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光照强度驱动典型阴生植物三七的生理生态响应特征

花匠小妙招
2024-12-16 21:49

Abstract:

This paper aims to explore the ecophysiological characteristics of a typically shade-tolerant species Panax notoginseng in response to different light intensities. Different light levels were applied to P. notoginseng. The physiological traits, morphological traits and growth indicators were comparatively analyzed in the plants grown under 46.5% light transmittance (LT), 21.8% LT, 9.70% LT, 5.10% LT and 2.80% LT. Correlations among the ecophysiological characteristics, plasticity indices and principal component analysis (PCA) were conducted in the study. The results showed that morphological characteristics (plant height, stem thickness, leaf area per plant), biomass and relative growth rate (RGR) of P. notoginseng were decreased under high light condition (46.5% LT and 21.8% LT) and low light condition (5.10% LT and 2.80% LT). With the decrease of light intensity, root biomass ratio (RMR), maximum net photosynthetic rate (Pn-max), stomatal conductance (Gs), light compensation point (LCP) and dark respiration rate (Rd) declined, while leaf area ratio (LAR), specific leaf area (SLA), stem biomass ratio (SMR) and leaf biomass ratio (LMR) showed an increasing trend. These changes were able to reduce light energy capture and light energy consumption of P. notoginseng in high light condition, while light energy capture and consumption in low light condition were enhanced. In addition, the phenotypic plasticity indices of morphological characteristics of shade-tolerant species P. notoginseng were less than 0.5, while the phenotypic plasticity indices of photosynthetic physiology (Pn-max, Gs, LCP, Rd), LAR and root biomass were greater than 0.5, and the plasticity indices were 0.581, 0.558 and 0.574 for Pn-max, Gs and LCP, respectively. The results indicated that photosynthetic physiological characteristics, LAR and root biomass were most responsive to light intensity. Moreover, studies have found that approximately 10% LT was suitable for the growth of P. notoginseng. In a word, under low light conditions, P. notoginseng mainly adopts a conservative strategy for decelerating carbon acquisition and carbon consumption, while under high light conditions, P. notoginseng mainly adopts an adventurous strategy for rapid carbon acquisition and carbon consumption. The study elucidates the adaption strategies of P. notoginseng in response to different light intensities and provides a theoretical basis for the high-quality and efficient cultivation of P. notoginseng.