Physiological response mechanism of different salt-resistant rootstocks under NaCl stress in greenhouse

The growth, root activity, ion content and enzyme activity of two salt-resistant rootstock seedlings(Cucurbit ficifolia cv. ‘Heizinangua’, Lagenaria siceraria Standl. var. clavata Makino cv. ‘Chaofeng 8848’) were investigated to reveal physiological mechanism of different rootstocks with different salt-resistant under salt stress by using water culture in the greenhouse. The results show that under salt stress, the dry weights of shoot and root, root activity, the contents of Ca2+ and Mg2+ and the ratio of K+ to Na+ in leaves decrease significant under salt stress. The content of Na+ in leaves decrease but is significantly lower than that in stem and root. The activities of superoxide dismutase(SOD) and peroxidase(POD), and the content of malondlaldehyde(MDA) in ‘Chaofeng 8848’ white-flowered gourd have no obvious change, whereas those of ‘Heizinangua’ increase under salt stress. The Na+ pooled mostly in the root and stem under lower salinity(50 mmol/L NaCl), but in the stem under higher salinity(100 and 150 mmol/L NaCl). Limiting the translocation of Na+ from root and stem to leaf is the key physiological mechanism of salt resistance for two rootstocks. ‘Chaofeng 8848’ white-flowered gourd exhibits a better salt resistance by maintaining higher root activity than ‘Heizinangua’.