scholarly journals Are crop and detailed physiological models equally "mechanistic" for predicting the genetic variability of whole plant behaviour? - the nexus between mechanisms and adaptive strategies

2020 ◽  
Author(s):  
F Tardieu ◽  
I S C Granato ◽  
E J Van Oosterom ◽  
B Parent ◽  
G L Hammer
Keyword(s):  
Genetic Variability ◽  
Growth And Yield ◽  
Specific Response ◽  
Response Curves ◽  
Evaporative Demand ◽  
Physiological Mechanisms ◽  
Physiological Models ◽  
Crop Models ◽  
Whole Plant ◽  
Developmental Traits

Abstract Tailoring genotypes for the variety of environmental scenarios associated with climate change requires modelling of the genetic variability of adaptation mechanisms to environmental cues. A large number of physiological mechanisms have been described and modelled, e.g. at transcript, metabolic or hormonal levels, but they remain to be assembled into whole-plant and canopy models. A 'bottom-up' approach combining physiological mechanisms leads to a near-infinite number of combinations and to an unmanageable number of parameters, so more parsimonious approaches are required. We propose that natural selection has constrained the large diversity of mechanisms into consistent strategies, in such a way that not all combinations of mechanisms are possible. These constraints, and resulting feedbacks, result in integrative 'metamechanisms', e.g. response curves of traits to environmental conditions, measurable via high throughput phenotyping, and resulting in robust and stable equations with heritable genotype-dependent parameters. Examples are provided for the responses of developmental traits to temperature, for the response of growth and yield to water deficit and evaporative demand, and for the response of tillering to light and temperature. In these examples, it was inoperative to combine upstream mechanisms into whole-plant mechanisms, whereas the evolutionary constraints on the combinations of physiological mechanisms renders possible the use of genotype-specific response curves at plant or canopy levels. These can be used for a new generation of crop models capable of simulating the behavior of thousands of genotypes. This has significant consequences for plant modelling and its use in genetics and breeding.

scholarly journals Salinity stress resistance in wheat

2021 ◽  
Vol 6 (1) ◽  
pp. 27
Author(s):  
Muniba Nazir
Keyword(s):  
Salinity Stress ◽  
Growth Yield ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Quality Trait ◽  
Physiological Mechanisms ◽  
Biochemical Processes ◽  
Whole Plant ◽  
Different Sources ◽  
Salinity Resistance

Wheat is used as staple food worldwide and it ranked third in cereals. Its productivity a the global level decreases by many stresses mainly by salinity stress which is associated with different physiological and biochemical processes of plants. To overcome these growth and yield reduction issues, salinity resistance in wheat can be achieved. The introduction of resistance to salinity-induced water stress and ion toxicity in wheat lead to more reliable results. Salt tolerance mechanisms at tissues and whole plant levels along with sequestration of toxic ions can improve overall growth, yield, and salinity resistance capability in wheat. Different sources and measurements of salinity play important role in the production of salinity tolerant wheat. This article mainly reviews different physiological mechanisms, genetics, omics, and quality trait loci approaches for the production of salinity tolerant wheat.

scholarly journals The contribution of PIP2-type aquaporins to photosynthetic response to increased vapour pressure deficit

2021 ◽  
Author(s):  
D Israel ◽  
S Khan ◽  
C R Warren ◽  
J J Zwiazek ◽  
T M Robson
Keyword(s):  
Vapour Pressure Deficit ◽  
Air Humidity ◽  
Wild Type ◽  
Knockout Mutant ◽  
Evaporative Demand ◽  
Co2 Transport ◽  
Whole Plant ◽  
Knockout Mutants ◽  
Leaf Level ◽  
Low Humidity

Abstract The roles of different plasma membrane aquaporins (PIPs) in leaf-level gas exchange of Arabidopsis thaliana were examined using knockout mutants. Since multiple Arabidopsis PIPs are implicated in CO2 transport across cell membranes, we focused on identifying the effects of the knockout mutations on photosynthesis, and whether they are mediated through the control of stomatal conductance of water vapour (gs), mesophyll conductance of CO2 (gm) or both. We grew Arabidopsis plants in low and high humidity environments and found that the contribution of PIPs to gs was larger under low air humidity when the evaporative demand was high, whereas any effect of lacking PIP function was minimal under higher humidity. The pip2;4 knockout mutant had 44% higher gs than the wild type plants under low humidity, which in turn resulted in an increased net photosynthetic rate (Anet). We also observed a 23% increase in whole-plant transpiration (E) for this knockout mutant. The lack of functional AtPIP2;5 did not affect gs or E, but resulted in homeostasis of gm despite changes of humidity, indicating a possible role in regulating CO2 membrane permeability. CO2 transport measurements in yeast expressing AtPIP2;5 confirmed that this aquaporin is indeed permeable to CO2.

scholarly journals Genetic variability and traits association in maize (Zea mays L.) varieties for growth and yield traits

Heliyon ◽  
2021 ◽  
pp. e07939
Author(s):  
Bigul Thapa Magar ◽  
Subash Acharya ◽  
Bibek Gyawali ◽  
Kiran Timilsena ◽  
Jharana Upadhayaya ◽  
...  
Keyword(s):  
Zea Mays ◽  
Genetic Variability ◽  
Zea Mays L ◽  
Growth And Yield ◽  
Yield Traits

scholarly journals Whole plant chamber to examine sensitivity of cereal gas exchange to changes in evaporative demand

Plant Methods ◽  
2018 ◽  
Vol 14 (1) ◽  
Author(s):  
Iván Jauregui ◽  
Shane A. Rothwell ◽  
Samuel H. Taylor ◽  
Martin A. J. Parry ◽  
Elizabete Carmo-Silva ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Evaporative Demand ◽  
Whole Plant

Negative Cross Resistance; a Possible Key to Atrazine Resistance Management: A Call for Whole Plant Data

1990 ◽  
Vol 45 (5) ◽  
pp. 470-473 ◽  
Author(s):  
Jonathan Gressel ◽  
Lee A. Segel
Keyword(s):  
Resistance Management ◽  
Cross Resistance ◽  
Response Curves ◽  
Maize Crop ◽  
Ps Ii ◽  
Atrazine Resistance ◽  
Whole Plant ◽  
Herbicide Mixtures ◽  
Plant Data ◽  
Plant Level

Many photosystem II inhibiting herbicides still inhibit this process in triazine-resistant plants; i.e. they have no cross resistance with atrazine. Five- to twenty-fold lower concentrations of phenolic type herbicidcs and 5-fold less of the active ingredient of pyridate and half as much ioxynil are required to inhibit thylakoid PS II in atrazine-resistant biotypes than in sensitive biotypes; i.e., they even show “negative cross resistance”. Negative cross resistance may be the major reason that atrazine resistance did not evolve where herbicide mixtures were used, when the mixed herbicide (usually a non-PS II inhibiting acetanilide) also controlled triazine-sensitivc weeds. Mathematical modeling in principle allows quantification of the very low field levels of herbicides possessing negative cross resistance that could be mixed with atrazine that would stop or delay the evolution of resistant populations without affecting the maize crop. There are few available actual dose response curves of atrazine-resistant vs. susceptible weeds at the whole plant level for herbicidcs exerting negative cross resistance. Thus, “real situation” modeling cannot be done. Data acquisition is called for so that the model can be extrapolated from the thylakoid to the field.

scholarly journals Quantifying herbicide dose–response and resistance in Echinochloa spp. by measuring root length in growth pouches

2015 ◽  
Vol 95 (6) ◽  
pp. 1181-1192 ◽  
Author(s):  
C. J. Zhang ◽  
S. H. Lim ◽  
J. W. Kim ◽  
J. S. Song ◽  
M. J. Yook ◽  
...  
Keyword(s):  
Dose Response ◽  
Root Length ◽  
Cost Savings ◽  
Acetolactate Synthase ◽  
Rapid Diagnosis ◽  
Response Curves ◽  
Whole Plant ◽  
Accurate Dose ◽  
Plant Assays ◽  
Als Inhibitors

Zhang, C. J., Lim, S. H., Kim, J. W., Song, J. S., Yook, M. J., Nah, G., Valverde, N. E. and Kim, D. S. 2015. Quantifying herbicide dose–response and resistance in Echinochloa spp. by measuring root length in growth pouches. Can. J. Plant Sci. 95: 1181–1192. The aim of the presented study was to develop a bioassay for rapid diagnosis of herbicide dose–response and resistance in Echinochloa. Pre-germinated seeds of Echinochloa spp. were incubated in growth pouches (18 cm×16.5 cm) containing herbicide solutions in a range of concentrations. Shoot and root lengths were measured after 6 d of incubation. Dose–responses estimated by measuring root lengths in the growth pouches were well-described by the log-logistic dose–response model and similar to those estimated by a whole-plant assay. Accurate dose–response curves were successfully generated for several herbicides with different modes of action, suggesting that the growth pouch method can be used for herbicide bioassays. The suitability of the growth pouch method for rapid diagnosis of acetyl coenzyme-A carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor resistance in Echinochloa spp. was also tested. For cyhalofop-butyl, resistant and susceptible biotypes were discriminated at 180–300 mg a.i. L−1 and 80–120 mg a.i. L−1 for barnyardgrass (E. crus-galli) and late watergrass (E. oryzicola), respectively. For penoxsulam, the discriminatory dosage was 350–500 mg a.i. L−1 for barnyardgrass and 650–1000 mg a.i. L−1 for late watergrass. The method was further used to identify late watergrass biotypes resistant and susceptible to two other ALS inhibitors, azimsulfuron and bispyribac-sodium. Our results show that the growth pouch method can be reliably used in herbicide dose–response studies and to diagnose herbicide resistance in Echinochloa spp., with significant time and cost savings compared with conventional whole-plant assays.

scholarly journals Corrigendum to “Genetic variability and traits association in maize (Zea mays L.) varieties for growth and yield traits”

Heliyon ◽  
2021 ◽  
pp. e08144
Author(s):  
Bigul Thapa Magar ◽  
Subash Acharya ◽  
Bibek Gyawali ◽  
Kiran Timilsena ◽  
Jharana Upadhayaya ◽  
...  
Keyword(s):  
Zea Mays ◽  
Genetic Variability ◽  
Zea Mays L ◽  
Growth And Yield ◽  
Yield Traits

scholarly journals Shading Affects Morphology, Dry-matter Partitioning, and Photosynthetic Response of Greenhouse-grown `Chardonnay' Grapevines

HortScience ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Justine E. Vanden Heuvel ◽  
John T.A. Proctor ◽  
K. Helen Fisher ◽  
J. Alan Sullivan
Keyword(s):  
Dry Matter ◽  
Dark Respiration ◽  
Light Response ◽  
Leaf Size ◽  
Dry Weight ◽  
Volume Density ◽  
Response Curves ◽  
Dry Matter Partitioning ◽  
Light Response Curves ◽  
Whole Plant

In order to gain an understanding of the capacity of severely shaded leaves to be productive in dense canopies, the effects of increased shading on morphology, dry-matter partitioning, and whole-plant net carbon exchange rate (NCER) were investigated on greenhouse-grown Vitis vinifera L. `Chardonnay' grapevines. Vines were subjected to whole-plant shading levels of 0%, 54%, 90%, and 99% of direct sun 3 weeks after potting. Data were collected 8 to 10 weeks after potting. Nonlinear regression was used to investigate the relationship of leaf morphological traits and organ dry weights to increased shading. Leaf size was maintained with increased shading to approximately the 90% shading level, while leaf fresh weight, volume, density, and thickness were immediately reduced with increased shading. Root dry weight was most affected by increased shading, and root to shoot ratio was reduced. When nonlinear regressions were produced for light response curves, light compensation point was reduced by approximately 49% by moderate shading, and 61% by severe shading. Shaded leaves approached the asymptote of the light response curve more quickly, and had reduced dark respiration rates, indicating that the morphological compensation responses by the vine allow shaded leaves to use available light more efficiently. However, the long-term ramifications of reduced root growth in the current year on vines with shaded leaves may be significant.

scholarly journals Water Use Effectiveness Is Enhanced Using Film Mulch Through Increasing Transpiration and Decreasing Evapotranspiration

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1153 ◽  
Author(s):  
Qianxi Shen ◽  
Risheng Ding ◽  
Taisheng Du ◽  
Ling Tong ◽  
Sien Li
Keyword(s):  
Water Use ◽  
Crop Production ◽  
Northwest China ◽  
Crop Growth ◽  
Soil Evaporation ◽  
Growth And Yield ◽  
Plastic Film ◽  
Evaporation Coefficient ◽  
Crop Models ◽  
Aquacrop Model

Water shortage is a main limitation of crop growth and yield in drought northwest China, which is an important area of seed maize growth. Plastic film mulch is widely adopted to reduce soil evaporation (E) and conserve water resources, which changes evapotranspiration (ET) and its components, E and transpiration (Tr) and crop growth. The AquaCrop model, one of widely used crop models powered by water, can well simulate crop ET components and growth. However, there are few studies that examine ET partitioning and growth with and without plastic film mulch. The calibrated AquaCrop model was used to partition ET and simulate growth of seed maize with and without plastic film mulch in a drought region of northwest China in 2014 and 2015. The AquaCrop model can well simulate canopy cover curve (CC), and the dynamic and accumulated courses of ET and ET components. Plastic film mulch could advance the growth stage of seed maize and reduce seasoned ET. The initial stage with plastic film mulch was 37–42 days, while it was 46–48 days for no-mulch. Plastic film mulch increased Tr by 14.16% and 14.48% and significantly decreased E by 57.25% and 34.28% in 2014 and 2015, respectively, resulting in the reduction of seasonal total ET. Plastic film mulch increased averaged mid-season crop coefficient for transpiration (Kc Tr) by 0.88% and decreased soil evaporation coefficient (Ke) by 62.50%. Collectively, the results suggest that, in comparison with no-mulch, plastic film mulch advanced crop growth, and decreased total ET and increased Tr related with crop production, i.e., improve water use effectiveness.

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