Two soybean (Glycine max) varieties Xudou 18 (waterlogging-sensitive) and Nannong 1138-2 (waterlogging-tolerant) were used to study the regulation effect of spraying sodium diethyldithiocarbamate (DDTC) on photosynthetic indexes, activities of sucrose-metabolizing enzymes of leaves and contents of carbohydrates in leaves, roots and nodules. The results showed that waterlogging stress resulted in an obvious decrease in shoot dry weight, root dry weight and nodule dry weight of soybean plants, net photosynthetic rate (Pn), stomatal conductance (Gs), intercellular CO2 concentration (Ci), transpiration rate (Tr) of leaves, starch content of roots and sucrose and starch contents of nodules. Nannong 1138-2 had smaller decrease in plant dry weight, gas exchange parameters and starch content of roots than Xudou 18, while there was a similar change in sucrose and starch contents of nodules between two varieties. Conversely, waterlogging stress significantly increased sucrose phosphate synthetase (SPS), sucrose synthetase (SS) (synthesis), SS (cleavage), acid invertase (AI) activities and solube sugars, sucrose and starch contents of leaves and solube sugars and sucrose contents of roots. Nannong1138-2 exhibited smaller increase in activities of SS (cleavage), AI and concentrations of solube sugars, sucrose and starch of leaves, but a greater increase in SPS and SS (synthesis) activities of leaves. DDTC treatment increased plant dry weight of two varieties under waterlogging stress, and thus alleviated the growth inhibition of waterlogging stress on soybean plants. DDTC treatment increased gas exchange parameters of leaves, the activities of SPS and SS (synthesis) and decreased the activity of SS (cleavage) of leaves, and further improving the transportation of sucrose from leaves to roots and nodules under waterlogging stress. In addition, DDTC treatment increased soluble sugars, sucrose and starch contents of roots and sucrose and starch contents of nodules, indicating that DDTC treatment played an important role in the regulation of growth and physiological process of carbon metabolism of soybean plants under waterlogging stress.

In order to assess the genetic diversity of peanut in Jiangsu Province,133 accessions of peanut landraces were evaluated by 25 SSR markers.93 alleles were amplified,and the average number of alleles per locus was 3.72.The polymorphic information content (PIC) of each primer varied from 0.066 to 0.749 with an average of 0.374.Shannon's information index of each primer varied from 0.161 to 1.385 with an average of 0.671.The similarity coefficients of 133 peanut landraces varied from 0.416 to 1.000 with an average of 0.830.The order of average similarity coefficient of 4 types of peanut was Arachis hypogaea L.var.hypogaea (0.899) ＞ var.hirsute (0.776) ＞ var.vulgaris (0.710) ＞ var.fastigiata (0.700).Cluster analysis with UPGMA showed that the landraces could be divided into three groups at 0.600 of genetic similarities coefficient.The results showed that there were rich genetic diversity of peanut landraces in Jiangsu Province,and the genetic diversity was significantly lower among the var.hypogaea than those of the other three types.The result of cluster analysis had important significance for efficiently using of these peanut landraces.