title: [Effects of arbuscular mycorrhizal fungus on the seedling growth of grafted watermelon and the defensive enzyme activities in the seedling roots].
abstract: A greenhouse pot experiment was conducted to study the effects of arbuscular mycorrhizal fungus Glomus versiforme on the seedling growth and root membrane permeability, malondiadehyde (MDA) content, and defensive enzyme activities of non-grafted and grafted watermelon growing on the continuously cropped soil. Inoculation with G. versiforme increased the seedling biomass and root activity significantly, and decreased the root membrane permeability and MDA content. The seedling shoot fresh mass, shoot dry mass, and root activity of non-grafted watermelon increased by 57.6%, 60.0% and 142.1%, and those of grafted watermelon increased by 26.7%, 28.0% and 11.0%, respectively, compared with no G. versiforme inoculation. The root membrane permeability of non-grafted seedlings (C), grafted seedlings (G), non-grafted seedlings inoculated with G. versiforme (C+M), and grafted seedlings inoculated with G. versiforme (G+M) was in the order of C >G>C+M>G+M, and the root MDA content was in the sequence of C>G>G+M>C+M. G. versiforme inoculation increased the root phenylalanine ammonialyase (PAL), catalase (CAT), peroxidase (POD), beta-1,3-glucanase and chitinase activities of grafted and non-grafted seedlings significantly, and the peaks of the POD, PAL and beta-1,3-glucanase activities in the mycorrhizal roots appeared about two weeks earlier than those in the non-inoculated roots. These results indicated that inoculating arbuscular mycorrhizal fungus G. versiforme could activate the defensive enzyme activities of non-grafted and grafted watermelon seedlings, enable the seedling roots to produce rapid response to adversity, and thus, improve the capability of watermelon seedling against continuous cropping obstacle.
authors.affiliation: Institute of Mycorrhizal Biotechnology, Qingdao Agricultural University, Qingdao 266109, Shandong, China. chenke_531@163.com
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.forename: Ji-Qing
authors.initials: JQ
authors.lastname: Sun
authors.forename: Run-Jin
authors.initials: RJ
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Li
mesh_terms: D000383:Agriculture / Q000379:methods*; D002374:Catalase / Q000378:metabolism; D029773:Citrullus / Q000254:growth & development* / Q000382:microbiology; D038821:Mycorrhizae / Q000502:physiology*; D009195:Peroxidase / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000382:microbiology; D036226:Seedlings / Q000254:growth & development* / Q000382:microbiology
chemical_list: D002374:Catalase; D009195:Peroxidase