Schachterle, Xiaochen Yuan, Luisa F. Castiblanco, Jingyu Peng, Suzanne M. Slack, Quan Zeng, and George W. Sundin. "Genetic Dissection of the Erwinia amylovora Disease Cycle." Annual Review of Phytopathology 59, no. 1 (August 25, 2021): 191–212. http://dx.doi.org/10.1146/annurev-phyto-020620-095540.
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Fire blight, caused by the bacterial phytopathogen Erwinia amylovora, is an economically important and mechanistically complex disease that affects apple and pear production in most geographic production hubs worldwide. We compile, assess, and present a genetic outlook on the progression of an E. amylovora infection in the host. We discuss the key aspects of type III secretion–mediated infection and systemic movement, biofilm formation in xylem, and pathogen dispersal via ooze droplets, a concentrated suspension of bacteria and exopolysaccharide components. We present an overall outlook on the genetic elements contributing to E. amylovora pathogenesis, including an exploration of the impact of floral microbiomes on E. amylovora colonization, and summarize the current knowledge of host responses to an incursion and how this response stimulates further infection and systemic spread. We hope to facilitate the identification of new, unexplored areas of research in this pathosystem that can help identify evolutionarily susceptible genetic targets to ultimately aid in the design of sustainable strategies for fire blight disease mitigation.
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Greene, Duane W. "Reducing Floral Initiation and Return Bloom in Pome Fruit Trees—Applications and Implications." HortTechnology 10, no. 4 (January 2000): 740–43. http://dx.doi.org/10.21273/horttech.10.4.740.
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Regulation of biennial bearing in pome fruit is usually accomplished by chemically removing fruit during the “on” cycle. The advantages and disadvantages of regulating biennial bearing by inhibiting flowering in the “off” cycle were discussed. Gibberellins and the two phenyl urea cytokinin-like compounds, thidiazuron and CPPU have been shown to inhibit flowering in pome fruit. It was concluded that inhibition of flowering with commercially available gibberellins was not a commercially acceptable approach to regulate biennial bearing. The inhibition of flowering was erratic, fruit thinning and increased fruit set could not be predicted, and seed abortion following gibberellin application could predispose fruit to reduced postharvest life because of reduced calcium uptake. Regulation of flowering by inhibiting flower bud formation appeared to be a viable way to regulate cropping on nonbearing tress or trees that were not carrying a crop.
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Scagel*, Carolyn. "Mycorrhiza-induced Changes in Partitioning and Composition Alters Flower and Vegetative Production of Floral Geophytes." HortScience 39, no. 4 (July 2004): 767C—767. http://dx.doi.org/10.21273/hortsci.39.4.767c.
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Resource partitioning and plant storage components are important factors that influence the productivity and profitability of geophyte species produced as floral crops. We determined that inoculation with arbuscular mycorrhizal fungi (AMF) can alter different plant characteristics affecting productivity and quality of bulb and cut flower production of several floral geophytes including Brodiaea laxa, Zephyranthes sp., Sparaxis tricolor, Freesia × hybrida, Zantedeschia sp., and Canna sp. Plant growth, flower production, bulb/corm/tuber (bulb) production and composition were measured for two growth cycles after inoculation with Glomus intraradices. In general, shoots and flowers on plants inoculated with AMF emerged earlier than shoots and flowers on non-inoculated plants for species that produced most of their leaf area prior to flower emergence. However for species that produced leaves throughout the growth cycle or large flowers early in the growth cycle, AMF inoculation delayed shoot emergence and flower emergence. Many species that exhibited an earlier flower emergence or produced more flowers in response to AMF inoculation also produced smaller daughter bulbs and more offsets than non-inoculated plants. Across all species, the concentrations and contents of several storage components (Zn, S, and N, amino acids, and carbohydrates) that influence bulb quality were increased by AMF inoculation. Changes in partitioning between bulb and flower production resulting from AMF inoculation altered important aspects of commercial geophyte production for flowers or bulbs. AMF-induced increases in mineral uptake and resource storage are also related to aspects of quality important in the production of vegetative propagates.
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Yao, Jiping. "Global Jurassic floras and climate." Paleontological Society Special Publications 6 (1992): 320. http://dx.doi.org/10.1017/s2475262200008807.
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The present day vegetation types on the earth are to a large extent controlled by climatic conditions that are mainly reflected in variations in moisture availability and temperature through the annual cycle. Therefore, fossil plants can be used as a tool to elucidate both spatial and temporal climatic changes. The global climates of the Jurassic can be interpreted with fossil floras because many parts of world have yielded abundant floral localities. Those records not only provide a strong basis for the qualitative depiction of vegetation patterns, but also provide quantitative data for the reconstruction of paleophytogeographic provinces and climatic changes. The computer program known as “Detrended Correspondence Analysis” written by Hill (1979) was used in this study. The floral data for this quantitative approach was assembled at the generic level mainly from the published literature. By definition, it is a method based on ordination scores, that is, the species ordination scores are averages of the sample ordination scores, and vice versa.The scatter diagrams of the first two axes of genera and sample sites derived by detrended correspondence analysis were obtained for the intervals of Early, Middle, and Late Jurassic. The gradient variations of both genera and sample sites are reflected by the scores along axis 1 and 2 because axis 1 and axis 2 maximize the correlation of species and sample sites according to this technique. In the ordination score diagrams, the genera in similar climatic environments and the sample sites in similar paleogeographic regions are relatively close to each other along axis1 and axis2.One of characteristics of the Jurassic vegetation is the taxonomic stability through the period compared with other periods of time. Therefore, the generic scores of axis1 for the Early and Middle, Middle and Late, and Early and Late Jurassic can be plotted against each other. The regression line can be used to assign the scores to the ordered genera. This is the technique used to complement the ordered genera from the gradient score diagrams and to eliminate the effect of some local genera. The genera adjacent to the regression line can be reliably used to reflect climatic gradients. The gradient changes were used to define biomes and to determine phytogeographic patterns on a global scale.The quantitative analysis clearly shows that the use of floral data can achieve fast and satisfactory results in paleoclimatic studies of the Jurassic. For example, the cool-wet temperate climate is reflected by a ginkgophyte dominated deciduous flora, such as Ginkgo, Czekanowskia, Phoenicopsis, and Baiera, whereas the subtropical warm and drier climate is represented by cycad dominated floras, such as Anomozamites, Nilssonia, Pterophylum, Ptilophyllwn, Ctenis, and Otozamites. The general conclusion of earlier workers that Jurassic floras were especially uniform through the earth is true in the relative sense only, and the ordination study allows for the subdivision of the rather shallow gradients that do exist.
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Chouteau, Mathieu, Denis Barabé, and Marc Gibernau. "Thermogenesis in Syngonium (Araceae)." Canadian Journal of Botany 85, no. 2 (January 2007): 184–90. http://dx.doi.org/10.1139/b07-004.
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Floral cycles and spadix temperatures were recorded for two species of Syngonium: Syngonium schottianum Wendl. ex Schott (section Cordatum) and Syngonium angustatum Schott (section Syngonium). Both species exhibited a 3-day flowering cycle, beginning with stigma receptivity and opening of the spathe the first day, the female phase continues over the second day, and the male phase continues over the third day. These species displayed two distinct patterns of heat production during flowering. In S. schottianum, the spadix warmed up twice during the beginning of the second and third nights, but in S. angustatum, the spadix warmed up twice the second day, once the second night, and once the third day. These different thermogenic cycles are discussed in regard to other genera that are phylogenetically close or sharing similar flowering and thermogenic cycles.
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Jing, Danlong, Weiwei Chen, Ruoqian Hu, Yuchen Zhang, Yan Xia, Shuming Wang, Qiao He, Qigao Guo, and Guolu Liang. "An Integrative Analysis of Transcriptome, Proteome and Hormones Reveals Key Differentially Expressed Genes and Metabolic Pathways Involved in Flower Development in Loquat." International Journal of Molecular Sciences 21, no. 14 (July 20, 2020): 5107. http://dx.doi.org/10.3390/ijms21145107.
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Flower development is a vital developmental process in the life cycle of woody perennials, especially fruit trees. Herein, we used transcriptomic, proteomic, and hormone analyses to investigate the key candidate genes/proteins in loquat (Eriobotrya japonica) at the stages of flower bud differentiation (FBD), floral bud elongation (FBE), and floral anthesis (FA). Comparative transcriptome analysis showed that differentially expressed genes (DEGs) were mainly enriched in metabolic pathways of hormone signal transduction and starch and sucrose metabolism. Importantly, the DEGs of hormone signal transduction were significantly involved in the signaling pathways of auxin, gibberellins (GAs), cytokinin, ethylene, abscisic acid (ABA), jasmonic acid, and salicylic acid. Meanwhile, key floral integrator genes FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) and floral meristem identity genes SQUAMOSA PROMOTER BINDING LIKE (SPL), LEAFY (LFY), APETALA1 (AP1), and AP2 were significantly upregulated at the FBD stage. However, key floral organ identity genes AGAMOUS (AG), AP3, and PISTILLATA (PI) were significantly upregulated at the stages of FBE and FA. Furthermore, transcription factors (TFs) such as bHLH (basic helix-loop-helix), NAC (no apical meristem (NAM), Arabidopsis transcription activation factor (ATAF1/2) and cup-shaped cotyledon (CUC2)), MYB_related (myeloblastosis_related), ERF (ethylene response factor), and C2H2 (cysteine-2/histidine-2) were also significantly differentially expressed. Accordingly, comparative proteomic analysis of differentially accumulated proteins (DAPs) and combined enrichment of DEGs and DAPs showed that starch and sucrose metabolism was also significantly enriched. Concentrations of GA3 and zeatin were high before the FA stage, but ABA concentration remained high at the FA stage. Our results provide abundant sequence resources for clarifying the underlying mechanisms of the flower development in loquat.
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Wang, Xiaomin, Daniel K. Gingrich, Yunfei Deng, and Zonglie Hong. "A nucleostemin-like GTPase required for normal apical and floral meristem development in Arabidopsis." Molecular Biology of the Cell 23, no. 8 (April 15, 2012): 1446–56. http://dx.doi.org/10.1091/mbc.e11-09-0797.
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Mammalian nucleostemin (NS) is preferentially expressed in stem cells and acts to promote cell cycle progression. In plants, stem cell activities have to be terminated during flower development, and this process requires the activation of AGAMOUS (AG) gene expression. Here, a nucleostemin-like 1 gene, NSN1, is shown to be required for flower development in Arabidopsis. The NSN1 mRNA was found in the inflorescence meristem and floral primordia, and its protein was localized to the nucleoli. Both heterozygous and homozygous plants developed defective flowers on inflorescences that were eventually terminated by the formation of carpelloid flowers. Overexpression of NSN1 resulted in loss of apical dominance and formation of defective flowers. Expression of the AG gene was found to be up-regulated in nsn1. The carpelloid flower defect of nsn1 was suppressed by the ag mutation in the nsn1 ag double mutant, whereas double mutants of nsn1 apetala2 (ap2) displayed enhanced defective floral phenotypes. These results suggest that in the delicately balanced regulatory network, NSN1 acts to repress AG and plays an additive role with AP2 in floral organ specification. As a midsize nucleolar GTPase, NSN1 represents a new class of regulatory proteins required for flower development in Arabidopsis.
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López-Juárez, Zaira M., Laura Aguilar-Henonin, and Plinio Guzmán. "The ATXN2 Orthologs CID3 and CID4, Act Redundantly to In-Fluence Developmental Pathways throughout the Life Cycle of Arabidopsis thaliana." International Journal of Molecular Sciences 22, no. 6 (March 17, 2021): 3068. http://dx.doi.org/10.3390/ijms22063068.
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RNA-binding proteins (RBPs) are key elements involved in post-transcriptional regulation. Ataxin-2 (ATXN2) is an evolutionarily conserved RBP protein, whose function has been studied in several model organisms, from Saccharomyces cerevisiae to the Homo sapiens. ATXN2 interacts with poly(A) binding proteins (PABP) and binds to specific sequences at the 3′UTR of target mRNAs to stabilize them. CTC-Interacting Domain3 (CID3) and CID4 are two ATXN2 orthologs present in plant genomes whose function is unknown. In the present study, phenotypical and transcriptome profiling were used to examine the role of CID3 and CID4 in Arabidopsis thaliana. We found that they act redundantly to influence pathways throughout the life cycle. cid3cid4 double mutant showed a delay in flowering time and a reduced rosette size. Transcriptome profiling revealed that key factors that promote floral transition and floral meristem identity were downregulated in cid3cid4 whereas the flowering repressor FLOWERING LOCUS C (FLC) was upregulated. Expression of key factors in the photoperiodic regulation of flowering and circadian clock pathways, were also altered in cid3cid4, as well as the expression of several transcription factors and miRNAs encoding genes involved in leaf growth dynamics. These findings reveal that ATXN2 orthologs may have a role in developmental pathways throughout the life cycle of plants.
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Ziegler, Alfred M., and Eric D. Gyllenhaal. "Permian phytogeography and climate." Paleontological Society Special Publications 6 (1992): 329. http://dx.doi.org/10.1017/s2475262200008893.
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A greater number of floral provinces have been defined for the Permian than for any other Phanerozoic period, and this is presumably the reflection of a well differentiated set of climate zones. These floras have been assigned to an idealized set of ten “biomes” as defined on the basis of the equator-to-pole spectrum of present day climates (Ziegler, 1990). The biomes reflect temperature and precipitation, and in particular the way in which these parameters change through the annual cycle. The purpose of the present paper is (1) to expand the taxonomic database of Permian floras and climatically sensitive sediments, (2) to use ordination analyses and other multivariate techniques to relate taxonomic data to climate, geographic distance and other factors that controlled the global distribution of plants, and (3) to relate these results to the recognition of biomes during the Permian.This approach reveals that the phytogeographic provinces, as recognized by paleobotanists, are objectively valid entities, but significant gradations can be detected, supporting the idea that the floras were controlled by climate rather than by geographic separation. In fact, there are no examples in the Permian world of strictly geographic barriers, which is not surprising in view of the fact that the continents were basically together through this time.Biomes are defined by climatic parameters, but the taxonomic characteristics of biomes have evolved with time. The Permian floral provinces can be related to precipitation balance by their associations with such climatically sensitive sediments as coals, paleosols and evaporites, and this is critical for assigning each to an appropriate biome. At least at the generic level, taxonomic lists have significant limitations for identification of biomes in the geologic past. In particular, northern and southern hemisphere temperate biomes evolved radically different floras by the Permian. Ecomorphic characters and taxonomic diversity within critical groups may provide a more general scheme for phytologic recognition of biomes through geologic time.Finally, detailed comparisons will be made to General Circulation Model and Energy Balance studies on the Permian. The numerical studies seem to overemphasize the seasonal extremes of temperature in the middle to high latitudes.
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Schiessl, K., J. M. Muino, and R. Sablowski. "Arabidopsis JAGGED links floral organ patterning to tissue growth by repressing Kip-related cell cycle inhibitors." Proceedings of the National Academy of Sciences 111, no. 7 (February 4, 2014): 2830–35. http://dx.doi.org/10.1073/pnas.1320457111.
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Frank, M. C., and S. L. Bend. "Peat-forming history of the ancestral Souris mire (Palaeocene), Ravenscrag Formation, southern Saskatchewan, Canada." Canadian Journal of Earth Sciences 41, no. 3 (March 1, 2004): 307–22. http://dx.doi.org/10.1139/e04-002.
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Analysis of the Palaeocene Souris Lignite (northern Williston Basin) using coal petrology and palynology reveals the existence of seven different mire types forming six cycles of varying thickness and composition. The order of mire types within the individual cycles allows an idealized mire type succession to be defined. The principle factor driving the idealized mire type succession is decreasing water depth within the peat-forming environment (terrestrialization), which leads to an increase in species diversity and a change in floral character from ferns→ angiosperms→ gymnosperms. Increases in water depth are the primary agent responsible for the termination of individual cycles in the ancestral Souris mire. Changes in nutrient status of the mire may also promote major changes in the floral assemblage, contributing to cycle termination. Comparison of densinite:ulminite ratios for the central part of the Souris seam shows an overall decrease in the degree of humification south-westward, indicating increased subsidence towards the Williston Basin centre, where seam partings are more common. Fern-rich mire types dominate throughout most of the sampled part of the Souris seam and such mires have been interpreted as representing transitional stages in both modern and Tertiary peat-forming environments. Previous analysis of other parts of the Souris seam has revealed areas dominated by Taxodium forest mires, representing more stable environments. The co-existence of transitional and stable environments suggests that the ancestral Souris mire may have been deposited during the onset of the closing stages of Palaeocene peat formation in the northern part of the Williston Basin.
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Chouteau, Mathieu, Melanie McClure, and Marc Gibernau. "Pollination ecology of Monstera obliqua (Araceae) in French Guiana." Journal of Tropical Ecology 23, no. 5 (August 16, 2007): 607–10. http://dx.doi.org/10.1017/s0266467407004427.
Full textAbstract:
Data on pollination ecology of Araceae are still scarce and most concern species belonging to the subfamily Aroideae (García-Robledo et al. 2004, Gibernau 2003, Ivancic et al. 2004, 2005; Maia & Schlindwein 2006). In this subfamily, inflorescences consist of unisexual flowers: female flowers are located in the lower portion and the male flowers are in the upper portion of the inflorescence (Mayo et al. 1997). In the documented neotropical Aroideae, pollinators are nocturnal beetles and pollination mechanisms take place within a floral chamber during a short flowering cycle (generally 24–48 h) with floral rewards (sterile flowers rich in proteins and/or lipids) for the beetle pollinators, the secretion of resin to secure pollen on the pollinator, and the production of heat and odours (Chouteau et al. 2007, García-Robledo et al. 2004, Gibernau & Barabé 2002, Gibernau et al. 1999, 2000, 2003; Maia & Schlindwein 2006, Young 1986).
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Herz, Annette, Fabian Cahenzli, Servane Penvern, Lukas Pfiffner, Marco Tasin, and Lene Sigsgaard. "Managing Floral Resources in Apple Orchards for Pest Control: Ideas, Experiences and Future Directions." Insects 10, no. 8 (August 11, 2019): 247. http://dx.doi.org/10.3390/insects10080247.
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Functional biodiversity is of fundamental importance for pest control. Many natural enemies rely on floral resources to complete their life cycle. Farmers need to ensure the availability of suitable and sufficient floral biodiversity. This review summarizes 66 studies on the management of floral biodiversity in apple orchards, published since 1986. Approaches followed different degrees of intervention: short-term practices (mowing regime and weed maintenance, cover crops), establishment of durable ecological infrastructures (perennial flower strips, hedgerows) and re-design of the crop system (intercropping, agroforestry). Although short-term practices did not always target the nutrition of natural enemies by flowering plants, living conditions for them (alternative prey, provision of habitat) were often improved. Perennial flower strips reliably enhanced natural enemies and techniques for their introduction continuously developed. Resident natural enemies and their impact in pest control reacted positively to the introduction of a more diversified vegetation, whereas the response of very mobile organisms was often not directly linked to the measures taken. A careful selection and management of plants with particular traits exploitable by most natural enemies emerged as a key-point for success. Now the elaborated design of such measures needs to be adopted by stakeholders and policy makers to encourage farmers to implement these measures in their orchards.
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Lv, Xinchen, Xiaolin Zeng, Hongmiao Hu, Lixian Chen, Fan Zhang, Rui Liu, Yue Liu, et al. "Structural insights into the multivalent binding of the Arabidopsis FLOWERING LOCUS T promoter by the CO–NF–Y master transcription factor complex." Plant Cell 33, no. 4 (January 25, 2021): 1182–95. http://dx.doi.org/10.1093/plcell/koab016.
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Abstract Flowering plants sense various environmental and endogenous signals to trigger the floral transition and start the reproductive growth cycle. CONSTANS (CO) is a master transcription factor in the photoperiod floral pathway that integrates upstream signals and activates the florigen gene FLOWERING LOCUS T (FT). Here, we performed comprehensive structural and biochemical analyses to study the molecular mechanism underlying the regulation of FT by CO in Arabidopsis thaliana. We show that the four previously characterized cis-elements in the FT promoter proximal region, CORE1, CORE2, P1, and P2, are all direct CO binding sites. Structural analysis of CO in complex with NUCLEAR FACTOR-YB/YC (NF–YB/YC) and the CORE2 or CORE1 elements revealed the molecular basis for the specific recognition of the shared TGTG motifs. Biochemical analysis suggested that CO might form a homomultimeric assembly via its N-terminal B-Box domain and simultaneously occupy multiple cis-elements within the FT promoter. We suggest that this multivalent binding gives the CO–NF–Y complex high affinity and specificity for FT promoter binding. Overall, our data provide a detailed molecular model for the regulation of FT by the master transcription factor complex CO–NF–Y during the floral transition.
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Rajendran, Sujeevan, Jung Heo, Yong Jun Kim, Dae Heon Kim, Kisung Ko, Young Koung Lee, Seok Kwi Oh, Chul Min Kim, Jong Hyang Bae, and Soon Ju Park. "Optimization of Tomato Productivity Using Flowering Time Variants." Agronomy 11, no. 2 (February 4, 2021): 285. http://dx.doi.org/10.3390/agronomy11020285.
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The control of flowering time is a major contributing factor to the improvement of crop yield by optimizing plant growth in a crop cycle. Genetic variants that determine flowering time can provide insights into optimizing flowering time for higher yields and other beneficial traits in tomato crops. Here, we examined a collection of flowering time variants to assess their effects on biomass and total tomato yields. Five late flowering (lf), thirteen large plant (lp), and seven floral homeotic (fh) mutants were identified as flowering time variants that could be rearranged according to leaf production in the primary shoot meristem (PSM). A flowering time continuum of mutants was translated into a positive continuum of biomass yield with more leaves, branches, and floral organs. The flowering time continuum showed an optimal curve of fruit yield, indicating a certain late flowering time as optimal for fruit yield, with the yield gradually decreasing in both directions with earlier or later flowering times. We isolated lf1, lf10, lp22, and fh13 as high-yielding genotypes with optimal flowering time, showing a new balance between the vegetative and flowering phases of tomato. Additionally, lp8, fh8, and fh15 produced extremely high biomass in leaves, axillary shoots, and floral organs due to late flowering in shoot apices with additional production of floral organs and lateral shoot. Our new late-flowering variants provide new genetic resources that can be used to optimize crop yield by fine-tuning flowering time, and future molecular studies could be conducted by revisiting our yield model.
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Lee, Ze Hong, Takeshi Hirakawa, Nobutoshi Yamaguchi, and Toshiro Ito. "The Roles of Plant Hormones and Their Interactions with Regulatory Genes in Determining Meristem Activity." International Journal of Molecular Sciences 20, no. 16 (August 20, 2019): 4065. http://dx.doi.org/10.3390/ijms20164065.
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Plants, unlike animals, have developed a unique system in which they continue to form organs throughout their entire life cycle, even after embryonic development. This is possible because plants possess a small group of pluripotent stem cells in their meristems. The shoot apical meristem (SAM) plays a key role in forming all of the aerial structures of plants, including floral meristems (FMs). The FMs subsequently give rise to the floral organs containing reproductive structures. Studies in the past few decades have revealed the importance of transcription factors and secreted peptides in meristem activity using the model plant Arabidopsis thaliana. Recent advances in genomic, transcriptomic, imaging, and modeling technologies have allowed us to explore the interplay between transcription factors, secreted peptides, and plant hormones. Two different classes of plant hormones, cytokinins and auxins, and their interaction are particularly important for controlling SAM and FM development. This review focuses on the current issues surrounding the crosstalk between the hormonal and genetic regulatory network during meristem self-renewal and organogenesis.
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Ratcliffe, O. J., I. Amaya, C. A. Vincent, S. Rothstein, R. Carpenter, E. S. Coen, and D. J. Bradley. "A common mechanism controls the life cycle and architecture of plants." Development 125, no. 9 (May 1, 1998): 1609–15. http://dx.doi.org/10.1242/dev.125.9.1609.
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The overall aerial architecture of flowering plants depends on a group of meristematic cells in the shoot apex. We demonstrate that the Arabidopsis TERMINAL FLOWER 1 gene has a unified effect on the rate of progression of the shoot apex through different developmental phases. In transgenic Arabidopsis plants which ectopically express TERMINAL FLOWER 1, both the vegetative and reproductive phases are greatly extended. As a consequence, these plants exhibit dramatic changes in their overall morphology, producing an enlarged vegetative rosette of leaves, followed by a highly branched inflorescence which eventually forms normal flowers. Activity of the floral meristem identity genes LEAFY and APETALA 1 is not directly inhibited by TERMINAL FLOWER 1, but their upregulation is markedly delayed compared to wild-type controls. These phenotypic and molecular effects complement those observed in the tfl1 mutant, where all phases are shortened. The results suggest that TERMINAL FLOWER 1 participates in a common mechanism underlying major shoot apical phase transitions, rather than there being unrelated mechanisms which regulate each specific transition during the life cycle.
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Azizbekova, Naza Sh, Stefanie L. Butland, Brian E. Ellis, and Christia M. Roberts. "Cytological Examination of Scilla peruviana L. during a 20-month Cycle of Growth and Development." HortScience 33, no. 7 (December 1998): 1175–79. http://dx.doi.org/10.21273/hortsci.33.7.1175.
Full textAbstract:
The growth cycle of Scilla peruviana L. involved the development of two generations of daughter bulbs enclosed within each mother bulb. Flower initiation of the primary daughter bulb took place in June as the mother bulb apparently entered dormancy. Floral differentiation was complete by late October, by which time the apical meristem of the secondary daughter bulb had developed for 3 months inside the primary daughter bulb. The complete cycle of ontogenesis, from meristem initiation to flowering, occurred without interruption and required 20 months. Small zones of meristematic cells detected at the bases of bulb scales may be the origin of adventitious bulblets in this species. This detailed cytological study enabled the development of an effective commercial forcing program for S. peruviana.
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Wood, Bruce W. "Influence of Plant Bioregulators on Pecan Flowering and Implications for Regulation of Pistillate Flower Initiation." HortScience 46, no. 6 (June 2011): 870–77. http://dx.doi.org/10.21273/hortsci.46.6.870.
Full textAbstract:
Mitigation of alternate bearing (AB) through regulation of floral initiation of pistillate flowers is central to improving cropload management of pecan [Carya illinoinensis (Wangenh.) K. Koch] trees and orchards. The present study examines the influence of key bioregulators {i.e., an auxin [as B-napththaleneacetic acid (NAA)], a cytokinin [6-benylamino purine (6-BA)], an ethylene generator (ethephon), and an auxin transport inhibitor [2,3,5-triiodobenzoic acid (TIBA)]} on subsequent season pistillate flowering. Gibberellic acid (i.e., GA3) and NAA inhibited, whereas prohexadione–calcium (P-Ca; calcium 3-oxido-5-oxo-4-propionylcyclohex-3-enecarboxylate), ethephon, and BA + TIBA promoted floral initiation when topically applied to canopies before the kernel filling stage of seed development. These bioregulators exhibit potential for integration into a bioregulator-based strategy to mitigate pecan AB by selective and timely use in “off” or “on” cycle years, depending on the bioregulator. Field studies provide evidence that a “cytokinin–gibberellin balance,” with partial modulation by auxin and ethylene, acts in the endogenous primordial environment of floral meristems as a “second-level signal” regulating a key step in a three-step process for initiation of pistillate flowers in pecan. This establishes a new model for explaining pistillate flower initiation in pecan and a basis for designing future research on the control and management of pistillate flowering and AB.
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Coelho, Jobson Paixão de Amorim, Eliezer Santurbano Gervásio, Teógene Souza de Sá, Márkilla Zunete Beckmann Cavalcante, and Sabrina Gomes de Souza. "Management of tillering in the production of flower stems of heliconia cultivated in pots." Comunicata Scientiae 10, no. 3 (November 1, 2019): 353–63. http://dx.doi.org/10.14295/cs.v10i3.2716.
Full textAbstract:
Potted cultivation of tropical flowers presents good projections for the northeastern region of Brazil; however, it still faces some peculiarities regarding conduction and management. The objective of this study was to evaluate the effect of tillering on the production of Heliconia psittacorum L.f. cv. Red Opal, grown in flowerpot. The experiment was carried out in a protected environment at the Campus of Agricultural Sciences (CCA) of UNIVASF, Petrolina - PE, Brazil, between 2014 and 2016. A completely randomized design was used, with four tiller densities per pot (4, 8, 12 and 16 tillers) and eight replications, totaling 32 plots. The irrigation system was automated and monitored by weighing lysimetry. Were evaluated: efficiency of water use (EUA); harvested flower stems (HC); ratio of harvested stems and number of tillers (HC / NP); number of leaves (NF); duration of vegetative (DFV) and productive phases (DFP); total cycle (CT); floral stem length (CHF); floral stem diameter (DH), bracts length (CB) and equivalent diameter of the collar (DECH). The results were subjected to regression test. The EUA was higher in the density of 16 tillers pot-1; the HC variable presented an increasing linear trend; a decreasing linear trend was detected for HC/NP, NF, DFP, DH, CB and DECH. The number of tillers in the pot does not limit the emission of floral stems. However, the quality of these is inversely proportional to the tiller density.
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Gonthier, R., A. Jacqmard, and G. Bernier. "Changes in cell-cycle duration and growth fraction in the shoot meristem of Sinapis during floral transition." Planta 170, no. 1 (January 1987): 55–59. http://dx.doi.org/10.1007/bf00392381.
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Posluszny, Usher, and Jean M. Gerrath. "The vegetative and floral development of the hybrid grape cultivar ‘Ventura’." Canadian Journal of Botany 64, no. 8 (August 1, 1986): 1620–31. http://dx.doi.org/10.1139/b86-218.
Full textAbstract:
The vegetative and floral development of the hybrid grape cultivar ‘Ventura’ was studied. A tendril forms opposite the last-formed leaf on the shoot but is slightly delayed in its initiation. Six nodes and 10 primordia complete one leaf–tendril initiation cycle. The inflorescence develops at the same site and is initially indistinguishable from the tendril. Inflorescence primordia are initiated on the upper arm, first opposite each other in a decussate arrangement and then apparently spirally. Each inflorescence primordium may subsequently initiate two lateral primordia, which become subtended by bracts. These in turn may repeat the pattern so that ultimately third- or fourth-order cysmose inflorescence branches may be produced. During floral development the calyx is initiated at first as three primordia, followed by a ring, which ultimately develops five lobes. The five corolla primordia alternate with the sepals. The five stamen primordia are initiated opposite the petals. The gynoecium initiates as five primordia, which later become a ring. Two septae are initiated opposite each other on the inner flank of the ring, forming the two-loculed ovary. Each septum forms a placenta, giving rise to two ovules. The upper portion of the gynoecial ring grows up over the ovules and forms the short style and discoid stigma.