scholarly journals Environmental and physiological control of water flux through Pinuscontorta

1980 ◽  
Vol 10 (1) ◽  
pp. 82-91 ◽  
Author(s):  
Steven W. Running
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Potential Temperature ◽  
Water Flux ◽  
Soil Water Potential ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Physiological Control ◽  
Indirect Measure ◽  
Predawn Leaf Water Potential

This study reports measurements of leaf conductance, leaf water potential, temperature, humidity, and radiation collected on a stand of Pinuscontorta Dougl. ex Loud, lodgepole pine throughout a growing season at the Fraser Experimental Forest in central Colorado, U.S.A. The daily range of leaf conductances decreased 10-fold from June through August. A high correlation (R2 = 0.75) was found between predawn leaf water potential and morning maximum leaf conductance. Low atmospheric humidity significantly decreased midday leaf conductance. A comparison with humidity responses published for other conifers showed good agreement with this study. Seasonal change in total soil–plant resistance to water flux was nonlinearly correlated (R2 = 0.99) with change in predawn leaf water potential, an indirect measure of soil water potential.

Photosynthesis Response of Sunlit and Shade Pepper (Capsicum annuum) Leaves at Different Positions in the Canopy Under Two Water Regimes

1994 ◽  
Vol 21 (3) ◽  
pp. 377 ◽  
Author(s):  
A Alvino ◽  
M Centritto ◽  
FD Lorenzi
Keyword(s):  
Water Potential ◽  
Capsicum Annuum ◽  
Leaf Water Potential ◽  
Co2 Exchange ◽  
Leaf Water ◽  
Predawn Leaf Water Potential ◽  
Water Regimes ◽  
Water Potentials ◽  
Sun And Shade ◽  
Shade Leaves

Pepper (Capsicum annuum L.) plants were grown in 1 m2 lysimeters under two different water regimes in order to investigate differences in the spatial arrangements of the leaves and to relate this to daily assimilation rates of leaves of the canopy. The control regime (well-watered (W) treatment) was irrigated whenever the accumulated 'A' pan evaporation reached 4 cm, whereas the water-stressed (S) treatment was watered whenever the predawn leaf water potential fell below -1 MPa. During the growing cycle, equal numbers of sun and shade leaves were chosen from the apical, middle and basal parts of the canopy, corresponding to groups of leaves of increasing age. The CO2 exchange rate (CER) was measured at 0830, 1230 and 1530 hours on 8 days along the crop cycle, on leaves in their natural inclination and orientation. Leaf water potentials were measured on apical leaves before dawn and concurrently with gas exchange measurements. Control plants maintained predawn leaf water potential at -0.3 MPa, but S plants reached values lower than -1.2 MPa. Midday leaf water potentials were about twice as low in the S plants as in the controls. Water stress reduced LA1 during the period of crop growth, and dry matter production at harvest. Stressed apical leaves appeared to reduce stress by changing their inclination. They were paraheliotropic around midday and diaheliotropic at 0830 and 1530 hours. The CER values of the S treatment were significantly lower than those of the W treatment in apical and middle leaves, whereas the CER of basal leaves did not differ in either treatments. In the S treatment, reduction in the CER values of sunlit apical leaves was more evident in the afternoon than at midday or early in the morning, whereas basal leaves were less affected by water than basal stress leaves if sunlit, and negligibly in shaded conditions.

Predicting Predawn Leaf Water Potential up to Seven Days Using Machine Learning

2021 ◽  
pp. 39-50
Author(s):  
Ahmed A. Fares ◽  
Fabio Vasconcelos ◽  
Joao Mendes-Moreira ◽  
Carlos Ferreira
Keyword(s):  
Machine Learning ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Predawn Leaf Water Potential

The validity of predawn leaf water potential as an irrigation-timing indicator for field-grown wheat in northern Syria

2006 ◽  
Vol 82 (1-2) ◽  
pp. 223-236 ◽  
Author(s):  
Takahiro Sato ◽  
Osman S. Abdalla ◽  
Theib Y. Oweis ◽  
Tetsuo Sakuratani
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Water ◽  
Predawn Leaf Water Potential

Osmotic Adjustment in Expanding and Fully Expanded Leaves of Sunflower in Response to Water Deficits

1980 ◽  
Vol 7 (2) ◽  
pp. 181 ◽  
Author(s):  
MM Jones ◽  
NC Turner
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Osmotic Adjustment ◽  
Osmotic Potential ◽  
Leaf Water ◽  
Similar Degree ◽  
Tissue Water ◽  
Predawn Leaf Water Potential ◽  
Leaf Osmotic Potential ◽  
Osmotic Potentials

Sunflower plants were grown in large volumes of soil and slowly water-stressed by withholding water. The tissue water relationships of leaves at various stages of stress and of leaves of equivalent well watered controls were studied by the pressure chamber technique. Plants were stressed either when leaf 17 was expanding or when it was fully expanded. When expanding leaves reached a moderate level of stress (predawn leaf water potential of -0.9 MPa), the osmotic potentials at full turgor and zero turgor were lower than the control values by 0.1 MPa and 0.2 MPa, respectively. When fully expanded leaves were stressed to a similar degree (predawn leaf water potential of - 1.1 MPa), the osmotic potentials at full turgor and zero turgor were lower than the control values by 0.2 MPa and 0.3 MPa, respectively. The development of more severe stress in the fully expanded leaves was not accompanied by any further osmotic adjustment. However, when the expanding leaves reached a predawn leaf water potential of -2.3 MPa, the values of leaf osmotic potential at full turgor and zero turgor were lower than the values for the well watered plants by 0.4 MPa and 0.6 MPa, respectively. In expanding leaves prestressed to a predawn leaf water potential of -2.3 MPa, the osmotic potential at full turgor was significantly less than the control values for at least 7 days after rewatering. Stress had no effect on the bulk modulus of elasticity. It is concluded that both expanding and fully expanded sunflower leaves show osmotic adjustment.

Relation of Soybean Leaf Water Potential to Soil Water Potential 1

1974 ◽  
Vol 66 (6) ◽  
pp. 795-798 ◽  
Author(s):  
R. A. Brady ◽  
W. L. Powers ◽  
L. R. Stone ◽  
S. M. Goltz
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Soil Water Potential ◽  
Leaf Water ◽  
Soybean Leaf
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