[Effects of exogenous silicon on active oxygen scavenging systems in chloroplasts of cucumber (Cucumis sativus L.) seedlings under salt stress].

With K(2)SiO(4) (1.0 mmol/L) treatment, the effects of Si on the distribution of Na(+), K(+) to chloroplasts and antioxidant system of cucumber leaves under 50 mmol/L NaCl stress were studied. The results showed that there was a selective transport of K(+) into the chloroplasts so that Na(+) content of chloroplasts was lower under Si treatment (Table 1); H(2)O(2) and MDA contents in chloroplasts were significantly decreased (Fig.1), and the activities of SOD, APX, GR and DHAR were increased simultaneity (Fig.2), and AsA, GSH contents were also increased in chloroplasts of salt-stressed cucumber by additional Si treatment (Fig.3). It may be concluded that Si could decrease absorption of Na(+) and increase ability of active oxygen scavenging in chloroplasts, therefore the injury of chloroplast membrane under salinity stress in cucumber was alleviated.