Effect of different rootstocks on nitrogen metabolism of grafted cucumber leaves under NaCl stress

The growth and nitrogen metabolism of leaves of grafted cucumber and nongrafted cucumber at the adult plant stage were studied in hydroponic solutions under 80 mmol/L NaCl stress, and nonNaCl stress. The Cucurbita moschata hybrid of “360-3×112-2” and Cucurbita ficifolia were used as rootstocks, and cucumber cultivar, “Jinchun 2” was used as scion. The results show that the growth of grafted cucumber with C. moschata hybrids of “360-3×112-2”as rootstock is better than that of C. ficifolia under the NaCl stress. The nitrate and ammonium nitrogen contents, activity of glutamine synthetase and content of soluble protein in leaves of all treatments under the NaCl stress are higher than those of the control at the prophase, then lower than those of the control at the anaphase, while the activity of nitrate reductase is depressed at first, and then increased, but lower than that of the control all the time. These changes suggest that the ability of nitrogen metabolism of the plants is decreased under the NaCl stress, and the difference of the ability of nitrogen metabolism between all treatments is due to the root capacities of nitrogen uptake. Tested plants grafted on C. moschata hybrid of “360-3×112-2” has less growth inhibition, less reduce of nitrogen metabolism ability, therefore, it is a promising rootstock for high salt tolerance.