Fundamental research Funds of CAF(Grant No. CAFYBB2018MB015)
Leaf functional traits are closely related to plant growth strategies and resource utilization ability. In order to explore the adaptation strategies of psammophytes to environment in Hainan Island, the leaf functional traits of Vitex trifolia, Clerodendrum inerme, Lantana camara, Eupatorium odoratum, Stachytarpheta jamaicensis and Ipomoea pes-caprae and their relationships with soil chemical properties were analyzed. The results showed that the leaf functional traits of tropical psammophytes were different among species, which were affected not only by species but also by soil factors. The specific leaf area of species were in the order of herb>shrub>vine. The N/P ratio of leaves ranged from 7.78 to 10.85, suggesting that the growth of tropical psammophytes was restricted by soil N. The variation coefficient of Na content in leaves was the highest, ranging from 18.46% to 76.36%, indicating that species had a great difference in the absorption of Na+, which would affect its natural distribution in coastal sandy land. The specific leaf area, leaf dry matter content had negative correlations with K and Na contents in leaves, as well as N/P ratio of leaves with Na content in soil, Na content in leaves with soil organic carbon, total P and total K, implying that sandy plants adapted to salt stress through specific leaf area change. Therefore, applying soil fertilizer would be an important measure for rapid restoration of coastal sandy vegetation, and the Na+ content in leaves could be used as the main index for salt-tolerance screening of sandy plants in tropical coast.