不同节位摘顶对日光温室厚皮甜瓜叶片衰老的影响

以日光温室栽培的蜜世界、鲁厚甜2号厚皮甜瓜品种为试材，通过分析不同摘顶植株叶片可溶性蛋白质(Pr)、叶绿素(Chl)、丙二醛(MDA)含量以及过氧化物酶(POD)活性变化，探讨了不同节位摘顶对厚皮甜瓜叶片衰老的影响。结果表明，在授粉后7d以内，两品种第18节、24节摘顶可使座瓜节位叶片维持较高的生理活性，第30节摘顶则明显偏低，表现为：前者叶片Pr、Chl含量明显高于后者，而MDA含量、POD活性则较低。授粉14d之后，两品种第24节摘顶延缓叶片衰老的效果明显优于第18节、30节摘顶。植株摘顶后，不同节位叶片生理指标的变化进一步证实，第24节摘顶可明显延缓叶片衰老。综合分析表明，24节左右为厚皮甜瓜合理摘顶节位，早熟品种可适当提高摘顶节位，而中晚熟品种应适当降低节位。

Effects of Different Topping Positions on Leaf Senescence of Muskmelon in Solar Greenhouse

Effects of different topping positions on leaf senescence were studied using the muskmelon varieties of Honey World and Luhoutian No. 2 grown in solar greenhouse by analyzing the contents of soluble protein (Pr), chlorophyll (Chl) and malondialdehyde (MDA), and the activity of peroxidase (POD). The results indicated that the physiological activities of leaves (adjacent to fruits) for the plants topped at the 18th and 24th nodes were stronger than those topped at the 30th node within 7 days after pollination. The contents of Pr and Chl of the former were obviously higher than the later, and the MDA content and POD activity were lower than that. After 14 days of pollination, the topping at the 24th node retarded leaf senescence, and its effect was superior to those at the 18th and 30th nodes. After being topped, the changes of physiological indexes for leaves at different nodes further confirmed that the topping at the 24th node can retard the leaf senescence remarkably. To sum up, about the 24th node was the proper topping position, and it can be raised for the premature cultivar while it should be reduced for the serotinous cultivar.