scholarly journals Leaf Water Potential, Stomatal Resistance, and Photosynthetic Response to Water Stress in Peach Seedlings

1982 ◽  
Vol 69 (5) ◽  
pp. 1051-1054 ◽  
Author(s):  
J. Mark Hand ◽  
Eric Young ◽  
Aurea C. Vasconcelos
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Photosynthetic Response ◽  
Response To Water

scholarly journals COMPARATIVE DROUGHT RESISTANCE AMONG SIX BIRCH (BETULA) SPECIES

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1143f-1143
Author(s):  
Thomas G. Ranney ◽  
R.E. Bir ◽  
W.A. Skroch
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Leaf Gas Exchange ◽  
Leaf Water ◽  
Mild Stress ◽  
Turgor Loss Point ◽  
Leaf Osmotic Potential ◽  
Response To Water

In order to evaluate and compare adaptability to dry sites, plant water relations and leaf gas exchange were compared in response to water stress among six birch species: monarch birch (Betula maximowicziana), river birch (B. nigra), paper birch (B. papyrifera), European birch (B. pendula), `Whitespire' Japanese birch (B. platyphylla var. japonica `Whitespire'), and gray birch (B. pendula). After 28 days without irrigation, Japanese birch maintained significantly higher stomatal conductance (gs) and net photosynthesis (Pn) than did any of the other species, despite having one of the lowest mid-day water potentials. Evaluation of tissue water relations, using pressure-volume methodology, showed no evidence of osmotic adjustment for any of these species in response to water stress. However, there was substantial variation among species in the water potential at the turgor loss point; varying from a high of -1.34 MPa for river birch to a low of -1.78 MPa for Japanese birch. Rates of Pn and gs under mild stress (mean predawn leaf water potential of -0.61 MPa) were negatively correlated with leaf osmotic potential at full turgor and the leaf water potential at the turgor loss point.

COMPARATIVE WATER STRESS STUDIES ON DROUGHT RESISTANT AND SUSCEPTIBLE CORN GROWN IN CHAMBER AND FIELD ENVIRONMENTS

1983 ◽  
Vol 63 (4) ◽  
pp. 775-787 ◽  
Author(s):  
A. L. SKRETKOWICZ ◽  
G. W. THURTELL
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Extended Period ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Stress Studies ◽  
Controlled Environments ◽  
Drought Resistant ◽  
Corn Plants

Drought resistant and drought susceptible corn plants were grown in both field and growth room environments in order to study differences in response to water stress attributable to their growth environments, including their prestress history.After 40–56 days of growth, field- and chamber-grown drought resistant and susceptible plants were placed in a growth cabinet for the drought stress experiments. There they underwent two stress cycles, during which time water was witheld. During the cycles, leaf water potential, transpiration, stomatal resistance and soil moisture content were monitored. The response differences due to water stress between the drought resistant and susceptible plants were first examined. Response differences due to their prestress growth environments were then considered.The responses of the field- and chamber-grown drought resistant plants to stress were found to be similar although there were differences in the absolute value of the responses measured. This was also true of the drought susceptible plants. The drought resistant plants were able to maintain their ability to extract water for a longer period of time than the susceptible plants. They maintained low stomatal resistance values for a large part of the drying cycle. The values of leaf water potential at which the stomatal resistances increased were lower than those of the drought susceptible plants. This enabled the drought resistant plants to extend their period of water utilization.During the drying cycles, the field-grown drought resistant and susceptible plants maintained low stomatal resistances and high transpiration rates for a longer period of time than their chamber counterparts. The values of leaf water potential at which stomatal resistance increased and transpiration decreased were lower than those of the chamber-grown plants, allowing the field-grown plants a slightly extended period of water utilization.The knowledge of prestress history of plants grown in different environments is shown to be of importance when comparative studies between field and controlled environments are undertaken. The similarity in response found between field- and chamber- grown plants is a useful factor as the chamber work with these particular cultivars is shown to be representative of field response at this location.Key words: Water stress, drought resistance, Zea mays L.

Water stress conditioning of corn (Zea mays) in the field and the greenhouse

1985 ◽  
Vol 63 (4) ◽  
pp. 704-710 ◽  
Author(s):  
L. M. Dwyer ◽  
D. W. Stewart
Keyword(s):  
Zea Mays ◽  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Leaf Water ◽  
Temperature Sensitive ◽  
Pressure Potential ◽  
Response To Water

Leaf water potential, osmotic potential, and leaf conductance were measured on corn (Zea mays L.) under water stress in the field and the greenhouse. Field-grown plants were subjected to several cycles of moderate water stress during vegetative growth, while greenhouse plants were well watered until just before the measurement period began following tasselling. In both the field and the greenhouse, leaf water potential declined at midday. Comparison of leaf water potential and osmotic potential measurements indicated that in both environments, the midday decline in leaf water potential was accompanied by a decline in osmotic potential. Since the decline in osmotic potential was greater than that accounted for by predicted volume changes resulting from normal daily dehydration, it was assumed to indicate osmotic adjustment. Despite these similarities, field-grown plants showed a greater response to water stress. Field plants underwent larger daily changes in leaf water potential and these were accompanied by larger changes in osmotic potential. As a result of this greater osmotic adjustment in the field, conductivity was higher at equivalent leaf water potentials and the critical leaf water potential was lower than in greenhouse-grown plants. In both environments, osmotic adjustment maintained leaf turgor (or pressure potential) in a narrow positive range. Although there was no direct relation between turgor potential and leaf conductivity, we hypothesize that the maintenance of a positive turgor potential during daylight hours is significant for growth since it may allow the moisture- and temperature-sensitive process of leaf expansion to proceed during the warmer daylight hours, even under moderate water stress.

scholarly journals Tolerance to Drought and Water Stress Resistance Mechanism of Castor Bean

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1580
Author(s):  
Eleni G. Papazoglou ◽  
Efthymia Alexopoulou ◽  
George K. Papadopoulos ◽  
Garifalia Economou-Antonaka
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Stress Resistance ◽  
Water Scarcity ◽  
Castor Bean ◽  
Resistance Mechanism ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Leaf Number

Castor bean (Ricinus communis L.) is a multipurpose crop; its oil has numerous applications worldwide and the last decade demonstrated a growing international demand. The aim of this work was to investigate the level of castor bean tolerance to drought and its possession of a water stress resistance mechanism by applying three different water regimes in a glasshouse pot experiment conducted for two years. The treatments applied were 70% (T70-control), 55% (T55) and 40% (T40) of the available soil moisture. The results showed that the growth parameters height, trunk diameter, and fresh and dry weights of leaves and stems were not affected by the moderate water scarcity (T55), while they were significantly decreased by T40. Significant decrease in leaf number was observed in both T55 (17%) and T40 (27%) plants, with a delay of 4 weeks in the lower treated plants. Leaf area was decreased by 54% and 20% in T55 and T40 respectively, indicating that its reduction was mainly due to a reduction of leaf size than of leaf number. The leaf water potential was increased negatively with increasing stress, showing a water loss and decrease of turgidity in cells. Stomatal resistance was significantly higher at the higher water scarcity and this response indicates a water stress resistance mechanism. This result was also confirmed by the regression analysis performed between stomatal resistance and leaf water potential. In conclusion, castor bean showed a tolerance ability under water stress conditions and its early physiological reaction allows its acclimatization to drought conditions.

INDICATORS OF WATER STRESS IN CORN (Zea mays L.)

1984 ◽  
Vol 64 (3) ◽  
pp. 537-546 ◽  
Author(s):  
L. M. DWYER ◽  
D. W. STEWART
Keyword(s):  
Zea Mays ◽  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Zea Mays L ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Predawn Leaf Water Potential ◽  
Diurnal Patterns ◽  
Potential Transpiration

Greenhouse experiments were conducted to monitor the response of corn (Zea mays L.) to water stress conditions during and following tasselling, and to compare several indicators of water stress. Daily measurements of soil water content and of evaporative demand were made. The degree of plant water stress was indicated by estimates of minimum daily stomatal resistance, comparison of estimated actual and potential transpiration rates, diurnal patterns of leaf water potential and predawn leaf water potentials taken on lower leaves. Analysis of the series of measurements necessary to estimate minimum daily stomatal resistance, actual to potential transpiration rate ratios, and diurnal patterns of leaf water potential identified periods of relative water stress. The simpler and less time-consuming measurement of predawn leaf water potential compared favorably with these other indicators of water stress. We therefore suggest that predawn leaf water potential is an appropriate diagnostic measurement of water stress with promise for irrigation scheduling, particularly for crops in which irrigation is important for a short but critical period.Key words: Leaf water potential, stomatal resistance, transpiration, vapor pressure deficit, soil water deficit

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