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Updated: Jun 3, 2026

Evaluation of Photosynthetic Behaviors by Simultaneous Measurements of Leaf Reflectance and Chlorophyll Fluorescence Analyses
Published on: August 9, 2019
Moderate shading improves photosynthetic growth traits and phenanthrene production in Oreorchis patens
Zhenghai Zhang1, Jingjing Zhao2, Ye Hua3
1Jilin Agricultural Science and Technology University, Jilin, 132109, China. zhangzhenghai888@jlnku.edu.cn.
Abstract:
Oreorchis patens is an endangered shade-adapted medicinal orchid whose pseudobulbs contain phenanthrenes with antitumor activity. Insufficient science-based light management has limited its artificial cultivation. We examined the effects of five sunlight transmittance (SLT) levels (3%, 23%, 46%, 74%, 90%) on photosynthetic traits, plant growth, and pseudobulb phenanthrene accumulation. Moderate shading at 46% SLT optimized net photosynthesis per leaf, pseudobulb biomass, root development, and leaf expansion. This treatment also yielded the highest per-unit-area phenanthrene yield, 93.5% higher than under 23% SLT. High light induced leaf chlorosis and premature senescence, whereas deep shade resulted in negative net photosynthesis; both extremes reduced survival rate. Our findings suggest that 46% SLT optimizes photosynthetic efficiency, biomass accumulation, and phenanthrene production, supporting light management for its cultivation.
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