Abstract
Wild chrysanthemums and chrysanthemum cultivars (Chrysanthemum morifolium Ramat.) form non-glandular trichomes on the leaves. By scanning electron microscope and light microscope, the density and length of non-glandular trichomes on the leaves were measured. Highly significant differences in the density on the abaxial leaf side were found among 10 wild chrysanthemums. More and longer non-glandular trichomes were formed on the abaxial leaf side than the adaxial side. Similar traits were observed among 20 chrysanthemum cultivars but the degree of differences in the variation was minor. C. weyrichii (Maxim.) Miyabe & T. Miyake line 8913 had longer and characteristic non-glandular trichomes compared with other wild chrysanthemums. The densities in C. weyrichii line 8913 and cv. ‘Pingguoxiang’ were less than 0.3 per mm2 leaf area. The densities in cv. ‘Chrysanthemum Tsukuba No. 1’ and cv. ‘Oki-no-shiranami’ was higher than those other chrysanthemum cultivars. They are interspecific hybridizations between C. morifolium and C. pacificum that was extremely hairy. The density of non-glandular trichome may be inherited. Non-glandular trichomes were initiated by the enlargement of single epidermal cells followed by anticlinal devision on leaf primordia in cv. ‘Jimba’. The head of non-glandular trichome was spindle-shaped on developing leaves but became a flat ellipse on expanded leaves. The density decreased as the leaf expanded.
