The Initial Research On Effects Of Saline-alkali Stress On Physiology And Metabolism Of Puccinellia Tenuiflora-arbuscular Mycorrhizal Symbiosis

Puccinellia tenuiflora is a perennial herb of the genus Pleurotus.It is one of the preferred pastures selected from more than 140 salt-tolerant alkaline pastures in China after nearly 20 years of scientific experiments.AM fungi can improve the salt and alkali resistance of plants.Through previous studies,we found that the symbiotic ability of Puccinellia tenuiflora and AM fungi is strong,and we have identified Funneliformis mosseae and Rhizophagus intraradices.The two AM fungi are the dominant AM fungal species in the grass roots.In this study,Puccinellia tenuiflora was used as plant material to inoculate the above two dominant AM fungi,and the effects of these two fungi on the physiological mechanism of Puccinellia tenuiflora under NaCl and NaHCO3 stress were discussed.On this basis,the changes of the content of metabolites of Puccinellia tenuiflora inoculate with Rhizophagus intraradices under NaHCO3 stress were further investigated.Through the above physiological indicators and the changes of metabolite content,it provides a scientific basis for improving and restoring degraded Songnen saline-alkali grassland.It can also be used to screen genes related to salt and alkali stress,and then use genetic techniques and methods to further study the function of these genes.The mean research results are as follows:1.After inoculation of two dominant AM fungi,the activity of antioxidant enzymes in the grass was significantly enhanced,and the activity of sucrose synthase(SS)in the host was also significantly improved,which was beneficial to the accumulation of sucrose accumulation in the host;The content of free amino acid increase can further enhance the osmotic adjustment ability of Puccinellia tenuiflora cells to maintain normal cell structure and function to alleviate the harm caused by saline-alkali stress.The above physiological indexes almost reached the maximum value under the stress of 200mmol·L-1,and when the treatment concentration exceeded the value,the salt-tolerance ability of Puccinellia tenuiflora began to decrease,indicating that 200mmol·L-1 may be the critical concentration of salt-alkali stress.2.Both of the dominant AM fungi can significantly increase the accumulation of various antioxidants in the Puccinellia tenuiflora,not only enhance the antioxidant enzyme activity and the ability of enzymatic reaction,but also increase the accumulation of antioxidants.As with the above,all the indicators showed a peak at 200mmol·L-1 stress,and the increase of the antioxidant content of Puccinellia tenuiflora in Rhizophagus intraradices was higher than that of the Puccinellia tenuiflora inoculate with Funneliformis osseae.,and the inhibition of NaHCO3 stress is stronger than NaCl stress.3.The critical concentration of 200mmol·L-1 was selected as the treatment concentration of the study,and Rhizophagus intraradices with obvious dominant degree in the above two AM fungi was inoculated as the microbial agent.The results showed that under the stress of NaHCO3,the strain could significantly increase the content of amino acids and amines,carbohydrates and polyols,as well as inorganic acids and organic acids,and hydromorphone was most up-regulated.21.38 times,the obvious changes of the above metabolites participate in the cycle of TCA,the synthesis of ATP required for nitrogen metabolism and the maintenance of cell osmotic balance,and it is possible to indirectly induce the alkali resistance of Puccinellia tenuiflora under alkali stress.