חיפוש מתקדם
Plant, Cell and Environment
Li, Y., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel, Xinjiang Institute of Ecology and Geography, CAS, Urumqi, Xinjiang 830011, China
Fuchs, M., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel
Cohen, S., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel
Cohen, Y., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel
Wallach, R., Hebrew University of Jerusalem, Faculty of Agriculture, Department of Soil Science, Jerusalem, Israel
The effects of soil moisture distribution on water uptake of drip-irrigated corn were investigated by simultaneously monitoring the diurnal evolution of sap flow rate in stems, of leaf water potential, and of soil moisture, during intervals between successive irrigations. The results invalidate the steady-state resistive flow model for the continuum. High hydraulic capacitance of wet soil and low hydraulic conductivity of dry soil surrounding the roots damped significantly diurnal fluctuations of water flow from bulk soil to root surface. By contrast, sap flow responded directly to the large diurnal variation of leaf water potential. In wet soil, the relation between the diurnal courses of uptake rates and leaf water potential was linear. Water potential at the root surface remained nearly constant and uniformly distributed. The slope of the lines allowed calculating the resistance of the hydraulic path in the plant. Resistances increased in inverse relation with root length density. Soil desiccation induced a diurnal variation of water potential at the root surface, the minimum occurring in the late afternoon. The increase of root surface water potential with depth was directly linked to the soil desiccation profile. The development of a water potential gradient at the root surface implies the presence of a significant axial resistance in the root hydraulic path that explains why the desiccation of the soil upper layer induces an absolute increase of water uptake rates from the deeper wet layers.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Water uptake profile response of corn to soil moisture depletion
25
Li, Y., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel, Xinjiang Institute of Ecology and Geography, CAS, Urumqi, Xinjiang 830011, China
Fuchs, M., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel
Cohen, S., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel
Cohen, Y., Agricultural Research Organization, Institute of Soil, Water and Environmental Sciences, Volcani Center, P. O. Box 6, Bet Dagan 50250, Israel
Wallach, R., Hebrew University of Jerusalem, Faculty of Agriculture, Department of Soil Science, Jerusalem, Israel
Water uptake profile response of corn to soil moisture depletion
The effects of soil moisture distribution on water uptake of drip-irrigated corn were investigated by simultaneously monitoring the diurnal evolution of sap flow rate in stems, of leaf water potential, and of soil moisture, during intervals between successive irrigations. The results invalidate the steady-state resistive flow model for the continuum. High hydraulic capacitance of wet soil and low hydraulic conductivity of dry soil surrounding the roots damped significantly diurnal fluctuations of water flow from bulk soil to root surface. By contrast, sap flow responded directly to the large diurnal variation of leaf water potential. In wet soil, the relation between the diurnal courses of uptake rates and leaf water potential was linear. Water potential at the root surface remained nearly constant and uniformly distributed. The slope of the lines allowed calculating the resistance of the hydraulic path in the plant. Resistances increased in inverse relation with root length density. Soil desiccation induced a diurnal variation of water potential at the root surface, the minimum occurring in the late afternoon. The increase of root surface water potential with depth was directly linked to the soil desiccation profile. The development of a water potential gradient at the root surface implies the presence of a significant axial resistance in the root hydraulic path that explains why the desiccation of the soil upper layer induces an absolute increase of water uptake rates from the deeper wet layers.
Scientific Publication
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