Temperature and water availability effects on radiation and water use efficiencies in alfalfa (Medicago sativa L.)

2005 ◽  
Vol 45 (4) ◽  
pp. 383 ◽  
Author(s):  
D. J. Collino ◽  
J. L. Dardanelli ◽  
M. J. De Luca ◽  
R. W. Racca

Alfalfa, the most important forage crop in Argentina, shows considerable variability in forage production caused by variations in inter-annual rainfall and intra-annual radiation and temperature regimes. Such variation may affect radiation use efficiency and water use efficiency. This paper seeks to study the effects of temperature and water availability on radiation use efficiency and water use efficiency. We conducted the experiment in Córdoba, Argentina, under irrigated and droughted conditions. Drought was imposed by mobile rainout shelters during 3 consecutive periods. We measured forage, intercepted photosynthetically active radiation and water use to calculate radiation use efficiency and water use efficiency between cuttings. Under irrigation, radiation use efficiency and water use efficiency normalised by daytime vapour pressure deficit, were not limited by mean temperature above 21.3 and 21.9°C, respectively. Below those critical values, both variables decreased consistently with temperature decrements. Under drought, radiation use efficiency tended to decrease and water use efficiency tended to increase. In addition, the relationship between relative dry matter and relative water use was not linear, as reported in previous studies for annual crops.

2013 ◽  
Vol 64 (3) ◽  
pp. 234 ◽  
Author(s):  
V. O. Sadras ◽  
G. J. Rebetzke

Here we propose that the perspective of phenotypic plasticity can enhance our understanding of the role of fertile tillers in accommodating environmental variation. We tested the hypothesis that the plasticity of yield correlates with the plasticity of ear number using free-tillering (–tin) and reduced-tillering (+tin) sister wheat lines in two genetic backgrounds, Lang and Silverstar. Crops were grown in 10 rainfed environments resulting from the combination of seasons, sites, nitrogen rates, and sowing dates. The combination of lines and environments generated a range from 157 to 357 ears m–2 at harvest, and a yield range from 1.9 to 4.2 t ha–1. Plasticity was quantified with two methods, slopes of reaction norms and variance ratios; both methods returned the same ranking of lines for both ear number and yield. The tin allele reduced the plasticity of both ear number and yield in Lang but not in Silverstar. The reduced plasticity associated with the tin allele in Lang had two components: a small reduction in ear number under low-yielding conditions, and a large reduction in the capacity to respond to higher yielding environments. Consistent with our working hypothesis, plasticity of yield and plasticity of ear number were correlated (R2 = 0.81, P = 0.01). Plasticity of ear number was associated with the plasticity of shoot biomass at harvest (R2 = 0.74, P = 0.006), and plasticity of biomass was associated with the plasticity of yield (R2 = 0.86, P = 0.0009). This suggests that the environmental responsiveness of yield was partially mediated by the environmental responsiveness of fertile tillers. We found positive correlations between plasticity of ear number and plasticity of several traits including biomass, radiation-use efficiency and water-use efficiency, and a negative correlation between plasticity of ear number and plasticity of seeds per ear. Ear number per se was unrelated to biomass, radiation-use efficiency, water-use efficiency, and seeds per ear. We conclude that a dual focus on traits per se and their plasticity is a fruitful approach to understand the phenotype, particularly when genotype × environment interaction is large.


Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 328 ◽  
Author(s):  
James R. Kiniry ◽  
Sumin Kim

Whole plant productivity is obviously the ultimate product of leaf photosynthesis and this has led to numerous efforts to relate the two. However, often with perennial grasses, plant productivity is more sink-limited than source-limited, causing the linkage between the photosynthetic rate and productivity to be weak or nonexistent. This has led to a different approach, characterizing plant productivity in terms of the efficiency of intercepted light use in producing biomass, also called radiation use efficiency. Likewise, the efficiency of the use of water to produce plant biomass, or water use efficiency, has been the object of much interest. The use of a simulation model to quantify biomass, using radiation use efficiency in parallel with a daily water balance simulation, allows for the effective calculation of water use efficiency. In this project, the process of determining radiation use efficiency with field data is described, as well as example values for highly productive perennial grasses useful for feedstock for bioenergy. In addition, values of water use efficiency for these grasses are reported and compared with other perennial grasses and common cultivated crops.


2021 ◽  
Vol 12 ◽  
Author(s):  
Huailin Zhou ◽  
Guangsheng Zhou ◽  
Li Zhou ◽  
Xiaomin Lv ◽  
Yuhe Ji ◽  
...  

The maximizing of water use efficiency (WUE) and radiation use efficiency (RUE) is vital to improving crop production in dryland farming systems. However, the fundamental question as to the association of WUE with RUE and its underlying mechanism under limited-water availability remains contentious. Here, a two-year field trial for maize designed with five progressive soil drying regimes applied at two different growth stages (three-leaf stage and seven-leaf stage) was conducted during the 2013–2014 growing seasons. Both environmental variables and maize growth traits at the leaf and canopy levels were measured during the soil drying process. The results showed that leaf WUE increased with irrigation reduction at the early stage, while it decreased with irrigation reduction at the later stage. Leaf RUE thoroughly decreased with irrigation reduction during the progressive soil drying process. Aboveground biomass (AGB), leaf area index (LAI), a fraction of absorbed photosynthetically active radiation (fAPAR), and light extinction coefficient (k) of the maize canopy were significantly decreased by water deficits regardless of the growth stages when soil drying applied. The interrelationships between WUE and RUE were linear across the leaf and canopy scales under different soil drying patterns. Specifically, a positive linear relationship between WUE and RUE are unexpectedly found when soil drying was applied at the three-leaf stage, while it turned out to be negative when soil drying was applied at the seven-leaf stage. Moreover, the interaction between canopy WUE and RUE was more regulated by fAPAR than LAI under soil drying. Our findings suggest that more attention must be paid to fAPAR in evaluating the effect of drought on crops and may bring new insights into the interrelationships of water and radiation use processes in dryland agricultural ecosystems.


2018 ◽  
Vol 36 (1) ◽  
pp. 7-13
Author(s):  
Melissa C. Smith ◽  
Richard N. Mack

Abstract Suitable plant water dynamics and the ability to withstand periods of low moisture input facilitate plant establishment in seasonally arid regions. Temperate bamboos are a major constituent of mixed evergreen and deciduous forests throughout temperate East Asia but play only an incidental role in North American forests and are altogether absent in the Pacific Northwest forest. Many bamboo species are classified as mesic or riparian, but none are considered drought tolerant. To assess their ability to withstand low water, we subjected five Asian temperate and one North American temperate bamboo species to three irrigation treatments: 100%, 50%, and 10% replacement of water lost through evapotranspiration. Plants were irrigated every four days over a 31-day period. Plant response to treatments was measured with stomatal conductance, leaf xylem water potentials, and intrinsic water use efficiency (iWUE). Pleioblastus distichus and Pseudosasa japonica showed significant reductions in conductance between high and low irrigation treatments. Sasa palmata had significantly lower stomatal conductance in all treatments. Pleioblastus chino displayed significantly higher iWUE in the mid irrigation treatment and Arunindaria gigantea displayed significantly lower iWUE than P. chino and S. palmata in the low irrigation treatment. The Asian bamboo species examined here tolerate low water availability and readily acclimate to different soil moisture conditions. Index words: Temperate bamboos, irrigation response, stomatal conductance, intrinsic water use efficiency. Species used in this study: Giant Cane [Arundinaria gigantea (Walt.) Muhl.]; Pleioblastus chino (Franchet & Savatier) Makino; Pleioblastus distichus (Mitford) Nakai; Pseudosasa japonica (Makino); Sasa palmata (Bean) Nakai.


2020 ◽  
Vol 462 ◽  
pp. 117999 ◽  
Author(s):  
Yansen Xu ◽  
Zhaozhong Feng ◽  
Bo Shang ◽  
Xiangyang Yuan ◽  
Lasse Tarvainen

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