樟树失绿黄化症的研究

Study on the Chlorosis of Camphor Tree

滨海地区石灰性土壤樟树失绿黄化症,主要起因于土壤条件,即土壤pH高,HCO3-多,土壤有机质含量低,从而影响了土壤中铁的活化和吸收;另一方面植株大量吸收磷素,使植株体内磷铁比失调,影响铁的运转,导致叶片失绿。建议用单叶叶绿素计读数SPAD值来描述樟树失绿黄化程度,当叶绿素计读数SPAD值大于30,即为正常;小于20即为黄化,介于20与30之间,越靠近30,黄化概率越小;越靠近20,黄化概率越大。

The chlorosis of camphor-tree（Cinnamomum camphora （L） Presl） growing in calcareous soils of coastal plain resulted largely from the soil conditions, and the most important factors of which were higher soil pH, more HCO3^- and less OM. Under such conditions, available soil iron was inactivated, subsequently preventing the plant roots from absorbing Fe. On the other hand, a larger amount of P was absorbed by these plants than the non-chlorosis plants from the soils,resulting in an imbalance of Fe to P and inhibiting Fe transportation within these plants. It was suggested that the leaf chlorosis degree of camphor-tree was measured by the portable chlorophyll meter （model SPAD-502）. When leaf SPAD value was exceed 30, it was normal;and when SPAD value was less than 20, it was chlorosis; and when SPAD value was between 20 and 30, especially near 30 the chlorosis probability was less, while nearer 20, the ehlorosis probability was more.