Response of chlorophyll fluorescence parameters of illicium lanceolatum to different light conditions

Abstract

Illicium lanceolatum is a unique plant in traditional Chinese medicine. The shikimic acid, extracted from I.lanceolatum, has functions of anti-inflammatory, analgesic and inhibiting platelet aggregation, arterial and venous thrombosis and cerebral thrombosis. It can also function as an intermediate for anti-virus and anti-cancer drugs. For example, it is a vital element of Oseltamivirphosphate for anti-Avian Influenza. Because of this, I.lanceolatum and other species in this genus have been given an unprecedented attention and have potential for further development and utilization. Previous studies have shown that photosynthetic efficiency restricted the biomass and limited the Shikimic acid content of I.lanceolatum seedlings. The primary objective of the study was to examine the physiological and biochemical foundation of growth and biomass accumulation of I.lanceolatum seedlings and to provide theoretical guidance for regular cultivation. The chlorophyll fluorescence kinetics technique was used in this study. The kinetics parameters of fast chlorophyll fluorescence were measured for 4-year-old I.lanceolatum seedlings in Zhejiang province of China, under different light shading treatments (0%, 50% and 80%) using a plant efficiency analyzer (PEA) and JIP-test. The results showed that the maximal photochemical efficiency of photosystem II(Fv/Fm) decreased as the shading level increased. The ratio of Fv/Fm for 50% and 80% shading treatments decreased by 1.34% and 2.79% respectively, comparing with the control (0% shading treatment). The density of reaction centers(RC/CS) decreased by 2.94% and 13.63% for 50% and 80% shading treatments respectively, comparing with the control, and the energy dissipation per RC (DIo/RC) increased by 2.2% and 62.9% respectively. ANOVA analysis showed that actual light use efficiency, the fraction of absorbed light in photochemistry (P), for I.lanceolatum leaf under 50% shading exhibited no significant difference from the control(P > 0.05). However, for I.lanceolatum leaf under 80% shading, there was a significant decrease of the fraction of absorbed light in photochemistry (P) (P < 0.01). We concluded that I.lanceolatum seedlings under 50% shading could enhance the actual light use efficiency. The results obtained have physiological and biochemical implications for ways to improve biomass accumulation and content of Shikimic acid of I.lanceolatum plants.