scholarly journals THE EFFECT OF WATER STRESS ON RADIATION INTERCEPTION, RADIATION USE EFFICIENCY AND WATER USE EFFICIENCY OF MAIZE IN A TROPICAL CLIMATE

2017 ◽  
Author(s):  
Geneille E. GREAVES ◽  
Yu-Min WANG
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Tropical Climate ◽  
Radiation Use Efficiency ◽  
Radiation Interception ◽  
Effect Of Water ◽  
Use Efficiency ◽  
Radiation Use

Effect of water stress on growth, water use efficiency and gas exchange as related to osmotic adjustment of two halophytes Atriplex spp.

2013 ◽  
Vol 40 (5) ◽  
pp. 466 ◽  
Author(s):  
Oumelkheir Belkheiri ◽  
Maurizio Mulas
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Osmotic Adjustment ◽  
Late Summer ◽  
Field Capacity ◽  
Dry Weight ◽  
Co2 Assimilation ◽  
Effect Of Water ◽  
Use Efficiency

Atriplex halimus L. is known in the Mediterranean basin and along the coastal areas of Sardinia for its adaptability to salinity, although less information is available on the resistance of this species to water stress in absence of salinity. The effect of water stress on growth and water utilisation was investigated in two Atriplex species: A. halimus originating of south Sardinian island and the exotic species Atriplex nummularia Lindl., originating in Australia and widely used in land restoration of arid areas. Water stress was applied to young plants growing in 20 L pots with a sufficient water reserve to store a potentially sufficient water reserve to maintain substrate near to field capacity (30%) between irrigations. Watering was at 70% (control) or 40% (stress) of field capacity. In order to simulate the grazing by livestock, four plant biomass cuttings were conducted at times T0, T1, T2 and T3, corresponding to one cutting at the end of well watered phase (T0) before water stress induction, two cuttings after cycles of 5 weeks each during full summer (T1) and late summer (T2) and one cutting during autumn (T3). All plants remained alive until the end of treatment although growth was strongly reduced. Leaf dry weight (DW) and water use efficiency (WUE) were determined for all cuttings; relative water content (RWC), turgid weight : dry weight ratio (TW : DW), water potential (Ψw), osmotic potential (Ψs), CO2 assimilation, osmotic adjustment (OA), abscisic acid (ABA) and sugar accumulation were determined for the late summer cutting at T2. Water stress induced a decrease in DW, RWC, Ψw, Ψs, TW : DW and CO2 assimilation for both species, but an increase in WUE expressed in terms of dry matter production and a high accumulation of ABA and total sugars mainly for A. halimus. This suggests a more developed adaptive mechanism in this selection. Indeed, the clone was selected from the southern part of the island, where natural populations of saltbush are more exposed to abiotic stresses, mainly the water stress generated not by salinity. A. nummularia showed a greater OA and a positive net solute accumulation as than A. halimus, suggesting that water stress resistance in A. halimus is linked to a higher WUE rather than a greater osmotic adjustment.

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
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Water Availability ◽  
Vapour Pressure Deficit ◽  
Radiation Use Efficiency ◽  
Annual Rainfall ◽  
Forage Production ◽  
Temperature Regimes ◽  
Use Efficiency ◽  
Radiation Use

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.

Plasticity of wheat grain yield is associated with plasticity of ear number

2013 ◽  
Vol 64 (3) ◽  
pp. 234 ◽  
Author(s):  
V. O. Sadras ◽  
G. J. Rebetzke
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Radiation Use Efficiency ◽  
Shoot Biomass ◽  
Environment Interaction ◽  
Environmental Responsiveness ◽  
Use Efficiency ◽  
Per Se ◽  
Radiation Use ◽  
Ear Number

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.

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