scholarly journals Stomatal Resistance to Low Leaf Water Potential at Different Growth Stages Affects Plant Biomass in Glycine max L.

2007 ◽  
Vol 2 (3) ◽  
pp. 136-141 ◽  
Author(s):  
Adejare F. B. ◽  
Umebese C. E.
2020 ◽  
Vol 79 (1) ◽  
pp. 87-94
Author(s):  
Leila Romdhane ◽  
Nicola Dal Ferro ◽  
Amor Slama ◽  
Leila Radhouane

Rising temperatures and increasing water scarcity, which are already important issues, are expected to intensify in the near future due to global warming. Optimizing irrigation in agriculture is a challenge. Understanding the response of crop development stages to water deficit stress provides an opportunity for optimizing irrigation. Here we studied the response of two barley varieties (Rihane, Martin), to water deficit stress at three development stages (tillering, stem elongation, and heading) by measuring water status and grain yield components in a field experiment in Tunisia. The three stages were selected due to their importance in crop growth and grain development. Water deficit stress was initiated by withholding water for 21 days at the three stages with subsequent re-watering. Water deficit led to a progressive decrease in leaf water potential. In both varieties, heading was the stage most sensitive to water deficit. Leaf water potential measurements indicated that water deficit stress was more severe during heading, which to some extent may have influenced the comparison between growth stages. During heading, the number of ears per plant and weight of a thousand grains were reduced by more than 70% and 50%, respectively compared with stress at tillering. Comparison of yield components showed differences between the two barley varieties only when the water deficit was produced during the tillering stage.


The paper reports measurements of the water relations of a barley crop (cv. Proctor) and a winter wheat crop (cv. Maris Huntsman), grown on the same site at Sutton Bonington. Throughout the two growing seasons, days were chosen when hourly measurements could be made of leaf water potential, by means of a pressure chamber, and of stomatal resistance, by means of a diffusion porometer. Environmental factors, e.g. radiation, temperature, humidity, were recorded concurrently. Relationships between leaf water potential, stomatal resistance and environmental factors are explored and compared for the two cereals. In particular, as frequent measurements were made over two months, the influence of leaf age on responses to environmental factors can be examined. On selected days with bright sunshine and dry soil the response of both cereals to water stress is analysed with particular reference to the control of evaporation by stomatal closure


1974 ◽  
Vol 54 (1) ◽  
pp. 175-184 ◽  
Author(s):  
H. H. NEUMANN ◽  
G. W. THURTELL ◽  
K. R. STEVENSON

Peltier-cooled thermocouple dewpoint hygrometers were used to measure leaf water potentials at several transpiration rates on intact corn (Zea mays L.), soybean (Glycine max (L.) Merr.), and sunflower (Helianthus annus L.), grown in a controlled environment in silica sand rooting media frequently watered with nutrient solution. Hygrometers were left in position for the duration of measurements on each plant, but tests showed this to have little effect on measured potentials. Measured potentials were found to be linearly related to the transpiration rates (correlation coefficients greater than 0.98). Extrapolated values of leaf water potential at zero transpiration were within a few tenths bar of measured nutrient-solution potentials. These results indicated that plant resistances to water flow remained constant from near zero transpiration up to the maximum obtained average rates of 1.8–3.0 g dm−2 h−1. The magnitude of the resistance varied considerably from plant to plant even within a single cultivar of one species and definite conclusions as to interspecies differences in resistance were not made. Estimates of the relative resistance in the root, stalk, and the leaf that were made for a few plants were similar to previously published results.


1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng

The responses of carbon dioxide exchange and leaf elongation of potted P. maximum var. trichoglume plants to water deficits were investigated in controlled environments and outdoors during drying cycles down to -92 bars leaf water potential, The sensitivities of net photosynthesis and leaf elongation to water deficits were similar. The leaf water potentials at which net photosynthesis and elongation ceased (c. -12 bars), and stomatal resistance increased substantially (- 6 bars), were relatively unaffected by nitrogen supply, environmental conditions during growth, and whether plants had previously experienced stress. However, these factors influenced the rate of net photosynthesis, at high leaf water potentials by affecting stomatal resistance and at moderate water potentials by affecting both stomatal and intracellular resistances. Stomata1 resistance was more sensitive than intracellular resistance to water deficits. Dark respiration rate decreased with leaf water potential, and was higher in plants receiving additional nitrogen. At moderate leaf water potentials (-7 to -9 bars), net photosynthesis of this C4 grass exhibited light saturation and rates similar to C3 plants. We suggest that the difference in behaviour of controlled-environment-grown and field-grown plants to water deficits observed with some species is unlikely to be due to differences in the aerial environment, but may result from differences in the rate at which stress develops. The ecological significance and evolution of the C4 syndrome are discussed briefly.


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