Abstract
Dutch elm disease is the most common and destructive disease of the elm family. The pathogen of Ophiostoma novo-ulmi will systematically lead to the blockage of xylems and cavities, and will finally lead to the development of wilt symptoms. The present study aimed to compare the diameter size of vessels and the number of xylary rays in four species: Ulmus carpinifolia, Ulmus glabra, Zelkova carpinifolia and Celtis australis as important factors in host resistance to elm disease. To do this, some samples were randomly collected from 10 cm above the place of seedling’s inoculation. The test results showed that there was a significant difference at 1% probability level among the measured indicators in these four species, the maximum diameter of vessel and the maximum number of xylary rays belonged to U. carpinifolia. According to the results, Ulmus campestris was more sensitive towards Dutch elm disease as compared to the other three species, and C. australis had the greatest resistance to Dutch elm disease. Key words: Dutch elm disease, xylary rays, vessel, resistance
Highlights
Dutch elm disease was first observed in 1959 in forests of Golestan province, the Kansakuy and Kerenfecter Mountains, and spread to other areas (Iraqi et al, 2008)
In eugenic programs for elms’ resistance to Dutch elm disease, thousands of elms have been annually inoculated with Ophiostoma novo-ulmi
After preparation of microscopic slides, vessel’s diameter and the number of xylary rays in U. campestris, U. glabra, Z. carpinifolia, and Celtis australis were measured under OLYMPUS (BX51) microscope
Summary
Dutch elm disease was first observed in 1959 in forests of Golestan province, the Kansakuy and Kerenfecter Mountains, and spread to other areas (Iraqi et al, 2008). It is reported that vessels with smaller diameters are one of the resistance factors against Dutch elm disease (Sola et al, 2005).
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