Analyses on photosynthetic characteristics and growth rate of Aquilaria sinensis seedlings from different provenances under shading conditions
Taking one-year-old seedlings of three provenances ( Dabai, Xiaobai and Dahuang) of Aquilaria sinensis ( Lour.) Spreng. from Maoming of Guangdong Province and one provenance of A. sinensis from Yunnan Province as research objects, light and CO2 response curves of net photosynthetic rate ( Pn) , photosynthetic and gas exchange parameters, chlorophyll content and Chlo/6 value of seedling leaf of four provenances under different shading conditions [ relative irradiance 100% ( control, natural light intensity), 50%, 25% and 5%) were analyzed, and seedling' s relative growth rate (RGR) was also compared. The results show that Pn value of four provenances all increase with increasing of photosynthetic photon flux density, and Pn value of four provenances in the control all are higher than that in the treatment groups. And Pn value of four provenances gradually increase with rising of intercellular CO2 concentration or increasing of relative irradiance. With reducing of relative irradiance, the maximum photosynthetic rate, light compensation point, light saturation point, dark respiration rate, maximum electron transport rate, maximum carboxylation rate and triose phosphate utilization rate of four provenances all decrease or significantly decrease (P<0. 05) , while the apparent quantum yield slightly increases. Under relative irradiance 100%-25% conditions, with reducing of relative irradiance, chlorophyll content of four provenances significantly increase but their Chla/6 value significantly decrease, RGR of Dabai and Xiaobai provenances increase gradually and that of Dahuang provenance has an un-significant difference, but that of Yunnan provenance significantly decreases. Under relative irradiance 5 % condition, chlorophyll content of Dahuang and Yunnan provenances significantly decrease and their Chla/6 value significantly increase, and their RGR significantly decrease, while all seedlings of Dabai and Xiaobai provenances die. According to comparison result among provenances, it is suggested that there is a certain difference in photosynthetic parameters, chlorophyll content and relative growth rate among four provenances, in which, all indexes of Yunnan provenance generally are the lowest. In general, A. sinensis is a semi-sun plant, and has relatively strong adaptability to different light environments.
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万方数据
维普
