Research on Dynamic Change of Glandular Trichomes Density on Differrnt Burley Tobacco Leaves

The change of the shape and glandular trichome density on the leaves in mature period was studied using 6 different genotypes of burley tobacco as materials. The results showed that the total density of glandular trichomes on the leaf surface went down in this period. During 56～86 days after transplantation, the density of long handle trichomes decreased gradually and that of short handle trichomes greatly. The density of glandular trichomes differed obviously between 6 burley tobacco varieties. The trichome density on the upper leaves was higher than that on the middle leaves. Long handle tri- chomes were the principal type on the leaf surface of burley tobacco. With entering mature period, the percentage of long handle trichomes and their exudates increased. When tobacco leaf got overripe, glandular trichomes speeded up withering, consenescence and coming off.