Effects of Low-Light Environments on the Growth and Physiological and Biochemical Parameters of Indocalamus and Seasonal Variations in Leaf Active Substance Contents

Abstract

Indocalamus, characterized by its expansive leaves, low height, strong reproductive capacity, and abundant bioactive compounds, has extensive utility in the realms of food processing, the manufacturing of packaging materials, and the advancement of novel pharmaceuticals. Two light environments, CK (100% full light) and ST (50% full light), were established to explore the effects of low-light environments on the reproductive ability, morphological characteristics, photosynthetic properties, and leaf active substances of 14 Indocalamus species. The findings revealed that in comparison to the CK treatment, for 14 species of Indocalamus under the ST treatment, (1) the diameter, single leaf area, and leaf area index increased by 8.27%, 8.14%, and 17.88%, respectively; (2) the net photosynthetic rate decreased by 15.14%, and the total chlorophyll contents increased by 20.25%; and (3) the total flavonoid contents increased by 18.28% in autumn, the total polyphenol contents increased by 48.96% in spring, and the total polysaccharide contents increased by 31.44% and 30.81% in summer and winter, respectively. In summary, Indocalamus are adapted to survive in low-light environments; the growth and physiological indices differ significantly between the two light environments, and the low-light environment can effectively promote the growth and development of the leaves. Furthermore, the leaves are rich in flavonoids, polyphenols, polysaccharides, and active substances, which are affected by the light intensity and the season to varying degrees, and autumn and winter are the best times for harvesting the leaves. The leaves of I. hunanensis and I. lacunosus are richest in flavonoids and polyphenols, while the leaves of I. kunmingensis cv. fuminer are richest in polysaccharides. The main findings of this study demonstrate that Indocalamus has strong shade tolerance and tremendous leaf value, laying the foundation for broadening the application of their leaves and for their industrial development in understory composite planting systems.