番木瓜植株镁钾含量变化与缺钾叶枯病的关系

采用田间调查、采样及其室内分析与田间试验相结合的方法,在低钾而高镁的土壤上,从植株各个部位探索番木瓜植株镁、钾营养变化对其生理性缺钾叶枯症的影响。结果表明,番木瓜叶枯症的发生,除与土壤有效钾缺乏有关外,Mg/K比值过高也是导致该症发生的一个重要原因。发生缺钾叶枯病的番木瓜植株,其根、茎、叶片、叶柄等器官含镁量均明显提高,施用钾肥后不但提高了植株的含K量,而且能抑制番木瓜植株对镁的吸收,从而协调平衡Mg/K比值,生理性缺钾叶枯症得到有效控制。

Relationship Between the Mg and K Contents and Potassium- deficient Leaf Blight of Papaya Plant

The effect of Mg and K contents on physiologically potassium-deficient leaf blight of papaya plant was studied by investigation and sampling in the fields with low K and high Mg and chemical analyses in the laboratory. The result indicated that the disease severity was related to high Mg/K ratio except for absolute K deficiency in soil. The root, stem, leaf and petiole had high Mg content when the plant was deficient in K. K application controlled the disease effectively because it inhibited Mg absorption of the plants and balanced Mg/K ratio.