[Effects of NaCl stress on seedling growth and IAA metabolism of sweet potato and its relation to salt-tolerance].

Seedlings of three sweet-potato (Ipomoea batatas) cultivars with different salt-tolerance were stressed with different concentrations of NaCl during the seedling stage. Plant growth, leaf area growth, and IAA content decreased with increasing NaCl concentration, while the activities of POD and IAA oxidase increased. The extent of plant growth, leaf area growth and IAA content decrease and the extent of POD and IAA oxidase activity increase were larger in sensitive cultivar than those in moderately tolerant and tolerant cultivars.

[Effects of different mycorrhizal fungi on physiological metabolism of tobacco seedlings].

Tobacco seedlings were inoculated with VA mycorrhizal fungi in natural soil. The results showed that compared with the control, the contents of nitrogen, phosphorus, potassium and chlorophyll, nitrate reductase activity, and protein in leaves were higher, malondialdehyde(MDA) and hydrogen peroxide(H2O2) decreased, while the activities of superoxide dismutase(SOD), catalase(CAT), and peroxidase(POD) increased. Meanwhile, seedlings were inoculated with two strains of ectomycorrhizal fungi respectively, and the above physiological indices trended the same changes.