title: Effect of soil salinity on physiological characteristics of functional leaves of cotton plants.
abstract: This study analyzes the effects of soil salinity on fatty acid composition, antioxidative enzyme activity, lipid peroxidation, and photosynthesis in functional leaves during the flowering and boll-forming stages of two cotton cultivars, namely, CCRI-44 (salt-tolerant) and Sumian 12 (salt-sensitive), grown under different soil salinity conditions. Saturated (C16:0 and C18:0) and unsaturated fatty acid (FA) contents (C18:1), as well as superoxide dismutase activity increased, whereas high-unsaturated FA (C18:2 and C18:3) decreased, with the increase in soil salinity. The production of malondialdehyde increased with increasing lipoxygenase (LOX) activity, indicating that LOX catalyzed FA peroxidation under salt stress. Soil salinity had no significant effect on catalase (CAT) and peroxidases (POD) activity in the salt-sensitive cultivar Sumian 12, but significantly increased CAT and POD activities in the salt-tolerant cultivar CCRI-44. Net photosynthesis and stomatal conductance of the cotton cultivars decreased in response to salt stress; however, CCRI-44 showed a smaller reduction in photosynthesis than Sumian 12. The results indicated that stomatal apparatus limited leaf photosynthetic capacity in the salinity-treated plants of both cultivars. The net photosynthetic rate, maximum photochemical efficiency, and photochemical quantum yield of the cotton functional leaves showed positive correlation with double-bond index (DBI). These results suggested that salt stress caused DBI reduction and decreased the photochemical conversion efficiency of solar radiation and, thereby resulting in lower net photosynthetic rates.
authors.affiliation: Key Laboratory of Crop Growth Regulation, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Guowei
authors.initials: G
authors.lastname: Zhang
authors.forename: Youhua
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Zhou
authors.forename: Yali
authors.initials: Y
authors.lastname: Meng
authors.forename: Binglin
authors.initials: B
authors.lastname: Chen
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D058506:Cambium / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D002374:Catalase / Q000187:drug effects / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D003368:Gossypium / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology*; D015227:Lipid Peroxidation / Q000187:drug effects; D008084:Lipoxygenase / Q000187:drug effects / Q000378:metabolism; D010544:Peroxidases / Q000187:drug effects / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D010940:Plant Proteins / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D058526:Plant Vascular Bundle / Q000187:drug effects / Q000201:enzymology / Q000502:physiology; D054712:Salinity; D012492:Salts / Q000494:pharmacology*; D012987:Soil; D013482:Superoxide Dismutase / Q000187:drug effects / Q000378:metabolism
chemical_list: D000975:Antioxidants; D005227:Fatty Acids; D010940:Plant Proteins; D012492:Salts; D012987:Soil; D010544:Peroxidases; D002374:Catalase; D008084:Lipoxygenase; D013482:Superoxide Dismutase