Drought-Induced Changes in Xylem Sap pH, ABA and Stomatal Conductance

作     者：GUOXiu-lin LIUZi-hui Razzaq LIGuang-min 

作者机构：InstituteofGeneticsandPhysiologyHebeiAcademyofAgricultureandForestrySciencesShijiazhuang050051P.R.China Ph.D.StudentDoingResearchatHebeiAcademyofAgricultureandForestrySciencesShijiazhuang050051P.R.China 

出 版 物：《Agricultural Sciences in China》 (中国农业科学（英文版）)

年 卷 期：2004年第3卷第7期

页      面：496-501页

学科分类：09[农学] 0903[农学-农业资源与环境] 

基　　金：This work was financially supported by the Natural Science Foundation of Hebei Province,China(302466) the Developing Fund of Hebei Academy of Agriculture and Forestry Sciences,China(A03-1-02-14) 

主　　题：Drought Abscisic acid pH Xylem sap Signal Stomatal conductance 

摘      要：Upstream signals potentially regulating evaporation and stomatal conductance wereinvestigated using 6-8-leaf-old maize (Zea may L.) seedlings which were grown in agreenhouse. Pressure chamber was used to measure leaf water potential and to collectxylem sap. The pH of xylem sap in stems was higher than that in root, and the abscisicacid (ABA) concentration in stems was the highest in well-watered seedlings. The ABAconcentration and pH of xylem sap in roots, stems and leaves increased, and the ABAconcentration in leaves reached the maximum during drought stress. The treatment ofroots with exogenous ABA solution (100molL-1) increased xylem sap ABA concentration inall organs measured, and induced stomatal closure, but did not change ABA distributionamong organs of maize seedlings. The combined effects of external pH buffer on pH, ABAof xylem sap and stomatal behavior indicated that pH, as a root-source signal to leavesunder drought stress, regulated stomatal closure through accumulating ABA in leaves orguard cells.