National Natural Science Foundation of China (41701099); General projects of NSFC(32071760);Science and technology innovation fund project of Fujian agriculture and Forestry University (KHF 170002)
The ecological stoichiometric characteristics of silicon (Si) and calcium (Ca) play crucial roles in plant nutrient absorption, and thus impact the global biogeochemical cycle of Si and Ca. However, few were known about the stoichiometric characteristics of Si and Ca in the woody plant. In this study, using the collected data of Si and Ca of 803 woody plants in the world from the Plant Trait Database and published literature, the stoichiometric characteristics of Si and Ca in leaves of different woody plant life forms (evergreen plants, deciduous plants, coniferous plants and broad-leaved plants) and their relationships with latitude and climatic factors (mean annual temperature and mean annual precipitation) were investigated using the covariance analysis method. The results showed that:(1) the contents of Si and Ca in leaves of woody plants were highly variable at a global scale, and their contents were lower than those in China. In detail, the global geometric mean content of Si and Ca was 0.28 and 1.73 mg/g, respectively. (2) The contents of Si and Ca are varied among different life forms. The Si content and Ca/Si ratio of coniferous trees were significantly higher than those of broad-leaved trees, and the contents of Si, Ca in leaves of deciduous trees were significantly higher than those of evergreen trees; (3) With the increase of latitude and the decrease of mean annual temperature and precipitation, the contents of Si, Ca and Ca/Si in leaves of woody plants at the global scale increased significantly,while Ca/Si decreased significantly; (4) The responses of Si and Ca contents in leaves of different life forms to climate factors were varied. Except for Ca content of coniferous and deciduous trees, Si, Ca content in the life forms of evergreen plants and broad-leaved plants were significantly related to latitude and climate factors, and increased with the increase of latitude and decreased with the increase of mean annual temperature and precipitation. With the decrease of mean annual temperature, the decrease rate of Si content in leaves of evergreen and broad-leaved trees was significantly higher than that of deciduous and coniferous trees. From the perspective of ecostoichiometric characteristics, this study provides data basis for the development of ecological stoichiometric models at a global scale, and helps to better understand and simulate the effects of latitude and climate factors on the content of Si and Ca in plant leaves at regional and global scales.