[Effects of Ni2+ on physiological characteristics and submicroscopic structure of Salvinia natans leaves].

Influence of 0, 5, 10, 15, 20 mg/L Ni2+ on growth, mineral nutrition, chlorophyll, carotenoid, soluble protein, soluble sugar, superoxide (O2*-), hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents as well as the activities of superoxide dismutase (SOD), guaiacolperoxidase (POD), and catalase (CAT) were studied in the leaves of Salvinia natans plants on 10 days after treatment. With the increase of the Ni2+ concentrations, exposure of the plants revealed that, (1) the addition of Ni2+ affected the absorption of mineral nutrients, it mainly increased the absorption of Ca2+, Na+, Zn2+, Fe3+ and Mg2+, while reduced that of Mn2+, Mo2+, P and K+. (2) The content of chlorophyll, carotenoid, soluble protein and soluble sugar content as well as activities of SOD and CAT decreased gradually.

[Effects of Cu2+ stress on leaf physiological indice and ultrastructure of Potamogeton malaianus].

With solution culture, this paper studied the toxic effects of different concentrations of Cu2+ (0, 2, 4, 6, and 8 mg x L(-1)) on the chlorophyll content, soluble protein content, protective enzyme activities, active oxygen generation, and ultrastructural changes in Potamogeton malaianus leaf. The results showed that with increasing concentration of Cu2+, the chlorophyll, carotenoid and soluble protein contents and superoxide dismutase (SOD) and peroxidase (POD) activities decreased, catalase (CAT) activity increased first and decreased then, while O2-*, H2O2, MDA and soluble sugar content increased. SDS-PAGE revealed that Cu2+ induced the disappearance or the decrease of the expression amount of four polypeptides with apparent molecular weights of 60.