Effects Of Mixed Inoculation Of AMF And Rhizobia On The Alkali Tolerance Of Alfalfa

Alfalfa(Medicago sativa L.)is an alias purple alfalfa,which is mainly distributed in the northern part of China and the Yangtze river valley.Due to its high nutritional value,it has become one of the most widely cultivated herbage varieties in the world.Land salinization and other problems exist in many regions of China.At the same time,the improper use of pesticides and fertilizers greatly reduces the land fertility,affect the quality of alfalfa,thus speeding up the research of bio-bacterial manure.Arbuscular mycorrhizal fungi(AMF)and rhizobia are common symbiotic bacteria in soil,which can coexist with alfalfa and other leguminous vegetation.AMF and rhizobia can survive alone in alfalfa root,but also work together to form two bacteria a host of triple symbiotic system.The two strains can promote the absorption of nutrients such as nitrogen and phosphorus in arid soil,increase soil nutrients and improve soil quality,therefore the growth of host plants can be improved.Meanwhile,the nutrients produced by the growth of the plant ensure the normal growth and reproduction of the bacteria,maintain the stability of the biological community in the soil.The reciprocal growth model in nature will provide a reference for global agriculture sustainable development.There were many studies on the plant growth status and resistance of single inoculated AMF or rhizobia,but the mixed inoculation of rhizobium and AMF was less related to the alkalinity of leguminous plants.This study leguminous plant alfalfa Long Mu 806 as a material,respectively set by the fungus(NI),single inoculation of arbuscular mycorrhizal fungi BGC XJ08 A balloon mold(Glomus mosseae)(AI),the single inoculation of alfalfa rhizobia CCBAU 81024(RI),mixed inoculation of AMF and rhizobia(MI)four processing.Through the investigation of alfalfa root and leaf growth and physiological indicators,and the determine of the difference between single and mixed inoculated to improve the alkali resistance of alfalfa under the condition of normal growth and the process of alkali stress,theoretical basis for the development of mixed bacteria preparation can be provided.The results are as follows:1.Under normal conditions,the growth of single inoculated AMF,single inoculated Rhizobium and mixed inoculated AMF-Rhizobium were higher than that of uninfected plants.The chlorophyll content of single inoculated Rhizobium and mixed AMF-Rhizobium was higher,and the root length and plant height of single grafting AMF and mixed AMF-Rhizobium were relatively large,and the number of branches grew more denser.2.After alkali stress treatment,the growth of each plant was inhibited,but the single inoculation of AMF,single inoculated Rhizobium and AMF-Rhizobium increased the alkaline resistance of alfalfa to different degrees.Compared with unplanted plants,the MDA content and relative conductivity of AI,RI and MI remained low,the relative water content of cells was larger,the damage degree of cell membrane was lower,the content of proline and soluble sugar was higher,and the activity of SOD,POD and CAT was higher.Above all index analysis,osmotic adjustment ability and antioxidant capacity of plants can be improved by single inoculation and mixed inoculation,and the effect of mixed inoculation is even better.Therefore,it is concluded that the mixed inoculation of arbuscular mycorrhizal fungi BGC XJ08A(Glomus mosseae)and alfalfa Rhizobium(CCBAU 81024)can effectively improve the growth and alkali resistance of alfalfa.