Blue light is more essential than red light for maintaining the activities of photosystem Ⅱ and Ⅰ and photosynthetic electron transport capacity in cucumber leaves  

作　　者：MIAO Yan-xiu W ANG Xiao-zhuo G AO Li-hong C HEN Qing-yun QU Mei 

机构地区：[1]Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Agriculture and Biotechnology, China Agricultural University,Beijing 100193,P.R.China

出　　处：《Journal of Integrative Agriculture》2016年第1期87-100,共14页农业科学学报（英文版）

基　　金：supported by the Special Fund for Nonprofit Industry (Agriculture) Research Project (201303014);Earmarked Fund for Beijing Fruit Vegetable Innovation Team Project of Modern Agro-industry Technology Research System (GCTDZJ2014033007) in China

摘　　要：Blue and red lights differently regulate leaf photosynthesis. Previous studies indicated that plants under blue light generally exhibit better photosynthetic characteristics than those under red light. However, the regulation mechanism of related photosynthesis characteristics remains largely unclear. Here, four light qualities treatments （300 μmol m-2 s-1） including white fluorescent light （FL）, blue monochromatic light （B, 440 nm）, red monochromatic light （R, 660 nm）, and a combination of red and blue light （RB, R：B=8：1） were carried out to investigate their effects on the activity of photosystem II （PSII） and photosystem I （PSI）, and photosynthetic electron transport capacity in the leaves of cucumber （Cucumis sativus L.） seedlings. The results showed that compared to the FL treatment, the R treatment significantly limited electron transport rate in PSII （ETR11） and in PSI （ETR1） by 79.4 and 66.3%, respectively, increased non-light induced non-photochemical quenching in PSII （q^No） and limitation of donor side in PSI （φND） and reduced most JIP-test parameters, suggesting that the R treatment induced suboptimal activity of photosystems and inhibited electron transport from PSII donor side up to PSI. However, these suppressions were effectively alleviated by blue light addition （RB）. Compared with the R treatment, the RB treatment significantly increased ETR, and ETR1 by 176.9 and 127.0%, respectively, promoted photosystems activity and enhanced linear electron transport by elevating electron transport from QA to PSI. The B treatment plants exhibited normal photosystems activity and photosynthetic electron transport capacity similar to that of the FL treatment. It was concluded that blue light is more essential than red light for normal photosynthesis by mediating photosystems activity and photosynthetic electron transport capacity.Blue and red lights differently regulate leaf photosynthesis. Previous studies indicated that plants under blue light generally exhibit better photosynthetic characteristics than those under red light. However, the regulation mechanism of related photosynthesis characteristics remains largely unclear. Here, four light qualities treatments （300 μmol m-2 s-1） including white fluorescent light （FL）, blue monochromatic light （B, 440 nm）, red monochromatic light （R, 660 nm）, and a combination of red and blue light （RB, R：B=8：1） were carried out to investigate their effects on the activity of photosystem II （PSII） and photosystem I （PSI）, and photosynthetic electron transport capacity in the leaves of cucumber （Cucumis sativus L.） seedlings. The results showed that compared to the FL treatment, the R treatment significantly limited electron transport rate in PSII （ETR11） and in PSI （ETR1） by 79.4 and 66.3%, respectively, increased non-light induced non-photochemical quenching in PSII （q^No） and limitation of donor side in PSI （φND） and reduced most JIP-test parameters, suggesting that the R treatment induced suboptimal activity of photosystems and inhibited electron transport from PSII donor side up to PSI. However, these suppressions were effectively alleviated by blue light addition （RB）. Compared with the R treatment, the RB treatment significantly increased ETR, and ETR1 by 176.9 and 127.0%, respectively, promoted photosystems activity and enhanced linear electron transport by elevating electron transport from QA to PSI. The B treatment plants exhibited normal photosystems activity and photosynthetic electron transport capacity similar to that of the FL treatment. It was concluded that blue light is more essential than red light for normal photosynthesis by mediating photosystems activity and photosynthetic electron transport capacity.

关 键 词：CUCUMBER photosystem II photosystem I electron transport 

分 类 号：S642.2[农业科学—蔬菜学] Q945.11[农业科学—园艺学]