Comparison of growth,photosynthetic,and chlorophyll fluorescence characteristics for different prove-nances of Arcocarpus fraxinifolius
We examined the growth,photosynthetic pigment content,photosynthetic response parameters,and chlorophyll fluorescence parameters of 1-year-old seedlings of three provenances of Arcocarpus fraxinifolius(Hechi Duan,Baise Tianlin and Xishuangbanna)and analyzed the influences of climatic factors of the provenance sites.The results showed that:(1)The maximum net photosynthetic rate(Pmax),light saturation point(LSP),chloro-phyll a(Chla),chlorophyll b(Chlb),carotenoid(Car),PS Ⅱ primary light energy conversion efficiency(Fv/Fm),electron transfer efficiency(ETR)and actual photochemical efficiency(ΦPSⅡ)of Hechi Duan provenance were significantly higher than those of the other two provenances(P<0.05),while apparent quantum efficiency(AQY),light compensation point(LCP)and luminescence chemical quenching coefficient(NPQ)showed no variation among the three provenances(P>0.05).It indicated that Hechi Duan provenance had a wider range of light adaptation,higher light energy conversion efficiency and higher maximum net photosynthetic rate,which was consistent with its growth performance.(2)The climatic factors of the provenance site had a significant impact on the growth characteristics and photosynthetic characteristics.The Hechi Duan provenance,whose climatic factors(average annual rainfall and annual sunshine duration)were closer to that of the experimental site,showed the best growth and the largest Pmax.The Xishuangbanna provenance with larger difference in climatic factors to the experi-mental site had the lowest growth and the smallest Pmax.It is concluded that genetic differences caused by climatic differences of provenance sites are one of the main reasons responsible for the differences in growth and photosyn-thetic characteristics of A.fraxinifolius among different provenances.