Abscisic Acid in Leaves of Inbred Lines and F1 Hybrids of Maize Growing in the Field and Its Relationship to Diurnal and Seasonal Trends in Leaf Water Potential

1988 ◽  
Vol 61 (6) ◽  
pp. 669-678 ◽  
Author(s):  
S. Pekic ◽  
S. A. Quarrie
Keyword(s):  
Abscisic Acid ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Inbred Lines ◽  
Leaf Water ◽  
F1 Hybrids ◽  
Seasonal Trends

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 Trends in Carbon Assimilation, Stomatal Conductance, Pre-dawn Leaf Water Potential and Growth in Terminalia ferdinandiana, a Deciduous Tree of Northern Australian Savannas

1997 ◽  
Vol 45 (1) ◽  
pp. 53 ◽  
Author(s):  
L. D. Prior ◽  
D. Eamus ◽  
G. A. Duff
Keyword(s):  
Stomatal Conductance ◽  
Water Potential ◽  
Linear Relationship ◽  
Leaf Water Potential ◽  
Dry Season ◽  
Leaf Water ◽  
Deciduous Tree ◽  
Daily Maximum ◽  
Seasonal Trends ◽  
Terminalia Ferdinandiana

Seasonal trends in pre-dawn leaf water potential and morning and afternoon rates of light-saturated assimilation and stomatal conductance were studied in saplings of the deciduous tree Terminalia ferdinandiana Excell. Mean daily maximum assimilation rates ranged from 11 µmol m-2 s-1 in the wet season to 8 µmol m-2 s-1 during the transition from the wet to the dry season. Saplings were without leaves from June to October inclusive (dry season). There was a log–linear relationship between stomatal conductance and pre-dawn leaf water potential (r = 0.76, n = 325), and a weak linear relationship between daily maximum assimilation and pre-dawn leaf water potential (r = 0.39, n = 184). Assimilation rates were higher in the morning than in the afternoon in April and May, but were similar throughout the day from December to March. Seasonal trends in assimilation could be attributed primarily to stomatal closure, but diurnal differences could not. High leaf temperatures may have been responsible for observed lower assimilation rates in the afternoon in April and May. Assimilation and stomatal conductance decreased when leaf temperatures rose above 38˚C and/or the leaf-to-air vapour pressure difference exceeded 4–4.5 kPa. Pre-dawn leaf water potentials decreased more quickly, and stomatal conductance was more sensitive to this decrease, in T. ferdinandiana saplings than in saplings of Eucalyptus tetrodonta F.Muell. a co-occurring evergreen tree. Specific leaf area and assimilation per unit dry weight were higher in T. ferdinandiana than in E. tetrodonta which is consistent with other studies of costs and benefits of deciduousness.

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.

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