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STOMATAL RESISTANCE, TRANSPIRATION, AND RELATIVE WATER CONTENT AS INFLUENCED BY SOIL MOISTURE STRESS
Author(s) -
AlAni Tariq A.,
Bierhuizen J. F.
Publication year - 1971
Publication title -
acta botanica neerlandica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 0044-5983
DOI - 10.1111/j.1438-8677.1971.tb00715.x
Subject(s) - transpiration , water content , vapour pressure deficit , chemistry , soil water , horticulture , linear relationship , moisture , agronomy , botany , environmental science , soil science , biology , mathematics , photosynthesis , biochemistry , geotechnical engineering , statistics , organic chemistry , engineering
SUMMARY The effect of increasing soil moisture stress on stomatal resistance, transpiration, and relative water content of cucumber, beans and tomato has been investigated under controlled conditions. The results demonstrated that stomatal resistance can be used as a tool by which the soil‐water‐plant relationship can be predicted. Transpiration rates exhibited an initial rise as the soil moisture decreased, followed by a steady reduction. No significant changes in the relative water content of the leaves were observed until a severe soil moisture stress took place. For each species a linear relationship was obtained between the stomatal diffusive resistance (r sd ) and the ratio of the vapour pressure difference between leaf surface and bulk air (δ c ) over transpiration (E). The external resistances to water vapour (r a ) obtained from this relationship were 7.2, 4.4 and 2.8 sec cm −1 for cucumber, tomato and bean leaves, respectively. An essentially linear relationship was obtained between r sd and viscous air flow. The intercellular resistance (r i ) obtained from extrapolation of the curves, were 12.0, 8.7 and 6.6 sec cm −1 for cucumber, bean and tomato, respectively. The external resistance calculated from the sensible heat transfer is well below r a values in all species. The relatively high values of r a and r i have been discussed.