Microstructure and Light-response Parameters of Flowering Bamboo (Phyllostachys iridescens) Blades

To study the physiological function changes during bamboo flowering, and explore the methods of rejuvenation after flowering, we selected different Phyllostachys iridescens non-flowering bamboo blades, heteromorphic blades and normal blades from flowering bamboo stands, and observed their anatomical structures and photosynthetic parameters. Results showed that during the phase change from vegetative to reproductive growth, the blades of flowering bamboo appeared smaller and thinner and the distance between adjacent vascular bundles tended to increase, while the vascular bundle transverse area and stomatal density decreased. The overall thickness, upper epidermis thickness, vascular bundle transverse area and stomatal density of the heteromorphic blades were 71.59%, 87.40%, 77.79% and 73.56% that of the non-flowering bamboo blades, respectively, while the distances between adjacent vascular bundles were 19.34% larger than that of non-flowering bamboo blades, leading to reductions in photosynthesis and transpiration of flowering bamboo blades. Light-response parameters such as the light saturation point, apparent quantum yield, and maximum photosynthetic rates of heteromorphic blades were 67%, 40.5% and 8.27% that of non-flowering blades, respectively, 900, 0.015 and 1.22 μmol·m^-2·s^-1, and the light compensation point of the heteromorphic blades (85.11 μmol·m^-2·s^-1) was 208.5% higher than that of non-flowering blades. However, the light-response parameters of normal blades of flowering bamboo were somewhere in between. The weakened leaf structure and function alienation exacerbated by the flowering bamboo eventually led to perennial bamboos, which could not grow normally after flowering.