Foliar application of sodium gluconate enhances photosynthetic efficiency and photoassimilate accumulation in Dendrocalamus brandisii across vegetative phenological stages

Bamboo is widely distributed in the tropical, subtropical, and temperate regions worldwide and high productivity of bamboo forests are essential to the livelihoods of people. Small-molecule organic fertilizers, such as sodium gluconate (SG), are known to enhance crop growth and quality, their application in bamboo remains unstudied. Photosynthesis and its products are particularly important for bamboos. Thus, to investigate the effect of SG on the photosynthetic efficiency and photoassimilate accumulation in bamboo, the net photosynthetic rate (Pn), chlorophyll fluorescence (Fv/Fm and Fv`/Fm`), photosynthetic pigment, as well as soluble sugar and starch accumulation in response to foliar application of SG to Dendrocalamus brandisii at different vegetative phenological stages were determined. The results showed that SG application notably enhanced photosynthesis, with the most significant effects observed in young and mature leaves at branching and leafing stage in May and shooting stage in August. The soluble sugar content in young leaf was enhanced notably, contributing to enhancing stress tolerance. Thus, as the main or auxiliary agent to fertilizer, SG application to D. brandisii bamboo plantation was preferably scheduled in May and August. Potential limitations of excessive SG application was crucial to be considered. The findings shall furnish the theoretical basis for improving the management and production of bamboo plantations. • Effects of sodium gluconate (SG) on photosynthesis and photoassimilate accumulation in bamboo was systematically evaluated. • SG enhanced photochemical efficiency and chlorophyll notably at bamboo branching, leafing and shooting stages. • SG enhanced the photoassimilate accumulation and improved cold resistance of bamboo young leaf. • SG showed potential as a foliar fertilizer to improve bamboo productivity.