tailieunhanh - Báo cáo lâm nghiệp: "Control of gas exchange: evidence for root-shoot communication on drying soil"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Control of gas exchange: evidence for root-shoot communication on drying soil. | 393s Ann. Sci. For. 1989 46 suppl. 393s-400s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Control of gas exchange evidence for root-shoot communication on drying soil T. Gollan1 . Davies2 u. Schurr1 and J. Zhang2 1 Universitat Bayreuth Lehrstuhl Pflanzenokologie POB 10 12 51 8580 Bayreuth . and 2 University of Lancaster Department of Biological Sciences Bailrigg Lancaster LA1 4YQ . Decrease in leaf conductance stomatai closure with drying soil is a common phenomenon and has been reported in myriads of publications stomatai closure with soil drying generally occurs in parallel with a deterioration of plant water status. With a decrease in relative water content leaf turgor and water potential in general decline. Since both leaf conductance and leaf water potential decrease more or less at the same time during a drying cycle the decrease in leaf conductance is often explained as a function of the decrease in leaf water potential. During the last few years increasing evidence has been accumulated that stomatai closure at drying soil is not only related to a deterioration in shoot water potential but also to changes in soil conditions. In this paper we summarize the experimental evidence that led US to hypothesize a communication between root and shoot on drying soil. Changes in plant performance with drying soil have been widely discussed during the last 50 years. Martin 1940 Veihmeyer and Hendrickson 1950 and Veihmeyer 1956 had previously concluded that the rate of transpiration was maintained until a critical soil water content was reached. With the introduction of thermodynamics in plant water relations and the development of more sophisticated measurement techniques leaf water potential became the controlling factor in most experimental hypotheses. It was an obvious thought because stomatai movements operate via changes in turgor of the guard cells and the surrounding epidermal cells . Raschke 1979 . Also in most experiments under .