城市污染对国槐树体VB_2含量及瘤坚大球蚧种群影响的研究

瘤坚大球蚧EulecaniumgiganteaShinji近年来是我国城市林木的重要害虫。作者于 1 998～ 1 999年在太原市和太谷县城设点 ,测定了该蚧虫的寄主树木国槐Sophorajaponica ,体内维生素B2 (VB2 )的变化规律 ,用蚧虫的虫口密度和生物学节律相对照 ,分析了污染—VB2 含量—蚧虫种群消长之间的关系。结果证明 ,污染区国槐枝条和叶片的VB2 含量极显著地高于清洁区 ;VB2 的变化与虫口密度呈正相关关系 ,回归式为Y =1 50 7.76x-1 70 .56,相关系数r=0 .839。在一年中 ,VB2 的含量呈现两个高峰期 ,正好与该蚧虫的两个取食期相吻合。由此认为 ,污染使树体内VB2 含量增高很可能是促进该蚧虫种群增长的一个原因

THE EFFECT OF CITY POLLUTION ON VB_2 CONTENT IN TWIGS AND LEAVES OF SOPHORA JAPONICA AND ON THE POPULATION OF EULECANIUM GIGANTEA

Eulecanium gigantea Shinji(Homoptera: Coccidae)is an important pest in the cities of Northern China in recent years. Experimental districts were selected in Taiyuan City and Taigu County from 1998 to 1999. Vitamin B 2 (VB 2 ) was determined monthly in twigs and leaves of Sophora japonica, the most favorable host of the scale insect. The results showed that the population density and biological rhythm of the scale insect were contrasted with the content of VB 2 and the VB 2 content in the two pollution districts were significantly higher than that in the cleaning district. The more the city environment polluted, the more VB 2 content in the host tree was. A positive relativity between the density of the scale insect and the VB 2 contents was found. The regression equation was made out as Y=1507.76x-170.56, and the coefficient, r =0.839. From March to October, the two peaks of VB 2 content were corresponded to the two feeding and quick development stages of the scale insect. It was concluded that a higher VB 2 content in the host plant in some degree was benefit to the scale insect occurring greatly in the polluted city environment.