Effects Of Arbuscular Mycorrhizal Fungi On The Growth Of Suaeda Glauca In The Soil From Saline-Alkaline Wetlands

As the largest wetland in the same latitude of the earth, Wuliangsuhai wetland ecosystem plays an important role in maintaining the ecological balance of the surrounding area. However, sustainable development and utilization of wetlandresourceshave caused worsening salinization of Wuliangsuhailakeside zone. Therefore, it is urgent to seek a feasible way to comprehensively control saline-alkaline wetlands from the long-term overall situation for the protection oflocal environmentand the maintenance of the wetland ecosystem stability. Biological measures areconsidered as one of the most cost-effective ways to restorethe saline-alkaline wetlands. In this study, a typicalhalophyte,suaeda glauca bunge, was selected as test plant and soil collected from Wuliangsuhai wetlands was selected as growth substrates. A greenhouse pot experiment was conducted to investigate the influence of different arbuscular mycorrhizal (AM) fungi (F. mosseae> R. irregularis^ G. tortuous、 G. aggregatum、 F. coronatum、 C. etunicatumand C. lamellosum) on the plant growth, salt ions uptake, rhizosphere soil pH as well as glomalin-related soil protein content of suaeda glauca grown in the soil from saline-alkaline wetlands.Simultaneously,the physiology and biochemistry indexes of plants were analyzed to explore the mechanisms of AM fungi. The roles of AM fungi-halophyte combinations played in the restoration of saline-alkaline wetlands were investigated and the feasibility of the combination was also explored. The aim was to provide scientific basis and technical support for the restoration of saline-alkaline lake wetland ecosystem in arid area. The main results were as follows:(1) In thesoil from saline-alkaline wetlands, a symbiotic relationship was successfully established between each AM fungi andsuaeda glauca.The average mycorrhizal infection rates wereranging from 6%to 10%. There was no significant difference amongsevenAM fungi species.(2) In thesoil from saline-alkaline wetlands, inoculation with F mosseae, R. irregularis and G. tortuous significantly promoted the growth ofsuaeda glauca, and the total dry weightsof inoculated suaeda glauca were increased by 47%,29%and 74%, respectively.(3) Inoculation with G. tortuous had the most significant effect in promoting the absorption of nitrogen, phosphorus, potassium, calcium and magnesium in the shoots ofsuaeda glauca and nitrogen in the roots,which were increased by 204%,77%,35%, 84%,70%and 146%, respectively. Inoculation with R. irregularis significantly promoted the absorption of phosphorus, potassium, calcium and magnesium in the roots,which were increased by 45%,133%,75%and 100%, respectively.(4) Inoculation withhF. mosseae, R. irregularis, G. tortuous, G. aggregatum and F. coronatum promoted the absorption of Na+and Cl’in shoots and roots ofsuaeda glaucato varying degrees, showing an increasing tendency. Particularly,inoculation withG. tortuous significantly increased the absorption of Na+inthe shoots and roots and Cl’in the roots by 135%,106%and 77%, respectively。(5) Inoculation with F. mosseae, G. tortuous, F. coronatum and C. lamellosumincreasedthe soluble protein contentsin the leaves of suaeda glauca by 49%,42%,35%,23%, respectively.Inoculation with F. mosseae and G. tortuous also increasedthe soluble sugar and proline contentsinthe leaves by 26%,8%and 39%, 24%, respectively. Inoculation with R. irregularisincreasedthe proline contentsin leavesby 73%.(6) All AM fungi inoculation improved the catalase activity in the leaves of suaeda glauca by 12%-81%.The activity of superoxide dismutase was increased by F. mosseae, R. irregularis and G. aggregatum. All inoculationsexcept for R. irregularis and C. lamellosum, increased the peroxidase activity in the leaves. Inoculation with R. irregularis, G. tortuous, G. aggregatum, C. etunicatum and C. lamellosumdecreased the malondialdehyde contentsin the leaves.(7) All the AM fungi inoculations decreasedrhizosphere soil pH,and G. aggregatum, C. etunicatum and C. lamellosumhad a significant effect on the changes of soil pH. All AM fungi inoculationsexcept forF. mosseaesignificantly increased the total glomalin-related soil protein contents of rhizosphere soil by 6%-42%.The results demonstrated that AM fungi can increase the saline-alkaline tolerance of suaeda glauca and the sevenAM fungi species haddifferent impact on the growth of suaeda glaucain the soil fromsaline-alkaline wetlands, indicating that the differences of ecological functions of different AM fungi. Among the seven AM fungi species, G. tortuous significantly promoted the growth of suaeda glauca and the absorption of Na+and Cl- from soil andhad a potential role in improvingthe restoration efficiency of saline-alkaline wetlandsby halophytes. AM fungi-halophytes combinations have certain application prospect to restoresaline-alkaline wetlands.However, due to the low infection rateof AM fungi in saline-alkaline environments, AM fungi which are better adaptable to saline-alkaline and excellent halophyte species should be screened in the field tests to optimize the AM fungi-halophytes combinations and to explore the practical effects of AM fungi on the bioremediation of saline-alkaline wetlands under field conditions.