Drought Effects on Transpiration and Leaf Water Status of Cowpea in Controlled Environments

1980 ◽  
Vol 7 (2) ◽  
pp. 141 ◽  
Author(s):  
AE Hall ◽  
E Schulze
Keyword(s):  
Leaf Area ◽  
Water Status ◽  
Vapour Pressure Deficit ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Drought Treatment ◽  
Leaf Water Status ◽  
Unit Leaf ◽  
Drought Avoidance ◽  
Controlled Environments

The factors responsible for the extreme drought avoidance of cowpeas [Vigna unguiculata (L.) Walp.] previously observed in several field environments were investigated. Drought avoidance is defined as the extent to which high plant water potentials are maintained in the presence of environmental drought. Cowpeas were grown in controlled environments and subjected to either frequent irrigation or progressive drought. Plants in the drought treatment were grown for up to 2 months on 2-2.5 litres per plant of available water supplied 5 days after emergence. Transpiration of whole plants was determined by pot weighing, and leaf water status was determined with a pressure chamber. Well watered cowpeas avoided drought by two mechanisms: by avoiding water loss, because at constant air temperature transpiration increased only slightly with increases in vapour pressure deficit from 20 to 40 mbar; and due to an efficient water transport system which resulted in only small decreases in pressure chamber values with increases in transpiration at high rates of transpiration. Non-irrigated cowpeas avoided drought by maintaining low transpiration rates due to reduced leaf area and reduced transpiration per unit leaf area compared with irrigated plants.

Divergence in plant water-use strategies in semiarid woody species

2017 ◽  
Vol 44 (11) ◽  
pp. 1134 ◽  
Author(s):  
Rachael H. Nolan ◽  
Kendal A. Fairweather ◽  
Tonantzin Tarin ◽  
Nadia S. Santini ◽  
James Cleverly ◽  
...  
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Leaf Water Potential ◽  
Specific Leaf Area ◽  
Osmotic Potential ◽  
Water Status ◽  
Stomatal Closure ◽  
Woody Species ◽  
Leaf Water ◽  
Leaf Water Status

Partitioning of water resources amongst plant species within a single climate envelope is possible if the species differ in key hydraulic traits. We examined 11 bivariate trait relationships across nine woody species found in the Ti-Tree basin of central Australia. We found that species with limited access to soil moisture, evidenced by low pre-dawn leaf water potential, displayed anisohydric behaviour (e.g. large seasonal fluctuations in minimum leaf water potential), had greater sapwood density and lower osmotic potential at full turgor. Osmotic potential at full turgor was positively correlated with the leaf water potential at turgor loss, which was, in turn, positively correlated with the water potential at incipient stomatal closure. We also observed divergent behaviour in two species of Mulga, a complex of closely related Acacia species which range from tall shrubs to low trees and dominate large areas of arid and semiarid Australia. These Mulga species had much lower minimum leaf water potentials and lower specific leaf area compared with the other seven species. Finally, one species, Hakea macrocarpa A.Cunn ex.R.Br., had traits that may allow it to tolerate seasonal dryness (through possession of small specific leaf area and cavitation resistant xylem) despite exhibiting cellular water relations that were similar to groundwater-dependent species. We conclude that traits related to water transport and leaf water status differ across species that experience differences in soil water availability and that this enables a diversity of species to exist in this low rainfall environment.

Response of leaf water status, stomatal characteristics, photosynthesis and yield in black gram and green gram genotypes to soil water deficit

2015 ◽  
Vol 42 (10) ◽  
pp. 1010 ◽  
Author(s):  
Bhaswatee Baroowa ◽  
Nirmali Gogoi ◽  
Sreyashi Paul ◽  
Kushal Kumar Baruah
Keyword(s):  
Leaf Area ◽  
Seed Yield ◽  
Water Status ◽  
Crop Productivity ◽  
Leaf Water ◽  
Green Gram ◽  
Black Gram ◽  
Leaf Water Status ◽  
Stomatal Characteristics ◽  
Leaf Chlorophyll

Drought is one of the most important abiotic stresses constraining crop productivity worldwide. The objective of the present study was to investigate the differences in drought tolerance at leaf and stomatal level of black gram (genotypes: T9, KU 301, PU 19, USJD 113) and green gram (genotypes: Pratap, SG 21–5, SGC 16, TMB 37). Drought was applied for fifteen consecutive days at flowering stage (35 days after sowing). Mid-day leaf water potential (ΨL), leaf area, photosynthesis rate (PN), leaf chlorophyll, stomatal conductance (gs) and seed yield of drought- treated plants were calculated relative to those of well watered plants. Stomatal characteristics were observed in terms of stomatal frequency (SF) and stomatal aperture size (SA). Among the studied genotypes, T9 (black gram) and Pratap (green gram) proved their better tolerance capacity to drought by maintaining higher leaf area, ΨL, PN, leaf chlorophyll, gs and SA which contributed to better seed yield. Between the two crops, green gram appeared to be affected to a greater extent, as it experienced higher reduction in yield than black gram. A highly significant positive correlation (level 0.01) of seed yield was obtained with leaf area, ΨL, PN, leaf chlorophyll, gs and SA, whereas SF was found to be poorly correlated with seed yield.

scholarly journals Leaf water relations in epiphytic ferns are driven by drought avoidance rather than tolerance mechanisms

2021 ◽  
Author(s):  
Courtney Campany ◽  
Jarmila Pittermann ◽  
Alex Baer ◽  
Helen Holmlund ◽  
Eric Schuettpelz ◽  
...  
Keyword(s):  
Stomatal Density ◽  
Water Status ◽  
Costa Rican ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Trait Divergence ◽  
Drought Avoidance ◽  
Fern Species ◽  
Selection For

Opportunistic diversification has allowed ferns to radiate into epiphytic niches in angiosperm dominated landscapes. However, our understanding of how ecophysiological function allowed establishment in the canopy and the potential transitionary role of the hemi-epiphytic life form remain unclear. Here, we surveyed 39 fern species in Costa Rican tropical forests to explore epiphytic trait divergence in a phylogenetic context. We examined leaf responses to water deficits in terrestrial, hemi-epiphytic, and epiphytic ferns and related these findings to functional traits that regulate leaf water status. Epiphytic ferns had reduced xylem area (-63%), shorter stipe lengths (-56%), thicker laminae (+41%), and reduced stomatal density (-46%) compared to terrestrial ferns. Epiphytic ferns exhibited similar turgor loss points, higher osmotic potential at saturation, and lower tissue capacitance after turgor loss than terrestrial ferns. Overall, hemi-epiphytic ferns exhibited traits that share characteristics of both terrestrial and epiphytic species. Our findings clearly demonstrate the prevalence of water conservatism in both epiphytic and hemi-epiphytic ferns, via selection for anatomical and structural traits that avoid leaf water stress. Even with likely canalized physiological function, adaptations for drought avoidance have allowed epiphytic ferns to successfully endure the stresses of the canopy habitat.

scholarly journals Measuring Leaf-water Potential in Chickpea with a Pressure Chamber

1979 ◽  
Vol 15 (4) ◽  
pp. 377-383 ◽  
Author(s):  
M. V. K. Sivakumar ◽  
S. M. Virmani
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Water Status ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Leaf Water Status ◽  
Irrigated Crops ◽  
Different Depths ◽  
First Time

SUMMARYThe pressure-chamber technique has been used for the first time to measure leaf-water potentials in chickpea under field conditions. Available soil-water contents at different depths for irrigated and non-irrigated crops are presented along with the diurnal variation in leaf-water status, to show that pressure-chamber measurements correspond closely with available soil water. Leaf-water potential has also shown differences in leaf-water status among different cultivars. The rapidity and ease with which measurements can be made in the field make the technique suitable for quick measurements of leaf-water status for chickpea.

scholarly journals Grazing winter wheat relieves plant water stress and transiently enhances photosynthesis

2010 ◽  
Vol 37 (8) ◽  
pp. 726 ◽  
Author(s):  
Matthew T. Harrison ◽  
Walter M. Kelman ◽  
Andrew D. Moore ◽  
John R. Evans
Keyword(s):  
Water Stress ◽  
Leaf Area ◽  
Water Status ◽  
Leaf Water ◽  
Plant Water ◽  
Rubisco Activity ◽  
Leaf Water Status ◽  
Area Index ◽  
Plant Water Stress ◽  
The Impact

To model the impact of grazing on the growth of wheat (Triticum aestivum L.), we measured photosynthesis in the field. Grazing may affect photosynthesis as a consequence of changes to leaf water status, nitrogen content per unit leaf area (Na) or photosynthetic enzyme activity. While light-saturated CO2 assimilation rates (Asat) of field-grown wheat were unchanged during grazing, Asat transiently increased by 33–68% compared with ungrazed leaves over a 2- to 4-week period after grazing ended. Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively. Grazing did not alter Na. Using a photosynthesis model, we demonstrated that the increase in Asat after grazing required an increase in Rubisco activity of up to 53%, whereas the increase in Ci could only increase Asat by up to 13%. Increased Rubisco activity was associated with a partial alleviation of leaf water stress. We observed a 68% increase in leaf water potential of grazed plants that could be attributed to reduced leaf area index and canopy evaporative demand, as well as to increased rainfall infiltration into soil. The grazing of rain-fed grain cereals may be tailored to relieve plant water stress and enhance leaf photosynthesis.

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