scholarly journals Determination of Leaf Water Potential in Tomato Plants Using NIR Spectroscopy for Water Stress Management

2006 ◽  
Vol 44 (4) ◽  
pp. 279-284 ◽  
Author(s):  
Diding SUHANDY ◽  
Nafis KHURIYATI ◽  
Takahisa MATSUOKA
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Stress Management ◽  
Leaf Water Potential ◽  
Nir Spectroscopy ◽  
Leaf Water ◽  
Tomato Plants

scholarly journals EFEITO DO ARMAZENAMENTO DAS AMOSTRAS PARA DETERMINAÇÃO DO POTENCIAL DA ÁGUA NA FOLHA PELA CÂMARA DE PRESSÃO

Irriga ◽  
2007 ◽  
Vol 12 (3) ◽  
pp. 326-337 ◽  
Author(s):  
Ralini Ferreira de Melo ◽  
Yanê Borges Garcia Gruber ◽  
Rubens Duarte Coelho
Keyword(s):  
Water Stress ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Storage Time ◽  
Pressure Chamber ◽  
Leaf Water ◽  
De Se ◽  
Low Levels ◽  
Initial Measurement

EFEITO DO ARMAZENAMENTO DAS AMOSTRAS PARA DETERMINAÇÃO DO POTENCIAL DA ÁGUA NA FOLHA PELA CÂMARA DE PRESSÃO  Ralini Ferreira de Melo; Yanê Borges Garcia Gruber; Rubens Duarte CoelhoDepartamento de Engenharia Rural, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo, Piracicaba, SP, [email protected]  1 RESUMO O objetivo deste trabalho foi avaliar a influência do tempo de armazenamento das amostras de folhas de Citrus sp. na quantificação dos diferentes níveis de estresse hídrico, após as mesmas terem sido removidas das plantas, visando analisar a possibilidade de se fazer as medidas com a câmara de pressão (Scholander et al., 1964) na citricultura em condições de laboratório, e não imediatamente após a coleta das folhas. A amostragem constituiu-se em dez plantas para cada nível de estresse hídrico, com retirada de 5 folhas por planta e por coleta. Foram observadas as variações horárias dos valores nos tratamentos, com intervalos medidos de 0; 2; 4; 6; 8; 10; 12; 24; 48, 72 e 120 horas, sendo a primeira leitura às 6:00 horas do potencial total da água da folha. A determinação do potencial total da água nas plantas (yf) foi feita no pré-amanhecer e correlacionou-se o yf com o intervalo de tempo em que a medida foi feita após a coleta dessa amostra, resultando nas seguintes observações: a) com o passar do tempo de armazenamento das folhas cítricas ocorreu diminuição do potencial total da água, tornando-se mais negativo; b) com o aumento do nível de estresse hídrico, existiu uma menor interferência do tempo de leitura no potencial da água na folha para os menores níveis de estresse hídrico e c) o valor máximo de armazenamento recomendado é de seis horas. UNITERMOS: câmara de pressão, deficiência hídrica, irrigação  MELO, R. F. de; GRUBER, Y. B. G.; COELHO, R. D. EFFECT OF SAMPLE STORAGE FOR DETERMINATION OF LEAF WATER POTENTIAL USING A  PRESSURE CHAMBER  2 ABSTRACT This paper aimed to evaluate the storage time influence on the water potential of leaves (WPL) removed from citrus trees, and kept under no light and at low temperature conditions, prior to its determination using a Scholander´s chamber. Samples were taken from 10 trees of each water stress level (treatments), by removing 5 leaves at once. The variation of the water potential of leaves was observed for 2; 4; 6; 8; 10; 12; 24; 48, 72 and 120 hours after the initial measurement realized at 6:00 AM local time (predawn). The Scholander´s chamber determinations were correlated with the initial readings (predawn), resulting in the following observations: a) as storage time increased, there was a decrease of total leaf water potential, which became more negative;  b) with increase of water stress, there was a lower interference of storage time on leaf water potential; and c) under low levels of water stress the recommended maximum value for storage time is 6 hours. KEYWORDS: pressure chamber, water drought, irrigation

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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