Leaf Conductance and Leaf‐Water Potential Relationships for Two Soybean Cultivars Grown Under Controlled Irrigation 1

1979 ◽  
Vol 71 (2) ◽  
pp. 321-325 ◽  
Author(s):  
R. E. Carlson ◽  
N. N. Momen ◽  
O. Arjmand ◽  
R. H. Shaw
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Soybean Cultivars ◽  
Controlled Irrigation

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.

scholarly journals Effects of Low Relative Humidity and Illumination on Leaf Water Status of Cucumber Seedlings and Growth of Harvested Cuttings

HortScience ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 410-413 ◽  
Author(s):  
Toshio Shibuya ◽  
Ryoko Terakura ◽  
Yoshiaki Kitaya ◽  
Makoto Kiyota
Keyword(s):  
Relative Humidity ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Fresh Weight ◽  
Leaf Water Status ◽  
Air Temperatures ◽  
Total Fresh Weight

Application of a low-relative-humidity treatment (LHT) to seedlings can reduce water stress on cuttings harvested from the seedlings, after the cuttings are planted. Effects of illumination during LHT and LHT duration on leaf water potential and leaf conductance in cucumber (Cucumis sativus L.) seedlings used as the model plant material and on growth of harvested cuttings were investigated to determine optimal LHT conditions. The seedlings received LHT for 12 or 24 h in a lighted or dark growth chamber at air temperatures of 28 to 31 °C and relative humidity of 12% to 25%. Cuttings including a foliage leaf and two cotyledons were harvested by cutting the hypocotyl of the seedlings immediately after the treatment, and then the cuttings were planted in vermiculite medium. Four days after planting, the total fresh weight of the cuttings from seedlings that had received LHT in the lighted chamber was 2.2 times that of cuttings from seedlings that had not received LHT, whereas the total fresh weight of those that had received LHT in the dark increased by 1.3 to 1.8 times. Significant effects of illumination during LHT were also observed in the transpiration rate and growth of the cuttings, harvested following the treatment, after they were planted. By varying LHT duration, it was also found that leaf water potential and leaf conductance of the seedlings decreased as LHT duration increased up to 18 h. Thus, illumination during LHT increased the growth of cuttings taken following the treatment, and optimal treatment duration of around 18 h was estimated from the seedlings' leaf conductance and leaf water potential.

Yield and components of seed yield of indeterminate narrow-leafed lupin (Lupinus angustifolius L.) subjected to transient water deficit

1999 ◽  
Vol 50 (7) ◽  
pp. 1225 ◽  
Author(s):  
J. A. Palta ◽  
Z. Plaut
Keyword(s):  
Water Potential ◽  
Leaf Area ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Seed Yield ◽  
Dry Matter ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Water Deficits ◽  
Pod Number

The effect of transient water deficits on seed yield and components of seed yield of narrow-leafed lupin was measured in plants grown in a controlled environment under simulated field conditions. Lupins were grown in large columns of soil and transient water deficits were induced at pod set on the mainstem and first-order apical branches by withholding water for a 5-day period. Soil water content, leaf water potential, turgor pressure, and leaf conductance declined similarly during each period of transient water deficit. Differences in these parameters were apparent 2 days after water was withheld, and over the 5-day period, leaf water potential declined to −1.3 MPa and leaf conductance fell to 44% of the well-watered controls. Total dry matter per plant was reduced by the transient water deficit treatments. The reduction resulted from less accumulation of dry matter on the first, second, and third order apical branches. Leaf area on these branches was also reduced by abscission of the leaves after the water deficit was released. Seed yield per plant after each period of transient water deficit was reduced by 30–33%, relative to the well-watered controls. The reduction was largely due to a reduction in seed yield on the branches, mainly because they had fewer pods and seeds per pod. Seed dry weight and harvest index were not significantly affected by each period of transient water deficit. We conclude that differences in final seed yield between the well- watered controls and the transient water deficit treatments resulted from differences in pod number and seeds per pod. Low dry matter accumulation and reduction in leaf area on the first- and second-order apical branches under the transient water deficit were associated with the differences. Whereas the differences in pod number generated differences in the size of the reproductive sink, the differences in leaf area generated differences in the source capacity for assimilates for pod set and pod-filling.

Diurnal and Spatial Variation in Leaf Water Potential and Leaf Conductance of Irrigated Peach Trees

1983 ◽  
Vol 10 (3) ◽  
pp. 291 ◽  
Author(s):  
KA Olsson ◽  
FL Milthorpe
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Early Morning ◽  
Leaf Conductance ◽  
Leaf Water ◽  
High Productivity ◽  
Early Afternoon ◽  
Relative Water ◽  
Peach Trees ◽  
High Degree

Leaf water potential, conductance and relative water content were measured in three layers of the canopy of large peach trees during imgation cycles. In the top layer, leaf water potential decreased from early morning until the early afternoon reaching values ranging from about -1.8 MPa soon after irrigation to -2 5 MPa at the end of a drying cycle; leaf conductance (mean about 0.42 cm s-1) decreased slightly during this period but did not appear to be influenced by water potential at values higher than about - 1 .9 MPa. From early afternoon to late evening, leaf conductance continued to decrease and water potential increased. Similar cycles were noted in the middle and lower layers except that water potential was always higher and conductance lower. A high degree of exposure of leaves to insolation appeared to result in low potentials and high conductances. The adequacy of current imgation recommendations for high productivity is discussed.

Leaf water potential and leaf conductance during the growing season in almond trees under different irrigation regimes

1988 ◽  
Vol 30 (5) ◽  
pp. 327-332 ◽  
Author(s):  
M. C. Ruiz-Sýnchez ◽  
A. Torrecillas ◽  
F. Del Amor ◽  
A. Leon ◽  
J. M. Abrisqueta
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Growing Season ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Irrigation Regimes ◽  
Almond Trees

Agronomic and Physiological Responses of Soybean and Sorghum Crops to Water Deficits. III. Components of Leaf Water Potential, Leaf Conductance, 14co2 Photosynthesis and Adaptation to Water Deficits.

1978 ◽  
Vol 5 (2) ◽  
pp. 179 ◽  
Author(s):  
NC Turner ◽  
JE Begg ◽  
HM Rawson ◽  
SD English ◽  
AB Hearn
Keyword(s):  
Water Potential ◽  
Water Content ◽  
Soil Water ◽  
Leaf Water Potential ◽  
Relative Water Content ◽  
Leaf Conductance ◽  
Leaf Water ◽  
Starch Accumulation ◽  
Water Deficits ◽  
Relative Water

Concurrent measurements of leaf water potential, leaf osmotic potential, leaf relative water content, quantum flux density, leaf conductance, 14CO2 photosynthesis, soluble and insoluble sugars, starch and potassium concentrations were made diurnally on six occasions between flowering and maturity on upper leaves of irrigated and rainfed crops of soybean (cvv. Ruse and Bragg) and a rainfed crop of sorghum (cv. TX 610). With adequate soil water, sorghum had lower values of leaf conductance than did soybeans at high light and yet had higher rates of photosynthesis. Stage of plant development had no effect on either leaf conductance or photosynthesis of the youngest fully expanded leaves of both sorghum and soybean, but starch accumulation in the leaf over the day was less at grain-filling than at flowering in the soybean. Starch and sugar levels in the leaf had no apparent effect on photosynthesis. The daily minimum leaf water potential decreased in Ruse soybean from - 1.5 to -2.7 MPa as soil water was depleted. Late in the drying cycle, the daily minimum leaf water potential was higher in Bragg than in Ruse. In both cultivars, stomatal closure and decrease in 14CO2 photosynthesis commenced at leaf water potentials below - 1.5 MPa. Thus, the effect of water deficits on leaf conductance and photosynthesis occurred later in the drying cycle in Bragg than Ruse. As photosynthesis decreased with the depletion of soil water, starch accumulation in leaves of both cultivars of soybean decreased; changes in soluble and insoluble sugars and in potassium were small. The relationships among leaf water potential, osmotic potential, turgor potential, and leaf relative water content did not change with season or soil water depletion. Bragg and Ruse soybeans showed a similar response and both approached zero turgor at the same relative water content (82-83 %) and the same leaf water potential (- 1.5 to - 1.7 MPa). No evidence ofr osmotic adjustment was found in either soybean cultivar.

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