| The effect of topping and fruiting at different node on plant physiology characteristics, activity of protecting enzymes(POD and SOD) in leaves, fruit yield and quality of muskmelon in greenhouse was studied. The experiment material was muskmelon Luhoutian No. 1. There were two experiments in this study and each has their own treatments. The first experiment included four treatments: Treatment 1,topping at 19th node; Treatment 2, topping at 23th node; Treatment 3, topping at 27th node; Treatment 4, no topping. The second experiment included three treatments: Treatment 1, fruiting at 10th node; Treatment 2, fruiting at 14th node; Treatment 3, fruiting at 18th node. The results were as follows:1. Fruiting and topping at reasonable node kept Chlorophy and Soluble protein content higher in leaves during middle and late period of fruit development,between 28th day and 49th day after pollination. The three fruiting treatments followed the same regulation: treatment 2 was best , treatmrnt 1 was second , treatment 3 was last, treatment 2 was distinctly higer than treatment 3 35 days after pollination and the difference between treatments became distinct 42 days after pollination. The four topping treatments followed the same regulation: treatment 3 was best, treatment 2 was second, treatment 1 was third, treatment 4 was last. Compared to treatment 2 ,treatment 3 distinctly promoted Chlorophy and Soluble protein content in leaves at high node(14th node,18th node) 42 days after pollination, treatment 1 and treatment 4 distinctly decreased Chlorophy and Soluble protein content in leaves at low node(second node, 6th node). 2. Fruiting and topping at reasonable node kept Vitamin C content higher in leaves during middle and late period of fruit development, between 28th day and 49th day after pollination. The three fruiting treatments followed the same regulation: treatment 2 was best , treatmrnt 1 was second , treatment 3 was last, treatment 2 was distinctly higer than treatment 1 and treatment 3 and the difference between treatment 1 and treatment 3 decreased as the fruit grew. The four topping treatments followed the same regulation: treatment 3 was best, treatment 2 was second, treatment 1 was third, and treatment 4 was last. Compared to treatment 2 ,treatment 3 distinctly promoted Vitamin C content in leaves 42 days after pollination, treatment 1 had no difference, and treatment 4 distinctly decreased Vitamin C content in the leaves at low node(second node).3. Fruiting and topping at reasonable node kept the photosynthetic rate of muskmelon leaves higher during late period of fruit development. The three fruiting treatments followed the below regulation :Compared to treatment 2, treatment 1 decreased the photosynthetic rate of leaves at high node(10th node, 14th node, 18th node), treatment 3 decreased the photosynthetic rate of leaves below 18th node, so the best fruiting node is 14th node. The four topping treatments followed the below regular :compared to treatment 2, treatment 3 distinctly increased the photosynthetic rate of leaves at high node(10th node, 14th node, 18th node), treatment 1 distinctly decreased the photosynthetic rate of leaves at low node(second node, 6th node),and treatment 4 distinctly decreased the photosynthetic rate of all leaves below 18th node, so the best topping node was 27th node.4. Fruiting and topping at reasonable node increased the root activity efficiently. The three fruiting treatments followed the below regular:compared to treatment, treatment 3 increased the root activity during beginning period of fruit development (7 days after pollination),but decreased the root activity during the late period of fruit development(42days after pollination), the root activity of treatment 1 was distinctly lower than the other treatments, so the best topping node was 14th node. The four topping treatments followed the below regular:compared to treatment 2, the root activity of treatment 3 increased distinctly during the middle and late period of fruit development, the root activity of treatment 4 decreased distinctly during the late period of fruit development(42th day after pollination), the root activity of treatment 1 distinctly lower than the other three treatments durng the whole fruit development period, so the best topping node was 27th node.5. Fruiting and topping at reasonable node delayed the time when POD activity increased quickly. The three fruiting treatments followed the below regulation: POD activity of treatment 3 was first ,treatment 1 was second ,treatment 2 was last, and the difference between them was distinct. The four topping treatments followed the below regulation: POD activity of treatment 4 is the highest and most of the time distinctly higher than other treatments. Treatment 1 is lowest before 28 days after pollination, then increased quickly and finally had no difference with treatment 4 and distinctly higher than other treatments. During middle period of fruit development (28th day to 35th day after pollination),POD activity of leaves at low node(second,6th node,10th node)of treatment 3 is distinctly lower than treatment 2,and that ofleaves at high node(14th node, 18th node) had difference with treatment with treatment 2.6. Fruiting and topping at reasonable node kept SOD activity high.During middle and late period of fruit development ,the three fruiting treatments followed the below regulation: SOD activity of all leaves of treatment 2 was first , treatment 1 was second ,treatment 3 was last and the difference between them was distinct. The four topping treatments followed the bellow regulation: compared to treatment 2 ,treatment 3 distinctly increased SOD activity of leaves at low node(second, 6th node,10th node)from 35th day to 49th day after pollination and that of leaves at high node (14th node,18th node)from 42th day to 49th day after pollination. Treatment 1 and 4 distinctly decreased SOD activity of leaves at low node(second, 6th node) all the time and that of leaves at high node(14th node,18th node) from 42th day to 49th node.7. Fruiting and topping at reasonable node increased the yield of muskmelon. The tree fruting treatments followed the below regulation: treatment 2 is first,treatment 1 is second ,treatment 3 is third, yield of treatment 1 had no difference with treatment 2 ,and both treatment 1 and treatment 2 are distinctly higher than treatment 3. The four topping treatments followed the below regulation: yield of treatment 2 had no difference with treatment 3, yield of treatment 1 had no difference with treatment 4, and both treatment 2 and treatment 3 are distinctly higher than treatment 1 and treatment 4.8. The fruit qulity of four topping treatments had no distinct difference.9. Fruiting at reasonable node improved the fruit quality of muskmelon. The three fruiting treatments followed below regulation: about Free Amino acid, Soluble sugar, Sucrose, Fructose and Soluble solid content in fruit ,treatment 2 distinctly higher than other treatments, and treatment 1 had no distinct difference with treatment 3. Vitamin C content in fruit of treatment 1 had no distinct difference with treatment 2 and both of them are distinctly higher than treatment 3. Soluble protein in fruit of treatment 2 had no distinctly difference with treatment 3 and both of them are distinctly lower than treatment 1.10. The result of this experiment showed: If fruited at 14th node,the best topping node was 27th. If topped at 27th node,the best fruiting node was 14th. The result suppied scitific thereunder for growth and management of muskmelon in greenhouse. |
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