Variations and determinants of carbon content in plants: a global synthesis

Abstract. Plant carbon (C) content is one of the most important plant traits and is critical in the assessment of global C cycle and ecological stoichiometry. However, the global variation in plant C content remains poorly understood. We conducted a global analysis of the plant C content by synthesizing data from 4318 species to provide specific values of C content and to assess their variation across plant organs and life forms. Our results showed that C content varied markedly across plant organs. Plant organ C content ranged from 45.01 % in reproductive organs to 47.88 % in stems at global scales, which were significantly lower than a canonical value of 50 % that has been widely employed in previous studies. Plant C content in leaves was higher than that in roots. Across life forms, woody plants exhibited higher C content than herbaceous plants. Conifers, relative to broad-leaved woody species, had higher C content in roots, leaves and stems. Plant C content tended to decrease with the increasing latitude. The life form explained more variation of the C content than climate due to plant structural requirements. Our findings suggest that specific C content values from different organs and life forms may be more suitable to evaluate global vegetation C stock and plant ecological stoichiometry.