Effects Of Endophyte Infection On Salt Tolerance Of Wild Barely (Hordeum Brevisubulatum)

Wild barley(Hordeum brevisubulatum),a perennial elite forage grass growing at native grassland at Linze county in Gansu province of China,symbiotic with Neotyphodium endophyte was studied,mainly including endophyte detection,effects of endophyte on seed germination,physiological,vegetative and reproductive growth in pot and field experiments under salt stress conditions.The results summarized as followings:1.Endophyte infection rate was ranged from 76%to 100%(average 91%) among the 13 wild barley populations grown at provinces of gansu,Xingjiang and Inner Mongolia.2.Salt tolerance of seedling was assessed by the germination rate,coleoptile length and root length in a seedling grown in 0-400 mmol/L NaCl solution.The germination rate, coleoptile and root length of Neotyphodium infected plants(E+) were much higher than that of un-infected plants(E-) when NaCl concentration reached 200,300 mmol/L (p＜0.05).3.In the pot experiment,growth and physiological characters of E+ and E- wild barley were investigated under 0-300 mmol/L NaCl.The results showed that compared to E- plants,the tiller number,biomass accumulation,contents of soluble sugar and proline, activite of SOD isozyme of E+ plants were significantly increased(p＜0.05),respectively. However,malondialdehyde content was significantly decreased(p＞0.05).4.In a field experiment,vegetative and reproductive growth characters of E+ and E-wild barley were investigated under high salt(3%) and low salt(0.03%) treatment.It was found that relative tillering rate and the ration of reproductive tillers of E+ plants were approximated 41.56%and 116.5%greater than E- plants only under high salt stress condition,respectively.E+ plants had significantly more dry matter of shoot than E- plants under high salt treatment(p＜0.05).E+ plants had 43.94%more ripen inflorescences per plant than E- plants under high salt treatment,but there were no significant differences between E+ and E- plants were detected under low salt treatment(p＞0.05).The lengths of ripen inflorescences of E+ plants were 18.67%and 18.18%longer than that of E- plants under high and low salt stress,respectively.E+ plants showed a greater seed numbers per inflorescence and seed yield per plant under both stress conditions,but a significant more seed numbers and yield under high salt stress(p＜0.05).No differences in dry matter weight of vegetative tillers per plant and 1000-seed-weight of seeds were found between E+ and E- plants under two salt treatments(p＞0.05).