More than colorful: phosphorus allocation to major chemical fractions shifts during leaf development in species exhibiting delayed greening

The colorful “delayed leaf greening” is a common but overlooked phenomenon in phosphorus limited environments in habitats in tropical, subtropical and temperate forests, while the physiological mechanism underpinning it remains unclear. It is important to understand how allocation of phosphorus to major leaf phosphorus fractions shifts during leaf development, as a strategy for utilizing phosphorus efficiently. We measured concentrations of leaf nitrogen and phosphorus and five chemical phosphorus fractions, and leaf metal element concentrations (K,Ca, Mg, Mn, Fe, Cu, Zn and Se) in young and mature leaves of six woody plants exhibiting delayed greening in China. We also measured leaf mass per area, photosynthetic rate, photosynthetic phosphorus-use efficiency, and soil nutrient concentrations. The results indicate six species exhibiting delayed greening had different leaf phosphorus concentrations during leaf development, but not leaf nitrogen concentrations. We further show major leaf chemical phosphorus fractions like metabolite phosphorus, nucleic acid phosphorus and lipid phosphorusshowed differences in young and mature leaves. This study provides new insight to investigate the roles of different phosphorus fractions in young and mature leaves, and how the allocation shifts for plants to utilize phosphorus.