Effects of supplemental nitrogen on physiological characteristics of Aloe vera seedlings under NaCl stress

Soil salinization is one of the important factors which adversely affect the crop growth and yield. Recently, use of saline land has become a hot research topic around the world. Our objective is to investigate the effect of supplemental nitrogen on physiological characteristics of aloe under saline conditions, which has both theoretical and practical significance in exploitation of coastal mudflats. In the greenhouse, pot experiment was conducted to study the effects of nitrogen on the electrolytic leakage and the content of ions, MDA, proline, soluble sugar of aloe（Aloe vera L.） under NaCl stress. The results showed that plant dry weight, content of K+,Ca2+ and accumulation of proline, soluble sugar were all increased while Na+ and Cl- uptake was restrained in leaves of aloe with application of NH4NO3 under NaCl stress. Both K+ and Ca2+ were mainly distributed in the younger leaves while Na+ and Cl- were compartmentalized into the old leaves with supplemental nitrogen function under NaCl stress. In the functional leaves, MDA content and electrolytic leakage decreased remarkably with NH4NO3 application under 200 mmol/L NaCl stress. Application of 11.25 and 15 mmol/L NH4NO3 showed better regulation on the physiological characteristics for aloe under NaCl stress. In some extent, high salt tolerance of aloe was improved by supplemental nitrogen, mainly caused by the ions compartmentation, accumulation of organic osmoticas in leaves and the nutrients balance in plant.