The Variations of Leaf delta C-13 and Its Response to Environmental Changes of Arbuscular and Ectomycorrhizal Plants Depend on Life Forms

Arbuscular mycorrhiza (AM) and ectomycorrhiza (ECM) are the two most common mycorrhizal types and are paid the most attention to, playing a vital common but differentiated function in terrestrial ecosystems. The leaf carbon isotope ratio (delta C-13) is an important factor in understanding the relationship between plants and the environment. In this study, a new database was established on leaf delta C-13 between AM and ECM plants based on the published data set of leaf delta C-13 in China's C-3 terrestrial plants, which involved 1163 observations. The results showed that the differences in leaf delta C-13 between AM and ECM plants related closely to life forms. Leaf delta C-13 of ECM plants was higher than that of AM plants in trees, which was mainly led by the group of evergreen trees. The responses of leaf delta C-13 to environmental changes were varied between AM and ECM plants. Among the four life forms, leaf delta C-13 of ECM plants decreased more rapidly than that of AM plants, with an increase of longitude, except for deciduous trees. In terms of the sensitivity of leaf delta C-13 to temperature changes, AM plants were higher than ECM plants in the other three life forms, although there was no significant difference in evergreen trees. For the response to water conditions, the leaf delta C-13 of ECM plants was more sensitive than that of AM plants in all life forms, except evergreen and deciduous trees. This study laid a foundation for further understanding the role of mycorrhiza in the relationship between plants and the environment.