Effects of severity and repetition of water stress on seed production of Macroptilium atropurpureum cv. Siratro

1987 ◽  
Vol 38 (3) ◽  
pp. 529 ◽  
Author(s):  
L Kowithayakorn ◽  
LR Humphreys
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Seed Production ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Severe Stress ◽  
Constant Height ◽  
Young Leaves ◽  
Macroptilium Atropurpureum ◽  
Leaf Differentiation

Macroptilium atropurpureum cv. Siratro was grown in large soil beds in a glasshouse with a water table at constant height below. Water stresses of dawn leaf water potential of - 1.0 MPa (medium stress) or of - 1.5 MPa (severe stress) were developed over 14 or 28 days, either singly or repeated after 42 days of rewatering. These stresses caused some death of terminal shoots and abscission of old leaves, but rapid rates of leaf differentiation restored leaf density to the levels of the control plants upon rewatering. A subsidiary experiment showed lower levels of leaf water potential in young leaves near the apex than in leaves subtending inflorescences.Persistent increases in the rate of floral bud appearance occurred upon rewatering, but the ratio of floral buds surviving to form an inflorescence with flowers was reduced both during and after the imposition of stress. A single cycle of medium stress increased seed yield 36% relative to the control plants, due to increased inflorescence and flower density. Repetition of water stress after 42 days was disadvantageous, and the effects of longer intervals between stress merit investigation. Severe stress of - 1.5 MPa was not beneficial to seed production.

Adaptation of Species of Centrosema to Water Stress

1983 ◽  
Vol 10 (2) ◽  
pp. 119 ◽  
Author(s):  
MM Ludlow ◽  
ACP Chu ◽  
RJ Clements ◽  
RG Kerslake
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Water Stress Tolerance ◽  
Strong Positive Relationship ◽  
Eastern Australia ◽  
North Eastern ◽  
Macroptilium Atropurpureum

The responses to water stress of five accessions representing four species of the legume Centrosema from contrasting moisture environments were compared under controlled conditions with those of Macroptilium atropurpureum cv. Siratro, a species which avoids dehydration. Species of Centrosema were able to tolerate leaf water potentials as low as -8 to -12 MPa, and all showed osmotic and stomatal adjustment. However, they differed in the tolerance of their leaves to water stress and in the leaf water potential at which stomata were effectively closed. There was a strong positive relationship between water stress tolerance of leaves and the leaf water potential for effective stomatal closure, among the Centrosema accessions and Siratro. The results are consistent with the natural ecological distribution of the species and their behaviour in different moisture environments in northern and north-eastern Australia.

Water stress and phenology in wheat

1977 ◽  
Vol 28 (2) ◽  
pp. 177 ◽  
Author(s):  
JF Angus ◽  
MW Moncur
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Mild Stress ◽  
Floral Initiation ◽  
Severe Stress ◽  
Development Models ◽  
Crop Development

Single wheat plants (cv. Gabo) were sown in tall pots and top-watered so that growth proceeded without stress until the time of floral initiation. Having reached this stage, plants encountered increasing stress as soil water was depleted. At intervals after the dawn leaf water potential, ψ1, had reached values of –5, –10, –15 bars etc., the stress was relieved with water sufficient for unstressed development until anthesis. The anthesis dates of plants which had encountered mild stress (ψ1 down to about ndash;15 bars) were ahead of the well-watered control, while those which had encountered more severe stress (ψ1 from about ndash;25 to ndash;40 bars) flowered after the controls. The results are discussed in relation to the possibilities of including the effects of stress in crop development models.

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.

Effects of water stress and soil type on photosynthesis, leaf water potential and yield of olive trees (Olea europaea L. cv. Chemlali Sfax)

2007 ◽  
Vol 47 (12) ◽  
pp. 1484 ◽  
Author(s):  
B. Ben Rouina ◽  
A. Trigui ◽  
R. d'Andria ◽  
M. Boukhris ◽  
M. Chaïeb
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Sandy Soil ◽  
Clay Soil ◽  
Sandy Loam ◽  
Leaf Water ◽  
Severe Drought ◽  
Relative Water ◽  
Olive Trees

In Tunisia, olives are grown under severe rain-fed, arid conditions. To determine the behaviour of olive trees (cv. Chemlali Sfax) during the severe drought affecting Tunisian arid areas in 2002, a range of physiological parameters were investigated in three adjacent orchards. Two olive orchards were rain-fed, one located on a sandy soil, and the other on a sandy-loam clay soil. A third orchard was also located on sandy soil, but received remedial irrigation (415 mm of water per year; ~40% of olive evapotranspiration). Predawn leaf water potential (Ψpd) did not fall below –1.52 MPa for irrigated olive trees. However, a large decrease in Ψpd was observed for rain-fed olive trees in the same period with Ψpd measured at about –3.2 MPa on sandy soil and –3.6 MPa on sandy-loam clay soil. At the same time, the minimal leaf water potential recorded at midday (Ψmin) decreased to –4.15 MPa and –4.71 MPa in the rain-fed trees for sandy and sandy-loam clay soil, respectively. For irrigated trees, the Ψmin was –1.95 MPa. These results were associated with relative water content, which varied from 80% for irrigated trees to 54 and 43.6%, respectively, for rain-fed trees and trees subjected to severe drought. In August, when the relative water content values were less than 50%, a progressive desiccation in the outer layer of canopy and death of terminal shoots were observed in trees, which grew on the sandy-loam clay soil. Furthermore, low soil water availability also affected (negatively) the net photosynthetic rate in rain-fed orchards (10.3 µmol/m2.s for irrigated trees v. 5.3 µmol/m2.s in rain-fed trees on sandy soil) and stomatal conductance (98.5 mmol/m2.s v. 69.3 mmol/m2.s). However, it improved water use efficiency (7.6 v. 4.7 µmol CO2/mmol H2O), which increased by more than 50% in both groups of rain-fed trees compared with the irrigated ones. We can conclude that olive trees respond to drought by showing significant changes in their physiological and biological mechanisms. These results also help our understanding of how olive trees cope with water stress in the field and how marginal soils can restrict growth and lower yields.

scholarly journals The importance of cuticular permeance in assessing plant water–use strategies

2020 ◽  
Vol 40 (4) ◽  
pp. 425-432
Author(s):  
Matthew Lanning ◽  
Lixin Wang ◽  
Kimberly A Novick
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Use ◽  
Leaf Water Potential ◽  
Stress Responses ◽  
Leaf Water ◽  
Plant Water ◽  
Stomatal Control ◽  
Plant Water Use ◽  
The Impact

Abstract Accurate understanding of plant responses to water stress is increasingly important for quantification of ecosystem carbon and water cycling under future climates. Plant water-use strategies can be characterized across a spectrum of water stress responses, from tight stomatal control (isohydric) to distinctly less stomatal control (anisohydric). A recent and popular classification method of plant water-use strategies utilizes the regression slope of predawn and midday leaf water potentials, σ, to reflect the coupling of soil water availability (predawn leaf water potential) and stomatal dynamics (daily decline in leaf water potential). This type of classification is important in predicting ecosystem drought response and resiliency. However, it fails to explain the relative stomatal responses to drought of Acer sacharrum and Quercus alba, improperly ranking them on the spectrum of isohydricity. We argue this inconsistency may be in part due to the cuticular conductance of different species. We used empirical and modeling evidence to show that plants with more permeable cuticles are more often classified as anisohydric; the σ values of those species were very well correlated with measured cuticular permeance. Furthermore, we found that midday leaf water potential in species with more permeable cuticles would continue to decrease as soils become drier, but not in those with less permeable cuticles. We devised a diagnostic parameter, Γ, to identify circumstances where the impact of cuticular conductance could cause species misclassification. The results suggest that cuticular conductance needs to be considered to better understand plant water-use strategies and to accurately predict forest responses to water stress under future climate scenarios.

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