[Self-regulation of xylem pressure in barley roots under salt stress].

Xylem pressure in young barley roots, measured in vivo with a xylem pressure probe, showed constant, irregular fluctuations both under altered or unchanged environmental conditions. When mild salt stress was applied or when the stress was eliminated, xylem pressure in barley roots exhibited intense self-regulation or relaxation, leading to a consequence that the difference of xylem pressure before and after the salt stress was greatly narrowed and the barley plants could maintain a relatively stable xylem pressure. The process of regulation or relaxation of xylem pressure in barley roots lasted about one hour or more before a relatively stable state was achieved.