Studies On Piriformospora Indica To Salt Resistance Response Mechanism Of Lolium Perenne

Lolium perenne,as a Cool-season turfgrasses.It is the preferred grass species for greening on light saline alkali soil.Lolium perenne has many advantages,including multiple tillering,barren soil resistance,developed root systems,disease resistance,resistance to trampling,ability to quickly form lawns,low planting costs,rapid growth,high quality and yield,rich nutrition,good palatability,and high economic value.It was not only an ideal plant material for winter landscaping,but also one of the preferred forage grasses for animal husbandry in China.It has the bright market prospect.In this study,Lolium perenne and Piriformospora indica are used as experimental materials.Through seedling cultivation,inoculation,and cultivation in the laboratory.Salt stress pot trials in the greenhouse for 8 weeks with 0 m M,50 m M,150 m M,and250 m M salt stress concentrations.By these two methods,comprehensively study the characteristics and changes in growth,physiology,photosynthesis and other indicators of Lolium perenne inoculated with Piriformospora indica.Explore the response mechanism of vaccination with Piriformospora indica to the salt tolerance of Lolium perenne.Provide theoretical basis and technical support for the promotion of Lolium perenne in saline alkali areas.The main research conclusions are as follows:（1）Piriformospora indica had successfully colonized Lolium perenne.By microscopic examination of the roots of Lolium perenne inoculated with 4 salt concentrations.It was found that the spores and hyphae of Lolium perenne were clearly observed in the middle of the plant root,and they are densely distributed.The infection rates were 40.0%,33.3%,25.0%,and 8.3%.Therefore,it indicates that a symbiotic relationship had established between Lolium perenne and Piriformospora indica.（2）Piriformospora indica significantly promoted the growth of Lolium perenne under salt stress.After inoculation with Piriformospora indica,the total dry weight increased by 52.4%,42.1%,34.9%,and 12.1%under the four salt stress treatments,and there were significant differences between each treatment.At a concentration of 0m M,the plant height growth,height growth rate,aboveground fresh weight,aboveground dry weight,underground fresh weight,and underground dry weight of Lolium perenne had increased 41.6%,45.3%,18.9%,54.2%,45.7%and 43.9%in the inoculation group compared to the control group.The research results indicate that Piriformospora indica had a significant promoting effect on the growth of Lolium perenne under salt stress.（3）Piriformospora indica had enhanced Lolium perenne photosynthesis to resist salt damage.Net photosynthetic rate,water used efficiency of Lolium perenne inoculated with Piriformospora indica at 150 m M and 250 m M salt stress concentrations were significantly higher in the inoculated group than the control group by 43.4%,49.2%,28.7%and 58.7%.Intercellular CO₂ concentration of Lolium perenne is significantly lower in the inoculated group than in the control group,decreasing by 10.1%and 18.2%.The results showed that Piriformospora indica could improve the net photosynthetic rate,water utilization,reduce the intercellular CO₂ concentration,alleviate the salt damage of the plants and promote the growth of Lolium perenne with salt stress.（4）Piriformospora indica was able to significantly reduce the soluble protein content of Lolium perenne during salt stress.The soluble protein content of Lolium perenne increased gradually with increasing salt concentration,and the inoculated group was always lower than the control group.At 4 salt concentrations,the soluble protein content of the inoculated group was 11.7%,9.5%,3.8%,and 8.1%lower than that of the control group,respectively.（5）Piriformospora indica was able to significantly reduced the content of malondialdehyde produced by Lolium perenne during salt stress.Through correlation analysis,it was found that there were different level of significant negative correlations between malondialdehyde and growth indexes of inoculated Lolium perenne while the difference was not significant for the control.At 0 m M,50 m M,and 250 m M salt concentrations,malondialdehyde content in Lolium perenne leaves was reduced by 32.6%,32.5%,and 1.3%in the inoculated group compared to the control group.The results indicate that inoculation with Piriformospora indica could reduce the malondialdehyde content of Lolium perenne during salt stress as a way to alleviate the damage caused to cell membrane permeability（6）Pirifompora indica increased the superoxide dismutase activity of Lolium perenne under salt stress.At salt concentrations of 0 m M,50 m M,150 m M,and 250 m M,the SOD of the inoculation group was higher than that of the control group,with an increase of 25.1%,53.4%,64.7%,and 11.5%.Especially at 50 m M,the inoculation group was significantly larger than the control group.The results showed that inoculation with Piriformospora indica could increase the SOD and enhance the salt tolerance under salt stress.The results of the combined Pearson Correlation Analysis and Two-factor ANOVA showed that inoculation with Piriformospora indica increased the growth of Lolium perenne and promoted its salt tolerance mainly by increasing the net photosynthetic rate as well as reducing the malondialdehyde content.