Department of Life Sciences, Faculty of Sciences of Sfax, B.P. 1171, Sfax 3000, Tunisia.
J Agric Food Chem. 2009 Dec 23;57(24):11484-90. doi: 10.1021/jf901490f.
Field-grown olive trees (Olea europaea L. cv. Chemlali) were used over two growing seasons to determine the effects of different saline water irrigation levels on levels of proline and chlorophyll contents and activities of superoxide dismutase (SOD), polyphenol oxidase (PPO), ascorbate peroxidase (APX), and catalase (CAT). The plants were irrigated with fresh water (FW; ECe = 1.2 dS m(-1)) and saline water (SW; ECe = 7.5 dS m(-1)). Leaf water relations (relative water content, water potential), photosynthetic activity, and leaf chlorophyll content decreased under irrigation with saline water. In spring 2005, net photosynthesis of young leaves was 24.5 and 14.9 micromol m(-2) s(-1) in FW- and SW-treated plants, respectively. In old leaves, these rates were 20.2 and 12.2 micromol m(-2) s(-1), respectively. The relative reduction of net photosynthesis in SW-treated plants varied from 39 to 46% and from 39 to 61%, compared to FW-treated plants during the first and second crop seasons, respectively. The relative reduction of leaf chlorophyll (a + b) content under high water salinity level exceeds 50%, compared to FW-treated plants. However, proline content and activities of SOD, CAT, and APX increased under saline water irrigation. The increase of proline content was more important in leaves than in roots. In young leaves, the increment of antioxidant activities in SW-treated plants was 2.67, 3.61, and 1.85 times, respectively, for SOD, APX, and CAT, compared to FW-treated plants. From these results, interaction between antioxidant defense system and proline contents seems to be involved in the salt tolerance mechanisms of Chemlali olive tree.
在两个生长季节中，使用大田生长的油橄榄（Olea europaea L. cv. Chemlali）来确定不同盐水平灌溉对脯氨酸含量和叶绿素含量、超氧化物歧化酶（SOD）、多酚氧化酶（PPO）、抗坏血酸过氧化物酶（APX）和过氧化氢酶（CAT）活性的影响。植物用淡水（FW；ECe = 1.2 dS m(-1)) 和盐水（SW；ECe = 7.5 dS m(-1)) 灌溉。在盐水灌溉下，叶片水分关系（相对含水量、水势）、光合作用活性和叶片叶绿素含量下降。2005 年春季，FW 和 SW 处理的幼叶净光合速率分别为 24.5 和 14.9 μmol m(-2) s(-1)。在老叶中，这些速率分别为 20.2 和 12.2 μmol m(-2) s(-1)。与 FW 处理的植物相比，在第一个和第二个作物季节，SW 处理的植物的净光合速率相对降低了 39%至 46%和 39%至 61%。与 FW 处理的植物相比，高水盐度下叶片叶绿素（a + b）含量的相对减少超过 50%。然而，脯氨酸含量和 SOD、CAT 和 APX 的活性在盐水中灌溉时增加。脯氨酸含量的增加在叶片中比在根中更为重要。在幼叶中，与 FW 处理的植物相比，SW 处理的植物的抗氧化剂活性增加了 2.67、3.61 和 1.85 倍，分别为 SOD、APX 和 CAT。从这些结果可以看出，抗氧化防御系统与脯氨酸含量之间的相互作用可能参与了 Chemlali 油橄榄的耐盐机制。
