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

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• 作者：Yan-xiu MIAO ; ^{miaoyanxiu@163.com" class="auth_mail" title="E-mail the corresponding author} ; Xiao-zhuo WANG ; Li-hong GAO ; Qing-yun CHEN ; ^{caucqy@163.com" class="auth_mail" title="E-mail the corresponding author} ; Mei QU ; ^{qumei@cau.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：cucumber ; photosystem II ; photosystem I ; electron transport
• 刊名：Journal of Integrative Agriculture
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：15
• 期：1
• 页码：87-100
• 全文大小：1550 K

文摘

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 (ETR_II) and in PSI (ETR_I) by 79.4 and 66.3%, respectively, increased non-light induced non-photochemical quenching in PSII (Φ_NO) and limitation of donor side in PSI (Φ_ND) 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_II and ETR_I by 176.9 and 127.0%, respectively, promoted photosystems activity and enhanced linear electron transport by elevating electron transport from Q_A 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.