库尔勒香梨黄化病机理研究

Study on the Mechanism of Yellow of Kuerle Fragrant Pear

2000年在库尔勒市香梨黄化病较重的兰杆乡、英下乡和阿瓦提乡进行定点定株调查分析。结果表明,造成库尔勒香梨黄化病的主要原因,一是土壤和水的pH值偏高,致使土壤中重碳酸根含量偏高,与土壤和叶片中的铁离子结合成盐而沉淀,不能被植株吸收利用,出现正常叶片和黄化叶片中铁离子含量相差甚微的状况;二是由于施肥不合理造成土壤和叶片中硝态氮含量偏高,致使土壤和叶片中的铁离子被固定而使叶片失绿;三是土壤和叶片中的锰、镁离子偏低,镁离子是叶绿素形成的核心,致使随叶片的黄化程度不同叶片中的叶绿素含量发生相应的变化;四是在同一个果园中,黄化树与非黄化树只有个体间的差异,树势强的相对树势弱的植株来说黄化病发生的要轻、要迟,3个香梨园中黄化病的发生与树龄无明显关系。

In 2000, We investigated and analyzed by fixed points and fixed plants in Langan country, Ying xia country and Awaty country, where yellow of Kuerle fragrant pear was serious. The results showed that following principal reasons caused yellow of fragrant pear. The first, high pH in soil and water caused high HCO_3^-in soil, which can combine with ironion in soil and leaf to salt to form sediment. So that plants can't absorb and utilize it, but the difference of ironion content between normal leaf and yellow leaf was slight. The second, because of irrationally replying fertilizer, high NO_3^-N content in soil and leaf led ironion in soil and leaf to being fixed to make leaf lose green. The third, Mg^(2+) was the core of forming chlorophyll. Lower Mn^(2+) and Mg^(2+) in soil and leaf caused chlorophyll content of leaf having corresponding change following different yellow extent of leaf. The fourth, in same orchard, there were only individual differences between yellow trees and normal trees. Yellow of strong trees came on more slighter and later than that of weak trees. Arising yellow had not apparent relation to the age of tree in three fragrant pear orchard.