tailieunhanh - Báo cáo lâm nghiệp: " Cytokinin activity in Citrus seedlings colonized by mycorrhizal fungi"

Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Cytokinin activity in Citrus seedlings colonized by mycorrhizal fungi. | 734s Ann. Sci. For. 1989 46 suppl. 734s-736s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA Cytokinin activity in Citrus seedlings colonized by mycorrhizal fungi . Dixon School of Forestry Auburn University Auburn AL 36849 . Introduction The level of cytokinin-like substances is greater in the leaves of the vesicu-lar-arbuscular mycorrhizal monocotyledon Bouteloua gracilis compared to non-mycorrhizal plants Allen et al. 1980 . This increase may be associated with colonization of roots by vesicular-arbus-cular mycorrhizal fungi or the result of improved mineral nutrition Van Staden and Davey 1979 . The objectives of this research were to 1 establish the presence of cytokinins in leaves of Citrus jambhiri Lush seedlings inoculated with vesicular-arbuscular mycorrhizal fungi and 2 isolate cytokinins with demonstrated biological activity. Materials and Methods Five vesicular-arbuscular mycorrhizal fungi including Glomus caledonium Nicol and Gerd. Gepigaeum Dan and Trappe G etu-nicatum Becker and Gerd. G. fasciculatum Thaxt. Gerd and Trappe and G. mosseae Nichol and Gerd. were used to inoculate seedlings using methods described by Bethen-falvay and Yoder 1981 Plants were grown in a glasshouse for 105 d under previously described culture conditions Menge etal. 1978 . Following harvest seedling dry weight and vesicular-arbuscular mycorrhizal colonization of inoculated and non-inoculated plants were measured. Seedling leaf subsamples were analyzed for phosphorus content Menge et al. 1978 . Leaf samples were collected for cytokinin analysis before final harvest of seedlings. The partially purified cytokinin extracts of fully expanded leaves were separated by high performance liquid chromatography using procedures described by Horgan and Kramers 1979 . Results All c. jambhiri seedlings inoculated with fungal symbionts exhibited abundant vesi-cular-arbuscular mycorrhizal development after 105 d. Control seedlings were non-mycorrhizal. Inoculation of Citrus