Comparison of Density and Morphology of Glandular Trichome of Tobacco Leaves of Four Species at Different Collection Periods

To observe morphological characteristics of glandular trichome, we studied the relationship between the glandular trichome and the quality of tobacco and explored the appropriate collection period. Using scanning electron microscope (SEM), the density and morphological characteristics of four species of the flue-cured tobacco upper leaf glandular trichome in four collection periods were studied. The results showed that tobacco leaves had long trichomes (included single cell and multi-cellular gland head), short ones and epidermal hair. Long ones was dominate trichomes on the surface of leaf,while the density and quantity of short trichomes are steady. The density of the same species in four collection periods existed significant difference (P<0.05), the trichome density on the lower epidermis developed better than the upper epidermis. Under the same ecological conditions, among four species, the glandular trichome morphology of K326 was full, had head trichome and long trichomes had more percentage. The glandular trichome morphology of Honghuadajinyuan were flat, headless trichome had more percentage. The appropriate collection periods of upper leaves of K326 and Yunyan97 were no more than 14 days, that of Yunyan87 was no more than 7 days and it is suggested that Honghuadajinyuan should be collected as early as possible.