ABSTRACT
OBJECTIVE: To study the effects of shading on photosynthetic physiology and chlorophyll fluorescence of Pinellia ternata. METHOD: Plant growth, chlorophyll content, net photosynthetic rate (P(n)) and chlorophyll fluorescence in P. ternata were investigated under different shading treatments (0%, 70% and 90%) when it grew about 15 cm high. RESULT: The results showed that fresh weight of a tuber, height, leaf length, width, leaf area, specific leaf area (SLA) and contents of chlorophyll content were enhanced after shaded, and chlorophyll a/b rate declined. Compared with control, net photosynthetic rate, light compensation point (LCP) and light saturation point (LSP) of P. ternata decreased after shading, but apparent quantum yield (AQY) increased; quantum yield of PS II (PhiPS II), minimal fluorescence (F(o)), maximal fluorescence (F(m)), intrinsic photochemical efficiency of PS II (F(v)/F(m)) and photochemical quenching coefficient (qP) were enhanced. CONCLUSION: Compared with control, all data indicated that there were distinctive differences between the height, SLA, chlorophyll content, P(n) and chlorophyll fluorescence characteristics under the shading treatments (70% and 90%), the fresh weight of a tuber increased after 70% shading, and provided better environmental conditions for the growth of P. ternata.
