Recovery After Water Stress of Leaf Gas Exchange in Panicum maximum var. trichoglume

1980 ◽  
Vol 7 (3) ◽  
pp. 299 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng ◽  
CW Ford
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Water Potential ◽  
Net Photosynthetic Rate ◽  
Net Photosynthesis ◽  
Recovery Phase ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Rate Of Recovery ◽  
The Relationship

Net photosynthesis of the last fully expanded leaf of P. maximum var. trichoglume was able to recover from leaf water potentials as low as -92 bar. The degree of stress experienced during the single drying cycle did not influence the maximum net photosynthetic rate attained during recovery, but the time taken to reach the maximum increased with the degree of stress experienced. During the first 24 h, the rate of recovery of net photosynthesis was mainly determined by the rate at which the water status improved. Leaves which experienced water potentials less than c. -40 bar had a slower rate of recovery of water potential than less stressed leaves. This was partially offset by higher rates of net photosynthesis. Furthermore, the relationship between leaf water potential and net photosynthesis recorded during the drying cycle was different from those measured during recovery. Thus different relationships must be used in models simulating behaviour during water stress and subsequent recovery. Stomatal resistance exerted greater control than intracellular resistance over net photosynthesis in the recovery phase, irrespective of the water potential before rewatering or whether plants were preconditioned to stress. Although abscisic acid concentration was positively related to leaf water potential and stomatal resistance during the drying cycle, the relationship between abscisic acid concentration and stomatal resistance during recovery was poor or absent. Sucrose and amino-acid nitrogen accumulated during stress and decreased during recovery. However, the level of non- structural carbohydrates or nitrogen compounds in the recovery phase did not appear to influence net photosynthetic rate or its components. In fact, the reverse appeared to occur: the rate of photosynthesis and growth seemed to determine the levels of these compounds.

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 Interactions between leaf water potential, stomatal conductance and abscisic acid content of orange trees submitted to drought stress

2004 ◽  
Vol 16 (3) ◽  
pp. 155-161 ◽  
Author(s):  
Mara de Menezes de Assis Gomes ◽  
Ana Maria Magalhães Andrade Lagôa ◽  
Camilo Lázaro Medina ◽  
Eduardo Caruso Machado ◽  
Marcos Antônio Machado
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Acid Content ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Orange Trees ◽  
Abscisic Acid Content

Thirty-month-old 'Pêra' orange trees grafted on 'Rangpur' lemon trees grown in 100 L pots were submitted to water stress by the suspension of irrigation. CO2 assimilation (A), transpiration (E) and stomatal conductance (g s) values declined from the seventh day of stress, although the leaf water potential at 6:00 a.m. (psipd) and at 2:00 p.m. (psi2) began to decline from the fifth day of water deficiency. The CO2 intercellular concentration (Ci) of water-stressed plants increased from the seventh day, reaching a maximum concentration on the day of most severe stress. The carboxylation efficiency, as revealed by the ratio A/Ci was low on this day and did not show the same values of non-stressed plants even after ten days of rewatering. After five days of rewatering only psi pd and psi2 were similar to control plants while A, E and g s were still different. When psi2 decreases, there was a trend for increasing abscisic acid (ABA) concentration in the leaves. Similarly, stomatal conductance was found to decrease as a function of decreasing psi2. ABA accumulation and stomatal closure occurred when psi2 was lower than -1.0 MPa. Water stress in 'Pera´ orange trees increased abscisic acid content with consequent stomatal closure and decreased psi2 values.

scholarly journals Response of Leaf Water Potential, Stomatal Resistance, and Leaf Rolling to Water Stress

1980 ◽  
Vol 65 (3) ◽  
pp. 428-432 ◽  
Author(s):  
John C. O'Toole ◽  
Rolando T. Cruz
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Leaf Rolling

scholarly journals Growth, photosynthesis and leaf water potential in young plants of Copaifera langsdorffii Desf. (Caesalpiniaceae) under contrasting irradiances

2009 ◽  
Vol 21 (3) ◽  
pp. 197-208 ◽  
Author(s):  
Carlos Cesar Ronquim ◽  
Carlos Henrique B. A. Prado ◽  
João Paulo de Souza
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Photochemical Efficiency ◽  
Net Photosynthesis ◽  
Leaf Water ◽  
Total Biomass ◽  
Natural Conditions ◽  
Significant Difference ◽  
Copaifera Langsdorffii

Growth and leaf nutrient content were compared in young potted plants of Copaifera langsdorffii in sunny and shaded areas without water stress. Besides, carbon assimilation and leaf water relations were evaluated by net photosynthesis, potential photochemical efficiency and leaf water potential during daily courses in dry and rainy periods under natural conditions in both contrasting irradiances. Higher values of total biomass, height and leaf area occurred in sunny than in shaded area. On the other hand, all young plants survived in shade under natural water stress probably by reason of fast and intense biomass accumulation in favor of roots in early development. There was no significant difference about nutrient concentration in leaves between plants growing in sunny and shaded areas. Net photosynthesis in shade increased occasionally when bunches of direct light reached the leaves. Theses sunflecks took place more frequently and at high intensity in dry period but they were more effective for net photosynthesis in rainy period. The ability of young plants to persist under natural conditions in contrasting irradiance up to 1,230 days after sowing could explain the wide distribution of C. langsdorffii in Cerrado physiognomies and in different types of forest.

Effect of Water Deficit on Carbon Dioxide Exchange and Leaf Elongation Rate of Panicum maximum Var. trichoglume

1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng
Keyword(s):  
Carbon Dioxide ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Carbon Dioxide Exchange ◽  
Leaf Elongation ◽  
Water Deficits ◽  
Water Potentials

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.

Effect of Water Stress on Photosynthetic Parameters of Soybean (Glycine max) and Velvetleaf (Abutilon theophrasti)

Weed Science ◽  
1987 ◽  
Vol 35 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Philip H. Munger ◽  
James M. Chandler ◽  
J. Tom Cothren
Keyword(s):  
Glycine Max ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Net Photosynthetic Rate ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Abutilon Theophrasti ◽  
Leaf Water ◽  
Photosynthetic Parameters

Greenhouse experiments were conducted to elucidate the effects of water stress on photosynthetic parameters of soybean [Glycine max(L.) Merr. ‘Hutton′] and velvetleaf (Abutilon theophrastiMedik. # ABUTH). Stomatal conductance of both species responded curvilinearly to reductions in leaf water potential. At leaf water potentials less negative than −2.5 MPa, stomatal conductance, net photosynthetic rate, and transpiration rate were greater in velvetleaf than in soybean. Soybean photosynthetic rate was linearly related to stomatal conductance. Velvetleaf photosynthetic rate increased linearly with stomatal conductances up to 1.5 cm s–1; however, no increase in photosynthetic rate was observed at stomatal conductances greater than 1.5 cm s–1, indicating nonstomatal limitations to photosynthesis. As water stress intensified, stomatal conductance, photosynthetic rate, and transpiration of velvetleaf declined more rapidly than in soybean.

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.

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