Genotypic variations in photosynthetic and physiological adjustment to potassium deficiency in cotton (Gossypium hirsutum)

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• 作者：Ning Wang^a ; Hanbai Hua^a ; A. Egrinya Eneji^b ; Zhaohu Li^a ; Liusheng Duan^a ; Xiaoli Tian^a ; ^{tianxl@cau.edu.cn}
• 关键词：Cotton ; Potassium deficiency ; Carbon metabolism ; Nitrogen metabolism ; Genotypic variation
• 刊名：Journal of Photochemistry and Photobiology B ; Biology
• 出版年：2012
• 期刊代码：67_10111344
• 类别：ch
• 出版时间：2 May, 2012
• 卷：110
• 期：Complete
• 页码：1-8
• 文件大小：289 K

摘要

A hydroponic culture experiment was conducted to determine genotypic variation in photosynthetic rate and the associated physiological changes in response to potassium (K) deficiency in cotton (Gossypium hirsutum L.) seedlings with contrasting two cotton cultivars in K efficiency. The K-efficient Liaomian18 produced 66.7%more biomass than the K-inefficient NuCOTN99^B under K deficiency, despite their similar biomass under K sufficiency. Compared with NuCOTN99^B, Liaomian18 showed 19.4%higher net photosynthetic rate (P_n, per unit leaf area) under K deficient solutions and this was associated with higher photochemical efficiency and faster export of soluble sugars from the phloem. The lower net P_n of NuCOTN99^B was attributed to higher capacity for nitrate assimilation and lower export of soluble sugars. Furthermore, NuCOTN99^B showed 38.4%greater ETR/P_n than Liaomian18 under K deficiency, indicating that more electrons were driven to other sinks. Higher superoxide dismutase (SOD) and lower catalase (CAT) and ascorbate peroxidase (APX) activities resulted in higher levels of reactive oxygen species (ROS; e.g. O₂^{鈭?/sup>and H₂O₂) in NuCOTN99B relative to Liaomian18. Thus, the K inefficiency of NuCOTN99B, indicated by lower biomass and net P_n under K deficiency, was associated with excessively high nitrogen assimilation, lower export of carbon assimilates, and greater ROS accumulation in the leaf.}