Effects of nighttime light on photosynthetic pigments and secondary metabolism of Ginkgo biloba L.leaves during the discoloration period
This study focused on the common street tree species Ginkgo biloba L.in China and set up three different intensities of nighttime light treatments:near light(T1,100-200 Ix),far light(T2,30-50 Ix),and no light(control;CK,0-5 Ix),to explore the impact of night light on the photosynthetic characteristics and secondary metabolism of Ginkgo biloba L.during the autumn color-change period(from October 1st to 30th).This study aims to provide a scientific basis for urban landscaping and landscape protection,and the results show that:(1)under the nighttime light T1 and T2 treatments,the content of chlorophyll a and xanthophylls and the quantum yield of non-regulated energy dissipation were all higher than those in the CK treatment,with T1＞T2＞CK from large to small,while the quantum yield of chlorophyll b and regulated energy dissipation were both lower than those in the CK treatment,with CK＞T2＞T1 from large to small.(2)Compared with the CK treatment,during the early stage of leaf coloration(1st-8th),the content of flavanols in Ginkgo under T1 and T2 treatments decreased by 4.7％and 4.3％,while the content of anthocyanins increased by 15.9％and 7.5％;nighttime light had different degrees of impact on chlorophyll fluorescence parameters.Among them,the initial fluorescence,maximum fluorescence,maximum photochemical efficiency,and photochemical quenching coefficient decrease(3.1％-28.9％),while the non-photochemical quenching coefficient increases(14.1％-18.3％).As the temperature decreased,the changing trends in the later stages of leaf coloration(15th-29th)were the opposite.Specifically,the content of anthocyanins in Ginkgo biloba L.under T1 and T2 treatments significantly decreased by 34.7％and 50.6％,while the maximum photochemical efficiency significantly increased by 58.5％and 56.4％.(3)Nighttime light had a significant impact on the contents of photosynthetic pigments and flavonoids(P＜0.01),and there was a significant negative correlation between photosynthetic pigments and anthocyanins(P＜0.01).In summary,nighttime light causes photo stress in Ginkgo biloba L.leaves,significantly affecting their photosynthetic pigments,flavonoid content,and chlorophyll fluorescence indices,thereby postponing the leaf coloration period and affecting the normal growth and development of the plant.
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万方数据
