A Physiological Comparison of Leaves and Phyllodes in Acacia melanoxylon

1993 ◽  
Vol 41 (3) ◽  
pp. 293 ◽  
Author(s):  
T Brodribb ◽  
RS Hill
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Vapour Pressure Deficit ◽  
High Irradiance ◽  
Short Term ◽  
Evaporative Demand ◽  
Wide Range ◽  
Use Efficiency ◽  
Stomatal Sensitivity

Leaves and phyllodes of A. melanoxylon were compared in several aspects of their physiology. Changes in gas exchange and water use efficiency (WUE) under controlled conditions of vapour pressure deficit (vpd) and foliar water potential were examined. Water use efficiency in phyllodes remained constant under a wide range of evaporative demand due to high stomatal sensitivity to vpd. Leaf stomata were less sensitive to changes in vpd causing decreased WUE with increased vpd. Under water stress phyllodes survived longer and produced higher WUE than leaves. Maximum photosynthetic rates per unit foliar area were higher in phyllodes than leaves. Thus, phyllodes have a number of advantages over leaves under conditions of long and short term water stress and high irradiance. Leaves had a higher photosynthetic rate per unit of photosynthetic investment than phyllodes, suggesting that their function is to maximise growth during the seedling phase.

scholarly journals Reducing the Excessive Evaporative Demand Improved the Water-use Efficiency of Greenhouse Cucumber by Regulating the Trade-off between Irrigation Demand and Plant Productivity

HortScience ◽  
2018 ◽  
Vol 53 (12) ◽  
pp. 1784-1790 ◽  
Author(s):  
Dalong Zhang ◽  
Yuping Liu ◽  
Yang Li ◽  
Lijie Qin ◽  
Jun Li ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Flow ◽  
Water Use ◽  
Plant Productivity ◽  
Plant Water ◽  
Evaporative Demand ◽  
Plant Water Stress ◽  
Irrigation Demand ◽  
Use Efficiency

Although atmospheric evaporative demand mediates water flow and constrains water-use efficiency (WUE) to a large extent, the potential to reduce irrigation demand and improve water productivity by regulating the atmospheric water driving force is highly uncertain. To bridge this gap, water transport in combination with plant productivity was examined in cucumber (Cucumis sativus L.) grown at contrasting evaporative demand gradients. Reducing the excessive vapor pressure deficit (VPD) decreased the water flow rate, which reduced irrigation consumption significantly by 16.4%. Reducing excessive evaporative demand moderated plant water stress, as leaf dehydration, hydraulic limitation, and excessive negative water potential were prevented by maintaining water balance in the low-VPD treatment. The moderation of plant water stress by reducing evaporative demand sustained stomatal function for photosynthesis and plant growth, which increased substantially fruit yield and shoot biomass by 20.1% and 18.4%, respectively. From a physiological perspective, a reduction in irrigation demand and an improvement in plant productivity were achieved concomitantly by reducing the excessive VPD. Consequently, WUE based on the criteria of plant biomass and fruit yield was increased significantly by 43.1% and 40.5%, respectively.

Growth and yield response of barley and chickpea to water stress under three environments in southeast Queensland. III. Water use efficiency, transpiration efficiency and soil evaporation

1995 ◽  
Vol 46 (1) ◽  
pp. 49 ◽  
Author(s):  
s Thoma ◽  
S Fukai
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Vapour Pressure Deficit ◽  
Soil Evaporation ◽  
Growth And Yield ◽  
Yield Response ◽  
Transpiration Efficiency ◽  
Canopy Development ◽  
Use Efficiency

Two cultivars of barley and one cultivar of chickpea were grown in both well-watered and water stress conditions in three experiments. Water use efficiency (biomass produced per unit evapotranspiration) was lower in chickpea than in barley, and between two barley cultivars it was higher in early-maturing Corvette than in late-maturing Triumph. These differences in water use efficiency were mostly related to the differences in transpiration efficiency (biomass produced per unit transpiration). The latter appeared to reflect the differences in biomass production under well-watered conditions, as similar differences were found in light use efficiency (biomass produced per unit of photosynthetically active radiation intercepted) among the three crops. Transpiration efficiency was inversely related to vapour pressure deficit of the air. In three experiments soil evaporation accounted for about 55% and 10-30% of total water use for chickpea and barley respectively during observation periods, when rainfall was excluded from the plots. Slow canopy development of chickpea was a reason for such a high proportion of soil evaporation, and this contributed to its lower water use efficiency compared to barley. The amount of radiation transmitted to the soil surface appeared to be an important factor determining soil evaporation, even when soil water was not fully available and limiting soil evaporation.

scholarly journals Contrasting water-use strategies in two sympatric cool-temperate rainforest species, Nothofagus cunninghamii (Nothofagaceae) and Atherosperma moschatum (Atherospermataceae)

2008 ◽  
Vol 56 (2) ◽  
pp. 109 ◽  
Author(s):  
Katy E. Sommerville ◽  
Jennifer Read
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Temperate Rainforest ◽  
Water Deficits ◽  
Cool Temperate ◽  
Use Efficiency ◽  
Stomatal Sensitivity ◽  
Water Use Strategy

Nothofagus cunninghamii (Hook.) Oerst. and Atherosperma moschatum Labill. co-occur in cool-temperate rainforest across the wetter parts of Tasmania and Victoria, Australia, but A. moschatum extends to drier areas than N. cunninghamii. Possible reasons include differential tolerance of drought and fire or dispersal capacity. Here, we compare these species in their responses to water deficits. Differences in seedling survival, leaf tissue damage, shoot water relations, stomatal sensitivity, allocation of biomass and the long-term water-use efficiency of each species in response to water stress were investigated. N. cunninghamii showed traits typical of a high-water-use species, such as high stomatal conductance, a strategy that is not surprising in a rainforest species. However, it also displayed an exceptional ability to draw water from the soil and longer seedling roots, allowing replacement of water lost, at least in the short term. A. moschatum showed a more conservative water-use strategy, surviving greater internal dehydration with less damage, and displaying greater stomatal sensitivity to drought and long-term water-use efficiency in trees. The apparently superior long-term drought resistance of A. moschatum may in part explain its more common occurrence in drier regions than N. cunninghamii, at least in Tasmania, while the capacity of N. cunninghamii to survive short but severe periods of water stress correlates well with its higher position in the canopy and greater exposure to sunlight and desiccating winds. However, there is little evidence to suggest that the absence of N. cunninghamii from the rainforests of eastern Victoria is due to drought. We also suggest that the water-use strategy of N. cunninghamii may relate not just to surviving water deficits, but to maximising annual carbon gain in a temperate climate that is, on average, driest during the warmest time of the year.

Water Stress Effects on Growth, Yield and Water Use Efficiency of Hemarthria Compressa

2012 ◽  
Vol 212-213 ◽  
pp. 578-585
Author(s):  
Zhong Wen Yang ◽  
Jun Ying Jin ◽  
Xin Yi Xu
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Control Period ◽  
Growth Yield ◽  
Control Treatment ◽  
Sensitive Period ◽  
Total Biomass ◽  
Use Efficiency ◽  
Hemarthria Compressa

Water stress is an important approach to use water resources efficiently and remit the agricultural water shortage. Hemarthria compressa is one of perennial grasses, a pasture of high quality, which has abundant species resources in China. To explore the response of the growth, yield and water use efficiency(WUE) of Hemarthria compressa under water stress, this study, adapting pot experiment, imposed three water stress degree (LD, MD and SD) treatments and a control treatment on Hemarthria compressa. The data of growth indicators during control period, yield and total water consumption were obtained. The results show a noticeable inhibitory action of water stress on the growth of Hemarthria compressa. Along with the intensifying of water stress, plant height increment, leaf area, total biomass, dry matter of each organ and yield decreased, and the root-shoot ratio increased firstly and inclined to slump finally. Plants under the middle water stress treatment achieved the greatest WUE of 38.25 kg/m3. The first 10d in the water control period was the most sensitive period of the pasture responding to water stress.

scholarly journals High-throughput phenotyping reveals a link between transpiration efficiency and transpiration restriction under high evaporative demand and new loci controlling water use-related traits in African rice, Oryza glaberrima Steud.

2021 ◽  
Author(s):  
Pablo Affortit ◽  
Branly Effa Effa ◽  
Mame Sokhatil Ndoye ◽  
Daniel Moukouanga ◽  
Nathalie Luchaire ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Association Studies ◽  
Crop Improvement ◽  
Oryza Glaberrima ◽  
Genome Wide Association Studies ◽  
Transpiration Efficiency ◽  
Evaporative Demand ◽  
African Rice ◽  
Use Efficiency

Because water availability is the most important environmental factor limiting crop production, improving water use efficiency, the amount of carbon fixed per water used, is a major target for crop improvement. In rice, the genetic bases of transpiration efficiency, the derivation of water use efficiency at the whole-plant scale, and its putative component trait transpiration restriction under high evaporative demand, remain unknown. These traits were measured in a panel of 147 African rice Oryza glaberrima genotypes, known as potential sources of tolerance genes to biotic and abiotic stresses. Our results reveal that higher transpiration efficiency is associated with transpiration restriction in African rice. Detailed measurements in a subset of highly differentiated genotypes confirmed these associations and suggested that the root to shoot ratio played an important role in transpiration restriction. Genome wide association studies identified marker-trait associations for transpiration response to evaporative demand, transpiration efficiency and its residuals, that links to genes involved in water transport and cell wall patterning. Our data suggest that root shoot partitioning is an important component of transpiration restriction that has a positive effect on transpiration efficiency in African rice. Both traits are heritable and define targets for breeding rice with improved water use strategies.

scholarly journals Gas exchanges and water use efficiency in the selection of tomato genotypes tolerant to water stress

2017 ◽  
Vol 16 (2) ◽  
Author(s):  
M.E.A. Borba ◽  
G.M. Maciel ◽  
E.F. Fraga Júnior ◽  
C.S. Machado Júnior ◽  
G.R. Marquez ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Gas Exchanges ◽  
Use Efficiency ◽  
Tomato Genotypes ◽  
Selection Of

Response of greenhouse-grown bell pepper (Capsicum annuum L.) to variable irrigation

2014 ◽  
Vol 94 (2) ◽  
pp. 303-310 ◽  
Author(s):  
Olanike Aladenola ◽  
Chandra Madramootoo
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Capsicum Annuum ◽  
Water Use ◽  
Irrigation Water ◽  
Bell Pepper ◽  
Marketable Yield ◽  
Capsicum Annuum L ◽  
Use Efficiency

Aladenola, O. and Madramootoo, C. 2014. Response of greenhouse-grown bell pepper (Capsicum annuum L.) to variable irrigation. Can. J. Plant Sci. 94: 303–310. In order to optimize water use in bell pepper production information about the appropriate irrigation water applications and agronomic and physiological response to mild and severe water stress is necessary. Different water applications were tested on yield, quality and water stress threshold of greenhouse-grown bell pepper (Capsicum annuum L.) cultivar Red Knight in 2011 and 2012 on the Macdonald Campus of McGill University, Ste Anne De Bellevue, QC. The study was carried out on a soil substrate in the greenhouse. Irrigation was scheduled with four treatments:120% (T1), 100% (T2), 80% (T3), and 40% (T4) replenishment of crop evapotranspiration in a completely randomized design. The highest marketable yield, water use efficiency and irrigation water use efficiency were obtained with T1 in both years. T1 received 20% more water than T2 to produce 23% more marketable yield than T2. Fruit total soluble solids content was highest in T4, and smallest in T1. The mean crop water stress index (CWSI) of the irrigation treatments ranged between 0.08 and 1.18. Leaf stomatal conductance of bell pepper was 75 to 80% lower in T4 than in T1. Regression obtained between stomatal conductance and CWSI resulted in a polynomial curve with coefficients of determination of 0.88 and 0.97 in 2011 and 2012, respectively. The result from this study indicate that the yield derived justifies the use of an extra quantity of water. Information from this study will help water regulators to make appropriate decision about water to be allocated for greenhouse production of bell pepper.

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