Zinc and Salt Stress Influence on Proline Metabolism in Sesuvium Portulacastrum

摘要

This essay based on the stuff of Sesuvium portulacastrum , investigates the accumulating mechanism and the composing path of proline under three kinds of stress by ZnSO4, NaCl and ZnSO4+NaCl, the results showed that proline has great accumulation effect under the stress of ZnSO4, NaCl, ZnSO4+NaCl.Under the stress of 4% NaCl or 40 molL-1 ZnSO4 , the competence of proline accumulative effect decreases apparently, meanwhile, the activity of δ-OAT,P5CS related to the composing and metabolizing of proline shows the same tendency as proline accumulation does; but the proline accumulation in its body still remains in a comparative high level(290-330 μmol·g-1·FW-1). Therefore, S.portulacastrum is a kind of plant that can stand high concentration of Zn and salt. In the salinate soils of Zn deficiency, when S.portulacastrum was stressed under NaCl, the activity of P5CS was stimulated strikingly, whose proline composes and accumulates mainly by the glutamate pathway; while S.portulacastrum was stressed under Zn, the activity of δ-OAT is stimulated distinctly, whose proline composes and accumulates mainly by the ornithine pathway. In the place of low content of saline, it facilitates the composing and accumulating of proline when Zn was used increasingly to stimulate the activity of δ-OAT in the body of S.portulacastrum.