Effects Of Selenium To Physiological Indexes Of Peach, Jujube And Strawberry

To understand the effects of selenium in fruit, the peach (Prunus persica, cv. Luwangxian), jujube (Ziziphus jujuba, cv. winter-jujube) and strawberry (Fragaria ananassa, cv. Beinong 3) were employed as the materials. Se-fertilizer were sprayed with various concentrations of Na2SeO3 solution (0.0mg·L-0.5mg·L-1,1.0mg·L-1,2.5mg·L-1,5.0mg·L-1 and 10.0mg·L-1) at different stages of growth. Then the biological effects were observed. The results showed as follows:1) Strawberry had the highest absorption capacity of Se at the stages of leaf-expansion and full flower-opening. Peach had the highest absorption peak at shoot growth stage. The best stages of spray Se-fertilizer for winter-jujube were both of leaf-expansion and fruit-swelling ones. The abilities of Se absorption showed differences among the materials, strawberry was strongest, followed by winter-jujube.2) Spraying Se-fertilizer to leaves was one of methods for supplement selenium to peach, winter-jujube and strawberry fruits and suitable levels of selenium could alleviate their toxic responses to heavy metal (Cd and Pb). The optimum Se concentration was 10.0mg·L-1 to peach, which inhibited the accumulation of Cd and Pb contents in fruit, reduced 77.62% in Cd or 77.62% in Pb compared to the control, respectively. The optimum Se concentration for winter-jujube was 2.5-5.0 mg·L-1, reduced 40.81% in Cd or 50.32% in Pb compared to the control, respectively. The optimum Se concentration for strawberry was 5.0 mg·L-1, reduced 58.33% in Cd or 77.71% in Pb compared to the control, respectively. Compared with the control the Cd and Pb reduced 58.33% and 77.71%.3) The effects of Na2SeO3 at different level on the quality of peach, winter-jujube and strawberry during the cold storage were observed. The results showed that Na2SeO>3 could keep higher levels of the firmness of peach and jujube, in which 5.0-10.0mg·L-1 and 5.0mg·L-1 were the best concentrations. Meanwhile the contents of vitamin C, soluble sugar and titratable acid in cold storage fruits of peach, winter-jujube and strawberry were maintained.4) Spraying Se-fertilizer could bring beneficial effects to antioxidant enzymes in peach, winter-jujube and strawberry fruits at cold storage. The results showed that the selenium application inhibited effectively the contents of superoxide anion (·O2-) of the fruits during cold storage, and increased SOD,POD and GSH-Px activities as well as antioxidant capacity, the contents of MDA were inhibited.5) The effects of selenium on relative physiological indicators of respiratory metabolism and energy metabolism in peach, winter-jujube and strawberry during cold storage were investigated. The results showed that selenium application effectively inhibited the activity of pyruvate kinase (PK), and slowed down the progress of TCA, i.e. reduced the decomposition of glucose as well as the content of pyruvic acid. The hexokinase activity was inhibited (sign of mitochondrial respiration enzymes) by the glycolysis process. So the energy metabolism was reduced and the senescence of peach, winter-jujube and strawberry were delayed during cold storage. The optimum concentration was 10.0 mg·L-1 for peaches, or 2.5-5.0 mg·L-1 for winter jujube and strawberry.