Isolation And Identification Of Salt-tolerant Endophytic Fungi From Oat And Study On Salt Tolerance In Seedling Stage

Soil salinization restricts agricultural production.As a characteristic crop in Inner Mongolia,oat is cultivated in saline-alkali land because of its saline-alkali resistance.In recent years,with the development of green ecological agriculture,the promotion of saline-alkali resistance by endophytic and plant symbiosis is a hot research field.His research with the conventional separation methods,from Inner Mongolia typical bayinnaoer city WuYuan County saline-alkali and current chart the separation of science and technology demonstration garden of oat salt-tolerant significant 19 strains of endophytic fungi as material,through comparing the different endophytic fungi fermentation liquor in 30mmol/L NaCl:Na2SO4=1:1 composite under salt stress in oat seeds seed germination index and 75mmol/L NaCl:Na2SO4=1:1 moderate composite pouring the root of oat seedlings under salt stress the seedling growth of physiological indexes,investigate endophytic fungi of salt tolerance of oats seed germination and seedling growth.The aim is to provide a basis for serious regional crop growth in saline-alkali land.The main conclusions are as follows:1.The endophytic fungus of oat has the function of salt tolerance,and the fermentation broth immersion can effectively alleviate the germination of oat seeds under salt stress,so the fermentation broth of the endophytic fungus can be made into the bacterial agent immersion,so as to improve its adaptation to the abiotic stress,which has important guiding significance for the development and application of in vitro oat endophytic fungus.Under 30mmol/L NaCl:Na2SO4=1:1 combined salt stress,the seed germination rate and germination potential of strains A4L4-8 and C3S1-39 increased by 13.73%and 39.22%?2.63%and 18.42%,respectively,compared with CK.The seed germination index and vigor index of strains BL2S4-20 and CS2L3-51 increased by 16.68%and 24.61%?60.09%and 64.15%,respectively,compared with CK.The radicle length and germ length of strains A4L4-23 and C3S1-39 were 86.95%and 152.93%?28.97%and 23.46%higher than CK,respectively,with significant differences(P<0.05).2.Oat endophytes promoted the growth and dry matter accumulation of oat seedlings under salt stress,protected oat seedlings to maintain the pigment balance in the body,enhanced the photosynthesis of the seedlings,and reduced the loss of water in the seedlings or increased the absorption of water by the roots,thus improving the salt tolerance of oat seedlings.In the pot experiment,under the combined salt stress of 75mmol/L NaCl:Na2SO4=1:1,the fermentation liquid irrigation of 19 endophytic fungi had different effects on the growth of oat seedlings.Among them,strains WSY2-6?D2S2-10?A1R1-11?BL2S4-20?A1R4-24?A1R2-32 could significantly increase the dry and fresh weight of oat seedlings?SPAD value?elative water content of leaves and other morphological and physiological indicators of oat seedlings(P<0.05).3.The endophytic fungi of oat could effectively protect the membrane system of oat seedlings,enhance their tolerance to osmotic stress and their ability to regulate the activity of host plants,so as to improve the salt tolerance of seedlings.The promoting effects of strains D2S2-10,BL2S4-20,A1R4-24,A1R2-32,A1R1-11 and WSY2-6 were obvious.The dry fresh weight of seedlings,the content of free proline,SOD activity and POD activity of root leaves of seedlings were significantly higher than those of CK,and the content of malondialdehyde in root leaves of seedlings were significantly lower than those of CK(P<0.05).4.By analyzing the subordination functions of six seed germination indexes of 19 strains of oat endophytes immersed in fermentation broth under salt stress,the results showed that the order of salinity tolerance of 19 strains of oat endophytes from strong to weak was as follows:BS1S1-50?A4L4-23?A1R1-11?A1R2-41?A4L4-44?BL2R-36?A1R4-24?D2S2-10?A1L1-2?CS1S2-40?15-L-37?A1R2-32?C3S1-39?CS2L3-51?WSY2-6?A4L4-8?G10-1?BL2S4-20.According to the analysis of the subordinate functions of physiological indexes and root morphological indexes of oat seedling under salt stress,the order of salinity tolerance of six strains of oat endophytes was BL2S4-20>D2S2-10?A1R4-24?A1R2-32>A1R1-11>WSY2-6.Based on the comprehensive analysis of the effects of the fermentation broth of endophytic fungi on the germination index and seedling growth physiological index of oats,it can be seen that the strains with strong salt tolerance are BL2S4-20?D2S2-10?A1R4-24?A1R2-32?A1R1-11?WSY2-6.