A Study On The Symbiotic Effect Of Glomus Mosseae And Cucumber

Arbuscular Mycorrhizal Fungi(AM fungi)are widely distributed in agroecosystem.After AM fungi infects the roots of host,they can form symbiosis.The mycorrhizal effect is influenced by many factors such as AMF,host and growth medium.The reciprocal symbiont is beneficial to the host growth and the improvement in stress resistance.Cucumber is one of the main vegetables in protected conditions in China,and the cultivation area is increasing year by year.As we know cucumber seedlings'qualities is closely related to quantities and fruits qualities.AMF and cucumber roots can form mycorrhizal symbiosis,but AMF and host plants have the characteristics of mutual selection.In view of the phenomena,pots experiments were conducted to explore the mycorrhizal effect and mechanisms involved in,in the study,the cucumber seedlings were inoculated with AM fungus at the nursery stage.It is necessary to provide theoretical basis and to applicate the fungus resources for Protected cucumber cultivation.Some conclusions are obtained from the research as follows.(1)When the sterilized vermiculite was selected as the nursery substrate,Glomus mosseae and two cucumber varieties(‘Chiyu 126'and‘Jinyan 4')can form mycorrhizal associations,but the mycorrhizal effect is significantly different.Compared with the control the dry weight of shoots and roots was increased by 45.5%and 30.6%respectively for‘Chiyu126'inoculated with G.mosseae,meanwhile,the total nitrogen and phosphorus concentration in shoots were 1.29 times and 1.39 times as much as the controls respectively and the nitrogen and phosphorus nutrition level was significantly improved,however,the root growth of‘Jinyan No.4'was significantly inhibited by inoculating with G.mosseae and total biomass and the total nitrogen concentration in shoots were significantly lower than those of its corresponding control.(2)When the sterilized vermiculite was selected as the nursery substrate,'Jinyan4'was inoculated with G.mosseae at nursery stage.Sampling was only taken on the seedling stage,the mycorrhizal infection rate was only 26.5%,meanwhile,the seedling index decreased after inoculation with G.mosseae.The results proved that the association relationship between the symbionts was weak.(3)When the sterilized vermiculite was selected as the nursery substrate,'Jinyan4'was inoculated with G.mosseae at nursery stage.Samplings were taken continuously during the seedling stage.Before the 3^rdweek the root is the growth center and a low nutrition concentration(?25%)is beneficial to form mutual relationship.But the beneficial mycorrhizal effects disappeared with the increase of nutrition concentration,and we found that the mycorrhizal seedlings growth was weaker than that of the control.(4)When the soil from the continuous cropping system was selected as the nursery substrate,soil sterilization and G.mosseae have a synergistic effect on“Jinchun 3”.Seedlings inoculated with G.mosseae on sterilized soil grow best among all the treatments.For the soil sterilization,the mycorrhizal effect was 31.4%and nitrogen,phosphorus and potassium concentration in shoot of mycorrhizal seedlings were 1.18,1.33 and 1.31 times than those of nonmycorrhizal seedlings respectively,and the mycorrhizal contribution was more than 40%.