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United States Department of Agriculture

Agricultural Research Service

Title: Explanation and Modeling of Leaf Transpiration and Plant Water Stress Based on the Quantitative Leaf Anatomy

Authors
item Pachepsky, Ludmila
item Reddy, Vangimalla

Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 21, 2001
Publication Date: N/A

Technical Abstract: Transpiration is controlled by plant and affected by the environmental conditions. Water flow in plants is a passive process which occurs in response of physical forces. The general concept of stomatal operation mechanisms as affected by environmental conditions has been developed recently. For many species, stomatal transpiration is only one component in the total transpiration, and there are only empirical estimations of the non-stomatal transpiration that showed it varying in a range from 10 to 70% of the total value. Some experimental data on transpiration have not been explained so far. Quantitative leaf anatomy (mesophyll and intercellular spaces) has already demonstrated its significance in understanding the stomatal transpiration. On the basis of the analysis of other leaf components (epidermis, cuticles, cell walls), the hypothesis has been formulated about the regulation of leaf transpiration based on a new concept of the epidermis as a major source of the control. A new model can be developed which is capable to explain most of the experimental results that contradict with the current paradigm of leaf transpiration. It can also provide a quantitative formulation of the concept of plant water stress, drought tolerance, stress resistance. The current paradigm about the mechanisms of leaf transpiration appears to be insufficient, as the contemporary experimental studies show. Deeper understanding the mechanisms of transpiration is the core issue in the plant water stress physiology. The knowledge provided by the proposed study will also allow to design more adequately the development of drought resistant cultivars of the agricultural plants in both, traditional selection and genetic engineering.

Last Modified: 10/24/2014
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