Interactive Effects of Light Intensity and Nitrogen Supply on Shoot Emergence and Associated Photosynthetic Traits in Dendrocalamus latiflorus

Investigating light-nitrogen interactions during bamboo shoot bud germination of <i>Dendrocalamus latiflorus</i> provides a theoretical basis for regulating shoot emergence through optimized light intensity and nitrogen supply. This study further elucidates how such coupling effects can guide stand density adjustments in bamboo plantations. Additionally, it provides actionable insights for improving nutrient management strategies in practical bamboo cultivation systems. This study evaluated the effects of different nitrogen levels (1.5, 4.5, and 7.5 g·clump^-1) combined with varying light intensities (10%, 40%, and 100%) on shoot germination and physiological characteristics of bamboo. Two-way ANOVA revealed a significant interaction between light intensity and nitrogen concentration on bamboo shoot bud germination (<i>p</i> < 0.05). Under low nitrogen conditions, bamboo shoot bud germination was highest (3 buds·clump^-1) at 10% light intensity. However, under high nitrogen conditions, the highest germination (4.75 buds·clump^-1) occurred at 40% light intensity. Moreover, leaf carbon, nitrogen, and starch contents were positively correlated with shoot bud germination. Pearson correlation and path analyses indicated that total chlorophyll, chlorophyll a/b, photochemical quenching coefficient, sucrose, and leaf nitrate were the main photosynthetic traits associated with bamboo shoot bud germination. Among these, the photochemical quenching coefficient was the most critical factor. Based on this, the nitrogen management, nitrogen utilization, and low-light adaptability of <i>D. latiflorus</i> could be optimized.