升压和降压过程玉米根系水分传输的比较  

Water transport in maize root system in the process of ascending and descending pressure

作　　者：刘晚苟[1] 山仑[1] 邓西平[1] 

机构地区：[1]中国科学院水利部水土保持研究所

出　　处：《水利学报》2002年第8期118-120,共3页Journal of Hydraulic Engineering

基　　金：国家重点基础研究发展规划项目 (G19990 1170 8)

摘　　要：利用压力室连续测定了升压过程和降压过程玉米根系的水流量和导水率。结果表明降压过程测得的根系水流量和导水率显著大于升压过程的 ,并且前者的起始压小于后者。根据根的复合运输模型 ,这种差异可能是由于升压和降压过程中质外体运输途径的细胞壁空间充水程度不同造成的。其生理意义在于使植物高蒸腾后仍维持高导水率 。The hydraulic conductance of maize root system was measured using a pressure chamber with consecutive ascending and descending pressure.The results showed that both water and hydraulic conductivity measured under descending pressure is remarkably greater than that under ascending pressure.But the former offset is smaller that of the later.The possible cause,based on composite transport model of the root,is that the water content in intercelluar spaces increased with increasing hydrostatic potential between root surface and xylem and hence increased apoplastic water flow and root hydraulic conductivity.This colud reflect an adaptive mechanism beneficial to water recovery for plant after a period of strong transpiration.

关 键 词：玉米根系 升降压 水流量 导水率 起始压 

分 类 号：S513[农业科学—作物学]