scholarly journals Water Stress Alter Leaf Hydric Status and Flower Bud Development in Apricot cv. “Royal”

2020 ◽  
pp. 10-19
Author(s):  
H. Ramírez ◽  
A. I. Melendres- Alvarez ◽  
A. Zermeño- González ◽  
D. Jasso- Cantú ◽  
J. A. Villarreal- Quintanilla
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Late Summer ◽  
Leaf Water ◽  
Full Bloom ◽  
Flower Buds ◽  
Flower Bud ◽  
Bud Development ◽  
Flower Bud Development

Aims: The apricot (Prunus armeniaca L.), is a drought-sensitive deciduous fruit. This concept arises from the fact that soil moisture stress can: Decrease the number and quality of flower buds differentiated; delay the time of flower differentiation and decrease the number of flower buds per shoot. The objectives of this investigation were to determine: The extent to which drought influences water status in the leaves; its effect on flower buds development and on bloom in apricot cv. “Royal”. Study Design: Trees were divided into 6 groups of six replicate each under a random block design. Results were analyzed using the statistical program 'RStudio' for Windows version 10 and data obtained subjected to a comparison of means with the Tukey (P≤0.05) test. Place and Duration of Study: The experiment was conducted at the Department of Horticulture in Universidad Autónoma Agraria Antonio Narro, Saltillo, Mexico, during 2018-2019. Methodology: Seven-year-old apricot trees growing in containers were subjected to a 4 to 5week period of water stress at different times during the growing season. Leaf water potential was periodically measured and flower bud development was followed from early differentiation up to full bloom. Results: Leaf water potential in water stressed trees was constantly low. Water stress early in the season induced a delay in bud development during late summer and fall. Water stress late in the season did not appreciably affect the rate of bud development. Full bloom was delayed when water stress was applied in late summer and fall. Water stress at flower bud initiation and differentiation, together with high temperatures, may have induced flowers with double pistils. Water stress from April through October did not induce flower drop. Conclusion: Soil water stress severely affect leaf water potential; delays flower bud development and may induce flowers with double pistils without flower drop.

scholarly journals Timing and Severity of Postharvest Water Stress Affect Following-year Productivity and Fruit Quality of Field-grown `Snow Queen' Nectarine

2005 ◽  
Vol 130 (6) ◽  
pp. 806-812 ◽  
Author(s):  
A. Naor ◽  
R. Stern ◽  
M. Peres ◽  
Y. Greenblat ◽  
Y. Gal ◽  
...  
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Water Status ◽  
Stem Water Potential ◽  
Flower Bud ◽  
Bud Development ◽  
Stem Water ◽  
Deep Suture ◽  
Flower Bud Development

The effects of the timing and severity of postharvest water stress on the productivity and fruit quality of field-grown nectarine [Prunus persica (L.) Batsch cv. Snow Queen] were studied for two consecutive years. Three levels of postharvest water status (midday stem water potentials of -1.2, -2.0, and -2.8 MPa) were examined. They were designated as High, Med, and Low, respectively. In the second year two additional treatments were examined in which Low and Med water status were interchanged on 1 Sept. 2002, and these treatments were designated as Low/Med and Med/Low. The percentages of double fruits and of those having a deep suture increased with decreasing postharvest midday stem water potential during the previous year, and most of these defects were stimulated by water deficits that occurred prior to 1 Sept. Postharvest water stress led to decreased crop yield in the subsequent year because there were fewer fruits per tree. Flower buds with double pistils were first noticed in mid-September, and by mid-November the ranking of double pistils in the various treatments were similar to the ranking of double fruits measured a month after bloom in the subsequent season. Postharvest water stress delayed flower bud development. The percentage of double fruits increased from 10% in 2002 to 40% in 2003 and the higher percentage in 2003 was associated with higher air temperatures during the reproductive bud development stage in 2002 than in 2001. Our data and others suggest that high temperatures create a potential for the occurrence of double fruits, but that the fulfillment of that potential is highly dependent on postharvest tree water status. The occurrence of double and deep suture fruits were highly correlated with midday stem water potential in August of the previous year, i.e., during the initial stages of flower bud development. The occurrence of double fruits was observed to increase sharply as the midday stem water potentials fell below -2.0 MPa, which suggests that a midday stem water potential of -2.0 MPa could serve as a threshold for postharvest irrigation scheduling.

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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