Abscisic Acid Content and Osmotic Relations of Salt-Stressed Grapevine Leaves

1981 ◽  
Vol 8 (5) ◽  
pp. 443 ◽  
Author(s):  
WJS Downton ◽  
BR Loveys

Changes in abscisic acid, phaseic acid, stomatal resistance, water potential, osmotic potential, turgor potential, proline, reducing sugars and ion content (Na+, K+, Cl-) in leaves from grapevines (Vitis vinifera L.) subjected to 0, 25, 50 or 100 mM NaCl (osmotic potentials of 0, - 0.1, - 0.2 and - 0.4 MPa, respectively) were monitored over a 3-week period. Abscisic acid concentration increased within 6 h for the 50 and 100 mM NaCl-treated vines. Proline did not accumulate until the next day for the 100 mM NaCl-treated plants and continued to accumulate for the duration of the experiment. Phaseic acid showed kinetics consistent with its being derived from abscisic acid. Stomatal resistance to water vapour exchange increased in the salt-treated plants over the course of the experiment despite a decline in abscisic acid concentration after the initial upsurge. Reducing sugar concentration showed an early upsurge, its contribution to osmotic readjustment being at least equal to that of accumulated Na+, K+ and Cl- the day after stress began. Potassium was preferentially accumulated over sodium into leaves during the first 8 days of the experiment and the sum of these two cations generally balanced accumulating chloride. Except for an initial loss of turgor in vines given 100 mM NaCl, turgor potential was maintained within 0.1 MPa of control plants for all of the treatments throughout the experiment.

1974 ◽  
Vol 1 (3) ◽  
pp. 407 ◽  
Author(s):  
BR Loveys ◽  
PE Kriedemann

Both environmental factors and manipulative treatments (such as fruit excision or stem cincturing) were found to alter gaseous diffusion resistances in grape vine foliage. These responses have been analysed in terms of the hormonal physiology of Vitis vinifera L. leaf tissue. Environmental factors such as moisture stress or photoperiod alterations which contributed towards an increase in stomatal resistance (rs) were correlated with increased levels of endogenous abscisic acid (ABA) and phaseic acid (PA) in mature foliage. Conversely, treatments which elicited a decrease in rs were associated with lower levels of both ABA and PA. For example, rs had increased from 1.41 to 7.14 s cm-1 7 days after fruit removal and stem cincturing, while ABA and PA levels rose by 50 and 370 % respectively. This increase in endogenous ABA was not a consequence of decreased leaf water potential; moisture status was actually improved after treatment. It is proposed that changes in endogenous levels of ABA, and possibly PA, constitute a mechanism for regulating gas exchange in these perennial plants.


2013 ◽  
Vol 48 (9) ◽  
pp. 1210-1219 ◽  
Author(s):  
Muhammad Iqbal ◽  
Muhammad Ashraf

The objective of this work was to assess the regulatory effects of auxin-priming on gas exchange and hormonal homeostasis in spring wheat subjected to saline conditions. Seeds of MH-97 (salt-intolerant) and Inqlab-91 (salt-tolerant) cultivars were subjected to 11 priming treatments (three hormones x three concentrations + two controls) and evaluated under saline (15 dS m-1) and nonsaline (2.84 dS m-1) conditions. The priming treatments consisted of: 5.71, 8.56, and 11.42 × 10-4 mol L-1 indoleacetic acid; 4.92, 7.38, and 9.84 × 10-4 mol L-1 indolebutyric acid; 4.89, 7.34, and 9.79 × 10-4 mol L-1 tryptophan; and a control with hydroprimed seeds. A negative control with nonprimed seeds was also evaluated. All priming agents diminished the effects of salinity on endogenous abscisic acid concentration in the salt-intolerant cultivar. Grain yield was positively correlated with net CO2 assimilation rate and endogenous indoleacetic acid concentration, and it was negatively correlated with abscisic acid and free polyamine concentrations. In general, the priming treatment with tryptophan at 4.89 × 10-4 mol L-1 was the most effective in minimizing yield losses and reductions in net CO2 assimilation rate, under salt stress conditions. Hormonal homeostasis increases net CO2 assimilation rate and confers tolerance to salinity on spring wheat.


1992 ◽  
Vol 100 (2) ◽  
pp. 692-698 ◽  
Author(s):  
Aga Schulze ◽  
Philip J. Jensen ◽  
Mark Desrosiers ◽  
J. George Buta ◽  
Robert S. Bandurski

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

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.


1999 ◽  
Vol 50 (337) ◽  
pp. 1359-1364 ◽  
Author(s):  
D. J. Carrier ◽  
E. J. Kendall ◽  
C. A. Bock ◽  
J. E. Cunningham ◽  
D. I. Dunstan

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