scholarly journals Mechanistic model of temperature influence on flowering through whole-plant accumulation of FT

2018 ◽  
Author(s):  
Hannah A. Kinmonth-Schultz ◽  
Melissa J. MacEwen ◽  
Daniel D. Seaton ◽  
Andrew J. Millar ◽  
Takato Imaizumi ◽  
...  
Keyword(s):  
Temperature Regulation ◽  
Leaf Growth ◽  
Mechanistic Model ◽  
Day Length ◽  
Temperature Influence ◽  
Leaf Production ◽  
Photoperiodic Flowering ◽  
Whole Plant ◽  
Improve Model ◽  
Flowering Regulator

AbstractWe assessed temperature influence on flowering by incorporating temperature-responsive flowering mechanisms across developmental age into an existing model. Temperature influences both the leaf production rate and expression of FLOWERING LOCUS T (FT), a photoperiodic flowering regulator, in leaves. The Arabidopsis Framework Model incorporated temperature influence on leaf growth but ignored the consequences of leaf growth on and direct temperature influence of FT expression. We measured FT production in differently aged leaves and modified the model, adding the mechanistic temperature influence on FT transcription, and linking FT to leaf growth. Our simulations suggest that in long days, the developmental timing (leaf number) at which the reproductive transition occurs is influenced by day length and temperature through FT, while temperature influences the rate of leaf production and the time (in days) the transition occurs. Further, we demonstrated that FT is mainly produced in the first 10 leaves in the Columbia ecotype, and that FT accumulation alone cannot explain flowering in conditions in which flowering is delayed. Our simulations supported our hypotheses that: 1) temperature regulation of FT, accumulated with leaf growth, is a component of thermal time, and 2) incorporating mechanistic temperature regulation of FT can improve model predictions in fluctuating temperatures.

scholarly journals An explanatory model of temperature influence on flowering through whole-plant accumulation of FLOWERING LOCUS T in Arabidopsis thaliana

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Hannah A Kinmonth-Schultz ◽  
Melissa J S MacEwen ◽  
Daniel D Seaton ◽  
Andrew J Millar ◽  
Takato Imaizumi ◽  
...  
Keyword(s):  
Temperature Regulation ◽  
Leaf Growth ◽  
Day Length ◽  
Temperature Influence ◽  
Flowering Locus T ◽  
Leaf Production ◽  
Whole Plant ◽  
Improve Model ◽  
Flowering Locus ◽  
Flowering Regulator

Abstract We assessed mechanistic temperature influence on flowering by incorporating temperature-responsive flowering mechanisms across developmental age into an existing model. Temperature influences the leaf production rate as well as expression of FLOWERING LOCUS T (FT), a photoperiodic flowering regulator that is expressed in leaves. The Arabidopsis Framework Model incorporated temperature influence on leaf growth but ignored the consequences of leaf growth on and direct temperature influence of FT expression. We measured FT production in differently aged leaves and modified the model, adding mechanistic temperature influence on FT transcription, and causing whole-plant FT to accumulate with leaf growth. Our simulations suggest that in long days, the developmental stage (leaf number) at which the reproductive transition occurs is influenced by day length and temperature through FT, while temperature influences the rate of leaf production and the time (in days) the transition occurs. Further, we demonstrate that FT is mainly produced in the first 10 leaves in the Columbia (Col-0) accession, and that FT accumulation alone cannot explain flowering in conditions in which flowering is delayed. Our simulations supported our hypotheses that: (i) temperature regulation of FT, accumulated with leaf growth, is a component of thermal time, and (ii) incorporating mechanistic temperature regulation of FT can improve model predictions when temperatures change over time.

scholarly journals FLOWERING HTH1 is involved in CONSTANS-mediated flowering regulation in Arabidopsis

2019 ◽  
Vol 62 (1) ◽  
Author(s):  
Soon Ae Sim ◽  
Su Gyeong Woo ◽  
Dae Yeon Hwang ◽  
Jin-Hong Kim ◽  
Seung Sik Lee ◽  
...  
Keyword(s):  
Subcellular Location ◽  
Day Length ◽  
Interacting Protein ◽  
Photoperiodic Flowering ◽  
Family Protein ◽  
Flowering Regulation ◽  
Delayed Flowering ◽  
The Right ◽  
Two Hybrid ◽  
Repression Domain

Abstract Flowering at the right time is essential for maximum reproductive fitness. In Arabidopsis thaliana, the CONSTANS (CO) protein facilitates the transition from the vegetative phase to the reproductive phase under long-day conditions. The formation of heterodimeric complexes between CO and DNA binding domain-containing transcription factors is important for the induction of day length-dependent flowering. Here, we report a myb-like helix turn helix (HTH) transcriptional regulator family protein as a new modulator of floral transition, which we have named FLOWERING HTH1 (FHTH1). We isolated FHTH1 as a CO-interacting protein by a yeast two-hybrid screen using an Arabidopsis transcription factor library. Our analysis showed that FHTH1 presented in the nucleus and the FHTH1-CO complex was formed in the same subcellular location. We also observed the expression of a FHTH1:GUS construct in the leaf vasculature, where CO exists. Transgenic plants overexpressing FHTH1 fused with the plant-specific repression domain SRDX showed a delayed flowering phenotype in long days, resembling the phenotype of the co mutant. Our results suggest that FHTH1 may contribute to CO-mediated photoperiodic flowering regulation.

scholarly journals FLOWERING BHLH transcriptional activators control expression of the photoperiodic flowering regulator CONSTANS in Arabidopsis

2012 ◽  
Vol 109 (9) ◽  
pp. 3582-3587 ◽  
Author(s):  
S. Ito ◽  
Y. H. Song ◽  
A. R. Josephson-Day ◽  
R. J. Miller ◽  
G. Breton ◽  
...  
Keyword(s):  
Transcriptional Activators ◽  
Photoperiodic Flowering ◽  
Flowering Regulator

scholarly journals Phenology as a strategy for carbon optimality: a global model

2014 ◽  
Vol 11 (3) ◽  
pp. 763-778 ◽  
Author(s):  
S. Caldararu ◽  
D. W. Purves ◽  
P. I. Palmer
Keyword(s):  
Leaf Growth ◽  
Mechanistic Model ◽  
Leaf Age ◽  
Light Availability ◽  
Carbon Assimilation ◽  
Carbon Gain ◽  
Area Index ◽  
Growing Season Length ◽  
Tropical Areas ◽  
Gains And Losses

Abstract. Phenology is essential to our understanding of biogeochemical cycles and the climate system. We develop a global mechanistic model of leaf phenology based on the hypothesis that phenology is a strategy for optimal carbon gain at the canopy level so that trees adjust leaf gains and losses in response to environmental factors such as light, temperature and soil moisture, to achieve maximum carbon assimilation. We fit this model to five years of satellite observations of leaf area index (LAI) using a Bayesian fitting algorithm. We show that our model is able to reproduce phenological patterns for all vegetation types and use it to explore variations in growing season length and the climate factors that limit leaf growth for different biomes. Phenology in wet tropical areas is limited by leaf age physiological constraints while at higher latitude leaf seasonality is limited by low temperature and light availability. Leaf growth in grassland regions is limited by water availability but often in combination with other factors. This model will advance the current understanding of phenology for ecosystem carbon models and our ability to predict future phenological behaviour.

Physiological studies in birch

1984 ◽  
Vol 85 (1-2) ◽  
pp. 97-113
Author(s):  
K. A. Longman
Keyword(s):  
Shoot Growth ◽  
Seed Viability ◽  
Cambial Activity ◽  
Seasonal Cycles ◽  
Leaf Production ◽  
Factors Affecting ◽  
Whole Plant ◽  
Branching Patterns ◽  
Activity Onset ◽  
Unpublished Research

SynopsisAspects of whole-plant physiology of birch are reviewed, and previously unpublished research is presented. Seasonal cycles of shoot growth and bud dormancy are discussed, with environmental and hormonal factors affecting the rate and duration of shoot extension and leaf production. Also covered are variability in branching patterns, aspects of cambial activity, onset of the reproductive phase, factors affecting flowering and sex ratio, and seed viability and dormancy. Finally, the regenerative capacity of birch is described, and its future roles are mentioned.

Effects of nitrogen supply on xylem cytokinin delivery, transpiration and leaf expansion of pea genotypes differing in xylem-cytokinin concentration

2004 ◽  
Vol 31 (9) ◽  
pp. 903 ◽  
Author(s):  
Ian C. Dodd ◽  
Chuong Ngo ◽  
Colin G. N. Turnbull ◽  
Christine A. Beveridge
Keyword(s):  
Sap Flow ◽  
Leaf Growth ◽  
Xylem Sap ◽  
Leaf Expansion ◽  
Growth Responses ◽  
Flow Rates ◽  
Plant Transpiration ◽  
Discernible Effect ◽  
Whole Plant ◽  
N Treatment

The rms2 and rms4 pea (Pisum sativum L.) branching mutants have higher and lower xylem-cytokinin concentration, respectively, relative to wild type (WT) plants. These genotypes were grown at two levels of nitrogen (N) supply for 18–20 d to determine whether or not xylem-cytokinin concentration (X-CK) or delivery altered the transpiration and leaf growth responses to N deprivation. Xylem sap was collected by pressurising de-topped root systems. As sap-flow rate increased, X-CK declined in WT and rms2, but did not change in rms4. When grown at 5.0 mm N, X-CKs of rms2 and rms4 were 36% higher and 6-fold lower, respectively, than WT at sap-flow rates equivalent to whole-plant transpiration. Photoperiod cytokinin (CK) delivery rates (the product of transpiration and X-CK) decreased more than 6-fold in rms4. Growth of plants at 0.5 mm N had negligible (< 10%) effects on transpiration rates expressed on a leaf area basis in WT and rms4, but decreased transpiration rates of rms2. The low-N treatment decreased leaf expansion by 20–25% and expanding leaflet N concentration by 15%. These changes were similar in all genotypes. At sap-flow rates equivalent to whole-plant transpiration, the low N treatment decreased X-CK in rms2 but had no discernible effect in WT and rms4. Since the low N treatment decreased transpiration of all genotypes, photoperiod CK delivery rates also decreased in all genotypes. The similar leaf growth response of all genotypes to N deprivation despite differences in both absolute and relative X-CKs and deliveries suggests that shoot N status is more important in regulating leaf expansion than xylem-supplied cytokinins. The decreased X-CK and transpiration rate of rms2 following N deprivation suggests that changes in xylem-supplied CKs may modify water use.

Whole-Plant Responses to Salinity

1986 ◽  
Vol 13 (1) ◽  
pp. 143 ◽  
Author(s):  
R Munns ◽  
A Termaat
Keyword(s):  
Root Growth ◽  
Leaf Growth ◽  
Water Status ◽  
Leaf Expansion ◽  
Saline Soils ◽  
Plant Responses ◽  
Short Term ◽  
Whole Plant ◽  
Short Term Exposure

This paper discusses whole-plant responses to salinity in order to answer the question of what process limits growth of non-halophytes in saline soils. Leaf growth is more sensitive to salinity than root growth, so we focus on the process or processes that might limit leaf expansion. Effects of short-term exposure (days) are considered separately from long-term exposure (weeks to years). The answer in the short term is probably the water status of the root and we suggest that a message from the root is regulating leaf expansion. The answer to what limits growth in the long term may be the maximum salt concentration tolerated by the fully expanded leaves of the shoot; if the rate of leaf death approaches the rate of new leaf expansion, the photosynthetic area will eventually become too low to support continued growth.

scholarly journals Systematic Optimization of Whole Plant Carbon Nitrogen Interaction (WACNI) to Support Crop Design for Greater Yield

2018 ◽  
Author(s):  
Tian-Gen Chang ◽  
Xin-Guang Zhu
Keyword(s):  
Crop Yield ◽  
Mechanistic Model ◽  
Major Change ◽  
Plant Genome ◽  
Yield Potential ◽  
High Yield ◽  
Rice Grain ◽  
Molecular Processes ◽  
Whole Plant ◽  
Source Sink

AbstractOn the face of the rapid advances in genome editing technology and greatly expanded knowledge on plant genome and genes, there is a strong demand to develop an effective tool to guide designing crops for higher yields. Here we developed a highly mechanistic model of Whole plAnt Carbon Nitrogen Interaction (WACNI), which predicts crop yield based on major metabolic and biophysical processes in source, sink and transport tissues. WACNI accurately predicted the yield responses of so far reported source, sink and transport related genetic manipulations on rice grain yields. Systematic sensitivity analysis with WACNI was used to classify the source, sink and transport related molecular processes into four categories, i.e. universal yield enhancers, universal yield inhibitors, conditional yield enhancers and weak yield regulators. Simulations using WACNI further show that even without a major change in leaf photosynthetic properties, 54.6% to 73% grain yield increase can be potentially achieved by optimizing these molecular processes during the rice grain filling period while simply combining all the ‘superior’ molecular modules together cannot achieve the optimal yield level. A common macroscopic feature in all these designed high-yield lines is that they all show ‘a sustained and steady growth of grain sink’, which might be used as a generic selection criteria in high-yield rice breeding. Overall, WACNI can serve as a tool to facilitate plant source sink interaction research and guide future crops breeding by design.One sentence summaryA mechanistic model of source, sink flow model is developed and used to demonstrate that optimization of the whole plant carbon nitrogen metabolism can dramatically increase crop yield potential.

scholarly journals Photoperiodic Flowering Response of Essential Oil, Grain, and Fiber Hemp (Cannabis sativa L.) Cultivars

2021 ◽  
Vol 12 ◽  
Author(s):  
Mengzi Zhang ◽  
Steven L. Anderson ◽  
Zachary T. Brym ◽  
Brian J. Pearson
Keyword(s):  
Essential Oil ◽  
Environmental Conditions ◽  
Cannabis Sativa ◽  
Day Length ◽  
Tropical Region ◽  
Floral Initiation ◽  
Flowering Response ◽  
Photoperiodic Flowering ◽  
Critical Photoperiod ◽  
Different Sources

Cultivation of hemp (Cannabis sativa L.) in tropical and subtropical regions can be challenging if the flowering behavior of a given cultivar is unknown, poorly understood, or not accurately selected for the photoperiod. Identifying cultivars adapted to local environmental conditions is key to optimizing hemp vegetative and flowering performance. We investigated the effects of varying light cycles in regulating extension growth and flowering response of 15 essential oil and 12 fiber/grain hemp cultivars both indoors and outdoors. Plants were subjected to 11 photoperiods in the controlled rooms ranging from 12 to 18 h, and natural day length in the field. The critical photoperiod threshold was identified for seven essential oil cultivars and two fiber/grain cultivars. “Cherry Wine-CC,” “PUMA-3,” and “PUMA-4” had the shortest critical day length between 13 h 45 min and 14 h. The flowering of essential oil cultivars was generally delayed by 1–2 days when the photoperiod exceeded 13 h compared with 12 h, and flowering was further delayed by 7–8 days when the photoperiod exceeded 14 h. In fiber/grain cultivars, flowering was generally delayed by 1–3 days when the day length exceeded 14 h. Flowering for most essential oil cultivars was delayed by 5–13 days under a 14-h photoperiod compared with 13 h 45 min, suggesting a photoperiod difference as little as 15 min can significantly influence the floral initiation of some essential oil cultivars. Cultivars represented by the same name but acquired from different sources can perform differently under the same environmental conditions, suggesting genetic variation among cultivars with the same name. Average days to flower of fiber/grain cultivars was correlated with reported cultivar origin, with faster flowering occurring among northern cultivars when compared with southern cultivars. Plant height generally increased as the day length increased in essential oil cultivars but was not affected in fiber/grain cultivars. In addition, civil twilight of ~2 μmol·m−2·s−1 was discovered to be biologically effective in regulating hemp flowering. Collectively, we conclude that most of the essential oil cultivars and some southern fiber/grain cultivars tested express suitable photoperiods for tropical and sub-tropical region cultivation.

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