Non-structural carbohydrates (NSCs) required for bamboo shoot development, the critical stage that determines the yield of a bamboo stand, originate from the parent bamboo with the complex underground system. However, the metabolic mechanism of NSCs in the rhizome–culm system during bamboo shoot development remains unclear. In this study, we focused on the changes of NSCs in the rhizome–culm system and used anatomical, physiological, and biochemical methods to investigate the metabolism of NSCs in bamboo shoots of Phyllostachys edulis and the role of NSCs supply in the parent bamboo at different ages. The results showed that NSCs were accumulated and consumed from the bottom to the top in a bamboo shoot, which was consistent with the developmental pattern. The starch granules were stored in advance. The bamboo sheath stored starch from the dormant stage of shoot buds. The functions of culms and rhizomes showed age-dependent differences. Adult culms showed the highest capacity to provide NSCs, with more stored NSCs and higher β-amylase activity. Conversely, young culms seemed to prefer their growth, while old culms tended to store starch. Accordingly, adult rhizomes preferred sugar transport due to the lowest starch storage, lower ADP-glucose pyrophosphorylase (AGPase) activity, and higher β-amylase activity, while young and old rhizomes tended to prefer starch storage. These results provide a basis for further understanding of nutrient metabolism in bamboo stands.

Degradation of shoots, characterized by stunted growth and signs of water deficit, is common in bamboo stands. However, the specific mechanisms underlying water utilization in degrading shoots remain unclear. This study sought to address this gap by harvesting bamboo shoots and culms of Phyllostachys edulis ‘Pachyloen’, employing cytological and physiological techniques to compare water utilization mechanisms between healthy and degrading shoots, and investigating the water supply to bamboo shoots by the parent bamboo. The water pressure in the degrading shoots was markedly lower compared to that of the healthy shoots, and it declined as the degradation progressed, resulting in reduced water content and the cessation of guttation in the degrading shoots. In conditions of water deficit, the percentage of free water in bamboo shoots decreased while the percentages of bound and semi-bound water increased, with the proportion of semi-bound water reaching as high as 88.13% in the late stages of degradation. The water potential of parent bamboo culms of different ages varied at different times of the day and during different growth stages of bamboo shoots, showing a strong association with the development of bamboo shoots. Conversely, the correlation between changes in the water potential of bamboo shoots and their degradation patterns was found to be comparatively minimal. The weakening of the connection between the bamboo shoots and the parent bamboo culms may play a significant role in the degradation of the bamboo shoots. This is evidenced by a decrease in the fluorescence intensity of the nucleus in bamboo shoots and the degradation of genetic material. This study lays the foundation for future research into the mechanisms of bamboo shoot degradation.