地膜覆盖导致番茄早衰的生理机制研究

研究了地膜覆盖导致番茄早衰的生理机制,结果表明:地膜覆盖使番茄叶片叶绿素含量在采收始期以前增加,在采收盛期以后显著降低,使伤流量在全生育期都增加,使叶片光合速率和根系活力在采收始期以前提高,在采收盛期以后降低。地膜覆盖还使叶片氮、磷和钙素含量在全生育期都提高,叶片钾素含量在青熟期之前提高,在采收始期以后降低,效应以收获结束期最为显著;地膜覆盖使叶片叶绿素含量在全生育期都降低,效应也以收获结束期最大。生育后期植株发生早衰,可能与植株缺钾及可溶性糖在叶片中的积累有关。

On Physiological Mechanism of Early Aging Caused by Plastic Mulching on Tomatoes

The experiment was conducted to probe into physiological mechanism of early aging caused by plastic mulching on tomatoes. The result showed that plastic mulching made chlorophyll content in tomato leaves increase before initial harvest stage but decrease remarkably after harvest peak stage, made plant bleeding sap increase all the stages, and made photosynthesis of leaves as well as vigor of roots increase before initial harvest stage but decrease after harvest peak stage. It also increased contents of nitrogen, phosphorus and calcium on dry matter basis in leaves, and increased potassium content before green ripe stage but decreased that after initial harvest stage, and the effect was most remarkable at final harvest stage. The covering made magnesium content in leaves decrease at all the growth stages, and the effect was also most remarkable at final harvest stage. The tomato plants arise early aging at last growth stages. It seems that early aging was related to insufficiency ofpotassium, which resulted in soluble carbohydrate accumulation in leaves.