scholarly journals Daily irrigation attenuates xylem abscisic acid concentration and increases leaf water potential ofPelargonium×hortorumcompared with infrequent irrigation

2016 ◽  
Vol 158 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Richard K.A. Boyle ◽  
Martin McAinsh ◽  
Ian C. Dodd
Keyword(s):  
Abscisic Acid ◽  
Water Potential ◽  
Acid Concentration ◽  
Leaf Water Potential ◽  
Leaf 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.

Applicability of abscisic acid and (or) proline accumulation as selection criteria for drought tolerance in Nicotiana tabacum

1994 ◽  
Vol 72 (10) ◽  
pp. 1535-1540 ◽  
Author(s):  
L. van Rensburg ◽  
G. H. J. Krüger
Keyword(s):  
Abscisic Acid ◽  
Drought Tolerance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Proline Accumulation ◽  
Leaf Water ◽  
Cell Wall Elasticity ◽  
Drought Tolerant ◽  
Acid Accumulation ◽  
Selection Parameters

The efficacy of various aspects of abscisic acid and proline accumulation as potential selection parameters for drought tolerance in tobacco was evaluated under controlled conditions. The results indicated that both abscisic acid (though being less pronounced) and proline accumulate rapidly after a distinct threshold leaf water potential value has been reached and that probably because of their higher cell wall elasticity (0.23 and 0.28 MPa for the drought-tolerant cultivars GS46 and Elsoma, respectively, compared with 0.39 and 0.31 MPa for the drought-sensitive cultivars TL33 and CDL28, respectively) these threshold leaf water potential values are reached sooner in drought-tolerant cultivars. However, abscisic acid accumulation precedes proline accumulation in both the drought-tolerant and drought-sensitive cultivars. Proline concentrations increased sharply at a leaf water potential of ca. −1.27 MPa in the drought-tolerant cultivars and at a leaf water potential of ca. −1.50 MPa in the drought-sensitive cultivars. At a leaf water potential of −0.77 MPa the abscisic acid concentrations of all four cultivars were already significantly higher than those of their respective controls and were greater in the drought-tolerant cultivars. The leaf water potential value at which abscisic acid and proline start accumulating rapidly and the accumulated proline end concentrations are recommended as selection parameters for drought tolerance in tobacco. Key words: abscisic acid accumulation, cell-wall elasticity, drought stress, Nicotiana tabacum L., proline accumulation, selection parameters.

Seasonal patterns of xylem sap pH, xylem abscisic acid concentration, leaf water potential and stomatal conductance of six evergreen and deciduous Australian savanna tree species

2002 ◽  
Vol 50 (2) ◽  
pp. 229 ◽  
Author(s):  
Dane S. Thomas ◽  
Derek Eamus
Keyword(s):  
Abscisic Acid ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Tree Species ◽  
Xylem Sap ◽  
Leaf Water ◽  
Deciduous Species ◽  
Evergreen Species ◽  
Water Potentials

Deciduous trees of Australia’s northern savannas typically have less-negative leaf water potentials than evergreen species and their stomata are more sensitive to soil drought than those of evergreen species. This paper presents the first investigation of the role of xylem sap pH and abscisic acid content in explaining stomatal behaviour of Australian trees in the field. We measured stomatal conductance, leaf-to-air vapour pressure difference (D) and leaf water potential, xylem abscisic acid (ABA) concentration and xylem sap pH of evergreen, semideciduous and fully deciduous tree species in the field over a 15-month period. Measurements were made during both the wet and the dry seasons. Stomata closed in response to increasing D in both evergreen and deciduous species and were equally sensitive to increasing D or declining leaf water potential. Xylem ABA concentration increased with declining leaf water potential in evergreen and semi-deciduous species, but not deciduous species. Similarly, there was an inverse correlation between stomatal conductance and xylem ABA concentration. Xylem sap pH increased as leaf water potential declined from wet to dry season for evergreen and semi-deciduous species but not for deciduous species. Deciduous species had less-negative water potentials and lower xylem ABA concentrations than evergreen species or semi-deciduous species. We conclude that changes in xylem sap pH and ABA content do occur seasonally in the wet–dry tropics of Australia and that these changes influence stomatal conductance, but only in evergreen and semi-deciduous species. Deciduous species do not appear to modulate either of these chemical signals.

Leaf Gas Exchange and Water Relations of Lupins and Wheat. III. Abscisic Acid and Drought-Induced Stomatal Closure

1989 ◽  
Vol 16 (5) ◽  
pp. 429 ◽  
Author(s):  
IE Henson ◽  
CR Jensen ◽  
NC Turner
Keyword(s):  
Abscisic Acid ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Stomatal Closure ◽  
Triticum Aestivum L ◽  
Leaf Water ◽  
Stomatal Response ◽  
Leaf Water Status

Changes in the content of endogenous abscisic acid (ABA) were followed in glasshouse experiments during stomatal closure induced by drought in leaves of lupin (Lupinus cosentinii Guss. cv. Eregulla) and wheat (Triticum aestivum L. cvv. Gamenya and Warigal), species which differ in stomatal sensitivity to changes in leaf water potential. Increases in bulk leaf ABA concentration were closely correlated with decreases in leaf conductance in both species. In lupin, substantial increases in ABA and decreases in conductance occurred over a very narrow range of leaf water potential. ABA concentrations in wheat leaves were highly negatively correlated with bulk leaf turgor, but there was no significant relationship between ABA and turgor in lupin. However, ABA accumulated progressively in the leaves of both species as soil water content decreased. Stomatal closure in lupin could be induced by supplying exogenous ABA to detached leaves via the transpiration stream at concentrations of 10-4 to 10-2 mol m-3 of (+)-ABA. Abaxial stomata closed more readily than those on the adaxial surface in response to both drought and applied ABA. Stomatal response to ABA was not affected by the presence of the cytokinin zeatin, and zeatin by itself had no effect on conductance. When treatments designed to reduce endogenous cytokinin concentrations were imposed (prolonged leaf detachment or prior drought), stomatal response to low concentrations of ABA was enhanced. However, such treatments did not significantly change the stomatal response to high ABA concentrations, nor affect the stomatal conductance of leaves supplied with water alone. It is concluded that drought-induced stomatal closure could be mediated by ABA in both wheat and lupin, despite the initially small change in leaf water status in the latter species.

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