The responses of leaf gas exchange and stomatal conductance to air humidity in shade-grown coffee, tea, and cacao plants as compared with sunflower
The responses of leaf gas exchange to leaf-air vapor pressure difference (VPD) in plants of coffee (Coffea arabica L.), tea (Camellia sinensis L.) and cacao (Theobroma cacao L.) that were grown under shade and in plants of sunflower (Helianthus annuus L.) grown in the open were compared under laboratory conditions. Stomatal conductance and apparent CO2 uptake rates of coffee, tea and cacao were reduced at large VPD to a greater extent than in sunflower. These reductions were associated with reductions in intercellular CO2 in the absence of significant changes in bulk leaf water potential. The transpiration rates of coffee, tea and cacao declined as VPD was increased above 1-1.5 kPa; whereas in sunflower transpiration increased, although nonlinearly, with rising VPD. Leaf water use efficiency was higher in sunflower than in coffee, tea and cacao due to the much greater CO2 uptake rate in the former. The strong and direct response of stomata to VPD in coffee, tea and cacao has significant implications for the performance of these tree crops under field conditions where they are normally cultivated
| Main Authors: | , , |
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| Format: | biblioteca |
| Published: |
1989
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| Subjects: | COFFEA ARABICA, THEOBROMA CACAO, CAMELLIA SINENSIS, HELIANTHUS ANNUUS, CULTIVO BAJO SOMBRA, RESISTENCIA ESTOMATICA, TRANSPIRACION, HUMEDAD DEL AIRE, PRESION OSMOTICA, |
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