Dissertations / Theses on the topic 'Panicle development'

The transition from a vegetative phase to a reproductive one has always been deeply studied in plants and in particular in the cereals due to the relevance of this trait for seed yield. The transition occurs upon the arrival of a mobile flowering signal, the florigen, at the shoot apical meristem (SAM). In rice (Oryza sativa), there are two different florigens: Heading Date 3a (Hd3a), that promotes flowering in short day (SD) conditions and Rice Flowering Locus T 1 (RFT1) that promotes flowering in both short and long- days (LD). They are transcribed and translated in leaves once environmental conditions are optimal, and then transported through the phloem to the SAM. After reaching the shoot they form a heterohexameric complex named Florigen Activation Complex (FAC) binding to two 14-3-3 proteins and to two bZIP transcription factors and activate conversion of the shoot apex into an inflorescence by promoting expression of inflorescence- identity genes. Here, we show that Hd3a and RFT1 arrival at the SAM activates FLOWERING LOCUS T-LIKE 1 (FT-L1), encoding a third florigen-like protein showing atypical characteristics. Expression data from qRT-PCR, in situ hybridization and transcriptional marker lines indicated that its mRNA is mainly expressed in the SAM and persists during all developmental stages of inflorescence development. Misexpression of FT-L1 from meristem- and tissue-specific promoters indicates that only when expressed in the SAM, FT-L1 has florigenic activity. Isolation and analysis of EMS and CRISPR mutants showed that FT-L1 strengthens the effects of Hd3a and RFT1 during conversion of the vegetative meristem into inflorescence, in an addictive manner. Furthermore, it controls panicle branching by inhibiting secondary branching and promoting spikelet meristem differentiation. Thus, we propose a triple florigenic module that promotes a balanced progression of inflorescence identity and determinacy.

<p>Much of plant growth is directly or indirectly regulated by the plant hormone auxin. Although some genes involved in the auxin pathway have been characterized, there are still gaps in our knowledge of this genetic pathway. Recently, the orthologous maize genes <i>BARREN STALK2</i> (<i> BA2</i>) and rice gene <i>LAX PANICLE2</i> (<i>LAX2</i>) have been cloned and characterized. Maize <i>ba2</i> and rice <i> lax2</i> mutant plants both show significant flaws in axillary meristem (AM) initiation, suggesting a role in auxin regulation. In support of this hypothesis, <i>LAX2</i> interacts with the auxin regulating <i> LAX PANICLE1</i> (<i>LAX1</i>) protein. My research reconstructs the evolutionary history of the <i>BA2</i>/<i>LAX2</i> lineage and tests for conservation of <i>BA2</i>/<i>LAX2</i> mRNA expression in diverse grasses. My results indicate that the <i> BA2</i>/<i>LAX2</i> gene family&mdash;comprising <i>BA2 </i>/<i>LAX2</i>, <i>BA2</i>/<i>LAX2-Like1</i> (<i>BA2</i>/<i>LAX2L1</i>), and <i>BA2</i>/<i> LAX2-Like2</i> (<i>BA2</i>/<i>LAX2L2</i>)&mdash;is restricted to monocots, and shows evidence of two independent gene duplication events. During its evolution, the <i>BA2</i>/<i>LAX2</i> gene family appears to have gained a PDZ Protein Binding motif, which may allow it to interact with other proteins besides <i>BA1</i>/<i> LAX1</i>. My expression analyses show that <i>BA2</i>/<i> LAX2</i> genes are expressed during multiple stages of inflorescence development, and this expression is conserved across multiple grass species. A unique floral expression pattern appears to have evolved at the base of the Joinvilleaceae lineage. My study further supports the hypothesis that <i> BA2</i>/<i>LAX2</i> genes are functioning in multiple AM pathways. </p>

Excessive use of fossil fuels to meet everyday energy demands has led to adverse environmental impacts like global warming and high dependence on foreign oil. Development of cellulosic feedstocks provides energy security and also reduces the burden on food crops like corn and sugarcane used for ethanol production. This thesis uses cost-benefit analysis to ascertain the profitability of producing cellulosic ethanol from Switchgrass and Sweet Sorghum Bagasse. First, breakeven price of producing Switchgrass and Sweet Sorghum is calculated to obtain a raw material (feedstock) cost for ethanol production. Next, net present value (NPV) and minimum ethanol selling price (MESP) for Switchgrass and Sweet sorghum are calculated. Lastly, risk analysis is performed and its impacts on NPV are calculated for two farmer categories. The results show that ethanol production from Switchgrass and Sweet Sorghum is commercially feasible and generates a Net Present Value (NPV) of $39.54 million for Switchgrass and $96.76 million for Sweet Sorghum at an ethanol selling price of $2.17 per gallon. At NPV zero the MESP for Switchgrass and Sweet Sorghum is estimated to be $2.10 and $1.96 per gallon respectively. The risk analysis results revealed that there is a 9.5 percent probability that the NPV for a risk-averse Switchgrass farmer will be less than zero. On the other hand, the probability of the NPV being less than zero is 67.4 percent. The overall analysis indicates that ethanol production from Switchgrass and Sweet Sorghum is a promising option. Reduction in feedstock prices, optimization of the conversion process and additional revenues from by-products can make cellulosic ethanol more competitive with current gasoline prices.<br>Master of Science

This thesis presents the current analysis technique applied to certain psychology data and outlines alternative engineering approaches to such analysis. Current research on panic disorder involves data measurement and analysis of many physiological, neuro-chemical and psychological variables. Due to the complexity of and little knowledge about the human body, there are no firm theories on what actually gives rise to these variables, ie. what results in a rise in negative cognition or distress level. Current studies [1, 2] have reported that the patients cognitive responses tend to be more closely related to the distress level than other quantities and the heart rate is related to the distress level but on a smaller scale. However, the conclusions drawn from the results were not definitive. Engineering analysis techniques carried out indicated that the cognitions of the patients play an important role in the mechanisms of panic. This thus confirmed the results obtained by current studies in a more rigorous manner.

This study combines moral panic with the figurational sociology of Norbert Elias to explore how climate change has developed as a social problem. The central argument is that,through combining the short-term focus of moral panic with the long-term focus of Elias, we can examine the interplay between planned and unplanned developments in both the perception and reality of climate change. The first part of the research consisted of discourse analysis of a variety of different texts from 1800 to the present. These were used to explore the long-term development of climatechange as emerging from an ecological civilizing process. The second stage of the research related these developments to moral panics, arguing that the emergence of climate change can only be understood by exploring the interplay between long-term processes and short-term campaigns. The third part of the research explored these historical developments at the individual level, examining the notion of individual ecological civilizing processes. 15 semi-structured interviews were undertaken with climate change ‘activists’ and ‘non-activists’, comparing how their biographical developments related to ecological civilizing processes and moral panics. The final part of the research compared climate change with five other empirical examples of moral panics, to explore the civilizing and decivilizing processes and civilizing offensives that occur before, during, and after the panics. The central aim was to demonstrate the complexity of moral panics, and to aid in the reformulation of the concepts of moral panic and decivilization. Through a synthesis of Elias and moral panic, as applied to the example of climate change, this study aimed to: critically assess the development of climate change; to reassess the concept of decivilization and the relation between civilizing processes and offensives; and to reformulate the concept of moral panic, including suggesting how moral panic research ought to be undertaken.

To decrease dependency of fossil fuels and avoid direct competition with food crops, massive research efforts are investigating next-generation cellulose biofuel crops such as switchgrass (Panicum virgatum). A low-input, sustainable switchgrass production could be achieved by reducing traditional management practices though applying plant growth promoting rhizobacteria (PGPR), of which our understanding is still rather limited. To elucidate physiological mechanisms behind PGPR's beneficial effects, we inoculated switchgrass seedlings with Burkholderia phytofirmans strain PsJN. Two experiments were conducted to determine the initial and long-term responses of switchgrass to PsJN inoculation by tracking growth and leaf physiology. In a third experiments, we tested the effects of PsJN on growth and leaf-level physiology of switchgrass under a moderate pre-drought conditioning and a successive severe drought stress. PsJN inoculation increased biomass and promoted elongation of shoots within 17 days following inoculation. The enhanced root growth in PsJN inoculated plants lagged behind the shoot response, resulting in greater allocation to aboveground growth (p=0.0041). Lower specific root length (p=0.0158) and higher specific leaf weight (p=0.0029) were also observed in PsJN inoculated seedlings, indicating advanced development. Photosynthetic rates (Ps) were higher in PsJN inoculated seedlings after 17 days (54%, p=0.0016), which were related to higher stomatal conductance, greater water use efficiency, and lower non-stomatal limitation of Ps. These rapid changes in leaf physiology are at least partially responsible for switchgrass growth enhancement from PsJN treatment. The early growth enhancement in PsJN inoculated switchgrass linearly decreased with plant age. PsJN inoculation increased Ps of upper canopy leaves by 13.6% but reduced Ps of lower canopy leaves by 8.2%. Accelerated leaf senescence and early flowering were observed in PsJN-inoculated switchgrass, which might contribute to slightly lower aboveground biomass at final harvesting. Drought preconditioning increased Ps of PsJN-inoculated switchgrass during a later severe drought; whereas, control switchgrass only benefited from drought preconditioning when leaf water potential dropped below -1 MPa. This study verified early growth enhancement and accelerated development of switchgrass due to PsJN inoculation. Rapid improvement in leaf physiology is related to enhanced productivity. PsJN inoculation also improve drought tolerance of switchgrass.<br>Ph. D.

Objective: To examine the association between separation anxiety disorder (SAD) and mental disorders in a community sample and to evaluate whether separation anxiety is specifically related to panic disorder with and without agoraphobia. Method: The data come from a 4-year, prospective longitudinal study of a representative cohort of adolescents and young adults aged 14–24 years at baseline in Munich, Germany. The present analyses are based on a subsample of the younger cohort that completed baseline and two follow-up investigations (n = 1,090). DSM-IV diagnoses were made using the Munich Composite International Diagnostic Interview. Cox regressions with time-dependent covariates were used to examine whether prior SAD is associated with an increased risk for subsequent mental disorders. Results: Participants meeting DSM-IV criteria for SAD were at an increased risk of developing subsequent panic disorder with agoraphobia (PDAG) (HR = 18.1, 95% CI = 5.6–58.7), specific phobia (HR = 2.7, 95% CI = 1.001–7.6), generalized anxiety disorder (HR = 9.4, 95% CI = 1.8–48.7), obsessive-compulsive disorder (HR = 10.7, 95% CI = 1.7–66.1), bipolar disorder (HR = 7.7, 95% CI = 2.8–20.8), pain disorder (HR = 3.5, 95% CI = 1.3–9.1), and alcohol dependence (HR = 4.7, 95% CI = 1.7–12.4). Increased hazard rates for PDAG (HR = 4.2, 95% CI = 1.4–12.1), bipolar disorder type II (HR = 8.1, 95% CI = 2.3–27.4), pain disorder (HR = 1.9, 95% CI = 1.01–3.5), and alcohol dependence (HR = 2.1, 95% CI = 1.1–4.) were also found for subjects fulfilling subthreshold SAD. Conclusions: Although revealing a strong association between SAD and PDAG, our results argue against a specific SAD-PDAG relationship. PDAG was neither a specific outcome nor a complete mediator variable of SAD.

Objective: To examine the association between separation anxiety disorder (SAD) and mental disorders in a community sample and to evaluate whether separation anxiety is specifically related to panic disorder with and without agoraphobia. Method: The data come from a 4-year, prospective longitudinal study of a representative cohort of adolescents and young adults aged 14–24 years at baseline in Munich, Germany. The present analyses are based on a subsample of the younger cohort that completed baseline and two follow-up investigations (n = 1,090). DSM-IV diagnoses were made using the Munich Composite International Diagnostic Interview. Cox regressions with time-dependent covariates were used to examine whether prior SAD is associated with an increased risk for subsequent mental disorders. Results: Participants meeting DSM-IV criteria for SAD were at an increased risk of developing subsequent panic disorder with agoraphobia (PDAG) (HR = 18.1, 95% CI = 5.6–58.7), specific phobia (HR = 2.7, 95% CI = 1.001–7.6), generalized anxiety disorder (HR = 9.4, 95% CI = 1.8–48.7), obsessive-compulsive disorder (HR = 10.7, 95% CI = 1.7–66.1), bipolar disorder (HR = 7.7, 95% CI = 2.8–20.8), pain disorder (HR = 3.5, 95% CI = 1.3–9.1), and alcohol dependence (HR = 4.7, 95% CI = 1.7–12.4). Increased hazard rates for PDAG (HR = 4.2, 95% CI = 1.4–12.1), bipolar disorder type II (HR = 8.1, 95% CI = 2.3–27.4), pain disorder (HR = 1.9, 95% CI = 1.01–3.5), and alcohol dependence (HR = 2.1, 95% CI = 1.1–4.) were also found for subjects fulfilling subthreshold SAD. Conclusions: Although revealing a strong association between SAD and PDAG, our results argue against a specific SAD-PDAG relationship. PDAG was neither a specific outcome nor a complete mediator variable of SAD.

碩士<br>國立中興大學<br>分子生物學研究所<br>103<br>The T-DNA mutant M52048 identified from Taiwan Rice Insertional Mutant (TRIM) library showed dwarf, early flowering, node bending and impaired in panicle exertion. Three flanking genes, OsMADS34, OsMADS14 and OsCP7 (putative cysteine protease 7) were activated in this mutant. Both OsMADS34 and OsMADS14 belong to MADS-box gene family that may participate in regulation of flowering time and the identity of floral organ. OsCP7 encode a putative cysteine protease, belongs to C1A cysteine protease family, its function remains unknown. In this study the function of OsMADS34 and OsCP7 were further investigated. Previous study showed that over-expression of OsMADS34, Ubi:OsMADS34 transgenic rice, could cause slightly early flowering and impaired in panicle exertion. Morphological dissection indicated that the impaired in panicle exertion was mainly caused by shortening the first internode (peduncle). Inhibition of the peduncle elongation caused by drought stress and ABA accumulation has been reported. In the present study, some drought-related genes, such as DREB1A, DREB1E and EATB, were regulated in Ubi:OsMADS34 transgenic rice and therefore hypothesized that the phenotype of transgenic rice may regulated by drought stress or plant hormones. However, treated transgenic rice with ABA inhibitor and/or GA could not improve the peduncle elongation and panicle exertion, suggested that the shortened peduncle and impaired in panicle exertion in Ubi:OsMADS34 transgenic rice might not cause by ABA accumulation. Analysis of GA biosynthesis related genes and the cell elongation promoting genes, at the internodes, revealed high expression levels of EATB, EUI1, GA13ox1, GA20ox2, OsPK1 and lower expression of XTH28, suggested that the shortened internode might due to the imbalance expression of these genes. However the mechanism how these genes involved in internode elongation remain to be elucidated. In addition to the shortened peduncle, the anther development was also affected in Ubi:OsMADS34, suggesting that OsMADS34 function as an E class MADS-box gene may interact with other MADS-box genes to regulate the floral organ development. Further study by searching OsMADS34 interaction proteins will help us to unravel the possible function of OsMADS34. For the study of OsCP7 gene, we were unable to obtained stable transgenic rice lines with constitutive promoter constructs, suggesting that constitutively ectopic expression of OsCP7 might cause lethal. Instead, transgenic lines with a 1.6 kb of OsCP7 promoter construct, OsCP7:OsCP7, were successfully obtained. OsCP7:OsCP7 revealed slightly dwarf, delayed flowering, lesion-like spots on panicles and lower fertility, and these phenotypes are correlated to the expression of OsCP7 gene. The possible mechanisms that cause these aberrant panicle developments were under investigated.

碩士<br>國立中興大學<br>分子生物學研究所<br>101<br>M52048 is a rice mutant with T-DNA insertion which activated flanking genes OsMADS14, OsMADS34 and OsCP7, resulting in darwf, early flowering, node bending and impaired panicle exertion. OsMADS14 and OsMADS34 belong to MADS-box gene family, can regulate the flowering time and the floral meristem development. OsMADS14 regulate the flowering time and has been well studies. OsMADS34 has been known to regulate the floral meristem development and panicle branching, OsCP7 encodes a putative cysteine protease, but the function by overexpressing OsMADS34 and OsCP7 genes remained unknown. The OsMADS34 overexpressing transgenic rice, Ubi:OsMADS34, revealed early flowering and impaired in panicle exertion. Morphological dissection indicated that the impaired panicle exertion was caused by shortening the first and second internodes. Previous study showed drought stress inhibited panicle exertion by reducing the peduncle elongation during flowering and induced the accumulation of ABA. The present study showed some dorught-related genes and miRNAs were regulated in Ubi:OsMADS34, and therefore, hypothesized that the phenotype of Ubi:OsMADS34 may regulated by drought stress or plant hormones. However, ABA inhibitor and GA treatments in this study could not improve the first internode elongation and panicle exertion. Gene expressinon analysis indicated the GA-regulated gene, EATB, was up-regulated and cell elongation promoting genes, XTH19 and XTH28, were reduced in the first and second internodes of Ubi:OsMADS34, suggesting that the limited internode elongation may be due to the differential expression of these internode regulating genes. However, how these genes were regulated remains further elucidation. OsCP7, like a typical cysteine protease, consist of a signal peptide, a prodomain and a protease domain, expressed in vegetative tissues but not in reproductive tissues. No OsCP7 overexpressing transgenic rice driven by ubiquitin or 35S promoters was stably obtained, though few of them could survive in the medium. Instead of these consititutive promoters, a 1.6 kb promoter fragment of OsCP7 could drive the expression of OsCP7 in rice successfully. This 1.6 kb OsCP7 promoter-driven transgenic rice, OsCP7:OsCP7, showed slightly dawrf, delayed flowering, low pollen viabillity, lower fertility seeds, and lesion-like brown spots appeared on spikelet. The lesion-like spots were first occuerd on the outer surface of spikelet when exposed to sunlight after heading. The spots could spread quickly in days and led to extensive cell death with ROS accumulation. However, using RNAi approach to knockdown the expression of OsCP7 did not show any specific phenotype. Further investigation to understand the molecular mechanism of the formation of the lesion-like spot is underway.

LFY of Arabidopsis is a member of a unique plant specific transcription factor family. It is involved in giving meristem a determinate floral fate by the activation of floral organ identity genes and preventing inflorescence meristem identity. RFL is a homolog of FLO/LFY in rice. Studies from our lab on rice RFL, based on the effects of knockdown or overexpression, showed its major functions are in timing the conversion of SAM to IM and to prevent the premature conversion of branch meristem to spikelets. Additionally roles in vegetative axillary meristem specification have been also been identified in laboratory. Here, we attempt to delineate molecular pathways directly regulated by RFL as a transcription factor controlling inflorescence and floral development in rice. Part I: Identification of global target genes bound by RFL in developing rice inflorescences We carried out ChIP sequencing of the DNA bound by RFL in panicles (01.-0.3cm stage) using anti-RFL antibody. DNA sequences in one library pool were analyses by the MACS algorithm (FDR<0.01), to find 8000 binding sites while the SPP algorithm identified 5000 enriched peaks. These mapped to 2500 or 2800 gene-associated loci respectively, 617 of which were common loci to both pipelines. Several RFL bound gene loci were homologs of Arabidopsis thaliana LFY gene targets. Such gene targets underscore conserved downstream targets for LFY-proteins in evolutionarily very distinct species. AtLFY is known to bind variants of CCANT/G cis element classified as primary, inflorescence or seedling type. We scanned for these three types of cis elements at 123 RFL bound genes with likely functions in flowering. For a few of these 123 rice loci we find one of these cis motifs (p-value<0.001) in RFL bound ChIP-seq data. To validate these targets of RFL, we adopted in vitro DNA-protein binding assays with bacterially purified RFL protein. We confirm RFL target interactions with some genes implicated in flowering time, others in photoperiod triggered flowering, circadian rhythm, gibberellin hormone pathway, inflorescence development and branching. The in vitro experiments hint different RFL-DNA binding properties as compared to Arabidopsis LFY. We report binding to sequences at rice gene loci that are unique targets. Part II: Pathways regulated by RFL for reproductive transition and panicle development To co-relate DNA binding of RFL to target loci with changes in their gene expression, expression studies were taken up for selected set of genes implicated in rice flowering transition and panicle architecture. To study in planta and tissue specific gene regulation by RFL we raised RFL dsRNAi transgenics. Comparative transcript analysis in these RFL partial knockdown lines and matched wild type tissues reveal that RFL is an activator for some genes and repressor for other gene targets. We also examined if the gene expression effects of RFL knockdown can be reversed by induced complementation with an RFL-GR protein. We raised transgenics plants with a T-DNA ubi:RFL-GR, 35S CaMV:amiR RFL for these experiments. In planta target gene transcript levels were assessed in various conditions conditions. These studies validate rice RFL as an activator of some panicle architecture genes. Part III: Analysis of endogenous RFL protein in WT rice tissues Studies in Arabidopsis and in petunia with LFY and AFL, respectively, implicate these some abnormal mobility as compared to their predicted molecular weight when overexpressed. We studied endogenous RFL protein abundance in planta, adopting western analysis with anti-RFL antibody. We consistently identify two prominent cross reacting bands in different tissues which can be also be pulled-down from whole nuclear extracts of panicle and axillary meristem tissues. We speculate on likely modifications and possible functions for the same.

碩士<br>國立屏東科技大學<br>熱帶農業暨國際合作系<br>101<br>Drought is one of the most serious environmental factors that negatively affect rice production; when it occurs at panicle initiation stage, it results in dramatic reduction of spikelet fertility and grain yield. The results indicated that spikelet sterility under drought is triggered by deficient plant water status that inhibited panicle differentiation and flowering. Two rice varieties, Indica and Japonica, were grown in a lowland field and in P-house under different water levels. Well-watered treatments consisted of two treatments; one was to keep the soil flooded up to 10 cm and the other one was to keep the soil moisture at 100% field capacity (FC) treatment respectively. Irrigation was applied using a continuous irrigation system throughout the experiment to the well-watered treatments, and the drought stress treatment was initiated differentially from panicle initiation to heading stage. Drought treatments consisted of holding the volume soil moisture at 25.67% (i.e., 70% FC) and 16.50% (i.e., 40% FC) for mild stress and severe stress respectively. Photosynthesis rate was significantly affected under drought stress compared to well-water treatments whereas proline content was significantly higher under stress conditions compared to well-water treatment. Therefore, the photosynthesis rate was 144.5 nmol O2 /cm2/h under drought treatment and 260.08 nmol O2 /cm2 /h under well-watered treatment in the field whereas it was 132.54 nmol O2 /cm2/h under drought treatment and 246.37 nmol O2 /cm2/h under well-watered treatment in the P-house experiment. However, the accumulation rate of proline was associated with the severity of drought and it varied from 0.57, 0.62 and 0.68 μmol /g fw under well-watered treatment, and 4.58, 4.85 and 5.22 μmol /g fw under drought in the field experiment at panicle initiation, booting and heading stages respectively. Similarly, it varied from 0.64, 0.76 and 0.78 μmol /g fw under well-watered treatment, and 5.19, 5.74 and 6.49 μmol /g fw under drought treatment in P-house experiment at panicle initiation, booting and heading stages respectively. Panicle number was significantly affected by drought, simultaneously with the decrease of plant water status parameters leading to important yield reduction. In P-house experiment, the highest value of panicle number (24.20) was found in flooded treatment followed by 100% FC treatment (20.60), mild stress (18.06) and severe stress (3.67) respectively. Panicle dry weight, filled grain dry weight and yield were significantly higher in the irrigated treatments than in drought stress treatments. Thousand grain (1000-grain) weight of all the irrigated treatments were heavier (24.5 g) than that of the drought (18.3 g) in P-house similarly it were heavier (26.8 g) in irrigated treatment than it was under drought (22.5 g). Drought stress substantially reduced grain yield, and the average yield in mild stress treatment was only 40% of that of 100% FC treatment in the field experiment, and the average yield in severe stress was only 20% of that of the saturated treatment. Furthermore, average yield of flooded treatment was only 65% of that of 100% FC treatment. In P-house experiment, yield was highly associated with leaf dry weight (R2=0.66**), panicle dry weight (R2=0.93***), biomass production (R2=0.91***) and polished rice (R2=0.93***). The sensitivity during panicle initiation to drought stress, as determined by the agronomic traits and yield components, was significantly different between varieties and among treatments. The results also showed the number of tillers per hill was decreased with decreased soil moisture level. Number of filled grain per panicle has been reduced under drought, but the highest amount (179.20) was found under well-watered treatment compared to drought treatment (143.3) in the field. Similarly, well-watered treatments exhibited higher number of grain per panicle (160.35) than drought treatments (147.62) in P-house experiment. Subsequently, Indica type exhibited higher tolerance to drought stress than Japonica type. The analysis revealed that drought stress had negative effects on yield, whereas 100% field capacity exhibited a major positive effect on yield followed by flooded treatment. Panicle initiation had a high and negative indirect effect on yield under drought through spikelet fertility. It is concluded that panicle initiation is the most sensitive growth stage that affects rice yield through the increase of spikelet sterility under drought stress.

<div>Switchgrass (Panicum virgatum L.) is an important warm-season perennial grass in livestock systems and has been extensively researched as an herbaceous energy crop. Objectives of this series of studies were to compare morphological development, compositional quality, crop growth, and yield of a recently developed biofuel cultivar ‘Liberty’ to an improved forage cultivar ‘Shawnee’ in multiple Indiana environments. Pure stands of each cultivar were sampled in the field at Trafalgar and Roann, Indiana in 2016. In 2017, samples were collected at Trafalgar, Roann, and Lafayette, Indiana. Samples were collected weekly during the early season and every other week in the late season with development determined by use of the Mean Stage Count (MSC) and Mean Stage Weight (MSW) system.</div><div>In the morphological development study, MSC and MSW were linearly related to both GDD and DOY for both years. ‘Liberty’ growth lagged behind ‘Shawnee’ throughout the whole growing season by approximately seven days. Prediction equations for MSC and MSW were developed based on accumulated GDD and DOY for Trafalgar and Roann in 2017. The prediction equations for MSC as predicted by GDD explained from 84 to 93 percent of the variation in MSC across locations for ‘Shawnee’ and between 90 to 94 percent of the variation for ‘Liberty’. For MSW, ‘Shawnee’ and ‘Liberty’ prediction equations explained from 84 to 93 percent and 90 to 95 percent of the variation as predicted by GDD across locations, respectively.</div><div><br></div><div>In the compositional quality study, samples from every other sampling date were ground and analyzed using near-infrared reflectance spectroscopy (NIRS). Increasing nitrogen fertilizer caused a higher nitrogen concentration at a given MSC. The 0 kg N ha-1 fertilizer rate dropped below 10 mg g-1 nitrogen by MSC 2.2, whereas the 134 kg N ha-1 fertilizer rate had greater than 10 mg g-1 until MSC 2.7. ‘Liberty’ had increased Neutral Detergent Fiber (NDF) concentration as compared to ‘Shawnee’. For whole-plant samples, ‘Liberty’ averaged 727 mg g-1 NDF as compared to ‘Shawnee’ which averaged 718 mg g-1. ‘Liberty’ had 18 mg g-1 higher acid detergent fiber (ADF), on average, as compared to ‘Shawnee’. Acid Detergent Lignin (ADL) was not different among nitrogen fertilizer treatments. Stem-plus-sheath material accounted for a higher percentage of NDF, ADF, and ADL, in whole-plants as MSC increased, as compared to leaf blades. ‘Shawnee’ had higher IVDMD as compared to ‘Liberty’ and the biggest differences occurred around MSC 2.9. At MSC 2.9, ‘Shawnee’ whole-plant IVDMD was 448 mg g-1 and ‘Liberty’ whole-plant IVDMD was 430 mg g-1. Whole-plant ash concentration decreased as MSC increased.<br></div><div><br></div><div>For the study that evaluated crop growth and yield, differences in grams m-2, mass tiller-1, and tiller number per unit area were analyzed in response to growing degree days (GDD) and day of year (DOY). Number of tillers had a negative linear response to GDD and DOY for both years, whereas, mass tiller-1 had a positive linear response to GDD and DOY for both years. Grams m-2 responded quadratically to GDD and DOY. Generally, ‘Liberty’ had 20 percent higher mass tiller-1 and lower number of tillers per m-2 at the end of the season as compared to ‘Shawnee.’ Addition of nitrogen fertilizer generally increased mass tiller-1 and grams m-2. Roann, the northern most site, also had highest tiller numbers at the beginning of the season and decreased faster than at the central Indiana sites. ‘Liberty’ yielded 8.8 percent higher than ‘Shawnee’ across locations, nitrogen rates, and sampling years. Addition of nitrogen fertilizer did not conclusively increase yield. Grams m-2, mass tiller-1, and tillers per sample area helped explain some yield differences. For example, ‘Liberty’ had increased yield as compared to ‘Shawnee’, and ‘Liberty’ also had higher mass tiller-1 with no differences in tiller number between cultivars. While additions of nitrogen fertilizer increased grams per tiller, yield was not significantly increased with added nitrogen fertilizer. Therefore, these measures should not stand alone as a predictor of yield differences between cultivars. Switchgrass is a bunchgrass and has inherent difference in numbers of plant and tillers per plant within a plot, which may not be truly represented by one crop growth parameter alone.</div><div><br></div><div>This study confirms that switchgrass has great potential as a forage and biofuel crop in Indiana with low nitrogen fertilizer requirements and high yield. Understanding how switchgrass morphological development, compositional quality, growth, and yield responds in Indiana environments across locations, years, and nitrogen rates will help guide the future switchgrass management decisions of producers and researchers.</div>

碩士<br>國立臺灣大學<br>新聞研究所<br>103<br>As Taiwan’s medical work environment begins to worsen, it is starting to push its medical worker to leave the country in search of better work opportunities and environment. Media reports that there has been a trend of corporate hospitals from Mainland China poaching the skilled Taiwan’s physician with competitive high salaries. As the progression and development of a health care worker takes much more than just an individual contribution and cost factor, it also takes the combined efforts from the country and society. With the leaving of these Taiwanese trained physicians to Mainland China, they may appear to be working under a similar culture and same language system. However, they are in a different institutional system, their occupational life is bound to be impacted. How should these professionals adapt to the differences? Unfortunately, with regards to this matter, media is rarely reporting it. This in-depth report is base on the above question. It would focus on the development after the big move to China. Upon the lure to move on to a country with the possibility of profiting from this mega population of 1.3 billion people. Did these Taiwanese physicians finally succeeded in getting a share in this booming industry? Or has it been just a dream after all? In order to find the answer, this thesis presents finding from Taiwan’s physician who practice in Mainland China. It will be focusing on the comparison of medical system, physician-patient relationship etc. For this report, I had interviewed around thirty physicians and related respondents. Through face-to face interview, I would be asking them to share with me on the difficulties that they faced throughout this move. With substantial findings and data, I had analyzed and provided suggestions. Taiwanese physicians may have a hard time adapting when they practice in Mainland China. This would includes: The unequal of physician title in both cross-strait medical environment, according to the law governing Taiwan’s physicians, they are not allowed to do surgeries if they do not hold the related title. Taiwanese physicians may also face difficulty when it comes to Job progression or promotion. There is also the issue that China’s physician social status is inferior as compared to Taiwan. Furthermore, it is hard to operate a privatized hospital and come in contact with high-end private patient. Moreover, different working method would create friction. Also, the physician-patient relationship is different from that in Taiwan. The above are the common obstacles that Taiwanese physicians faced while they practiced in China, resulting in them giving up their career in China, and returning home to Taiwan. Nevertheless medical demand is still bigger than supply in China. Taiwanese physicians survive in China are based on three elements: manage the medical business on your own, invest money to build up on hardware and software, and build up contacts and to ensure that they have the ability to attract more patients. At this present moment, Taiwan may still be at an advantage in the medical profession, but with the huge number of talents from China, Many has predicted that China would surpass Taiwan within the next three to five years. Therefore, if Taiwanese physicians don’t create a self-survival rule, it will be difficult for them to gain a foothold.