摘要
采用压力室法测定了玉米和小麦苗期的根系导水率，井对升压法和降压法进行了比较。玉米苗期根系导水率测定结果表明，根系水流速率（L）随压力增加而增加，当静水压力△P〈0．8 MPa时，降压法测得的水流速率显著大于升压法，△P为0．8～1．2MPa时两者的测定结果基本相同，表明降压法测得的Jv与升压法的Jv之间的数值变化随△P压力改变有一个临界点。先升压再降压或降压后再升压过程比较发现，后一过程的Jv总是大于前一过程，说明压力诱导可能改变水分传导的方式。在0～2．0 MPa压力范围中，对玉米水培和小麦土培试验的降压法测定中，Jv都会出现一个平台，表明其导水过程存在着特定的传导机制。
Root system hydraulic conductance of seedling crops of maize and wheat were measured through pressure chamber, and the ascending and descending measurements were compared. The result of root system hydraulic conductance of seedling crops of maize showed： water flux （Jv） in the root system linearly increased with steady increases in imposed pressure. When imposed pressure （△ P） was below 0.8 MPa, Jv measured by notable higher than ascending measurements; when △ P was at 0.8 to 1.2 MPa, the measuring results were almost equal. This means that there was a critical point between Jv measured by descending and ascending measurements with △ P changing. Compared with the process of descending then ascending pressure and ascending then descending pressure, Jv in later process was always bigger than former process. This indicated that pressure inducement maybe changed the form of water conductance. In the pressure range of 0-2.0 MPa, Jv appeared a flat in measurement of descending pressure with maize water cultivation and wheat soil cultivation, which indicated that special conducing mechanism existed in the process of water conduced.
出处
《干旱地区农业研究》
CSCD
北大核心
2008年第3期115-118,共4页
Agricultural Research in the Arid Areas
基金
黄土高原土壤侵蚀与旱地农业国家重点实验室基金(10501-121)
西北农林科技大学2007年度学校科研专项资助基金(校基金
07ZR046)
关键词
根系导水率
升压法
降压法
玉米
小麦
root hydraulic conductance
ascending pressure method
descending pressure method
maize
wheat
