The Diversity Of Endophyte Isolated From Malaxis Microtatantha And Its Growth Promoting Characteristics

Malaxis microtatantha is a newly discovered orchid of marsh orchid family.Its growth environment is strict rock conditions.In this experiment,57 strains of endophytic bacteria were isolated from the Malaxis microtatantha by using LB culture medium,DN culture medium and NFB culture medium.Through IS-Fingerprint clustering and physiological and biochemical experiments,the endophytic bacteria of the Malaxis microtatantha were clustered into 15 groups,including Klebsiella pneumoniae subsp.Ozaenae,Paenalcaligens,Paenalcaligens suwonensis,Serratia marcescens subsp.marcescens 、 Providencia vermicola 、 Phytobacter diazotrophicus 、 Providencia rettgeri、Proteus terrae、Proteus mirabilis、Bacillus zhangzhouensis、Bacillus altitudinis、Pseudomonas geniculata 、 Bacillus velezensis 、 Klebsiella quasipneumoniae subsp.quasipneumoniae 、 Bacillus Megaterium,which reflects the species diversity of endophytic bacteria in the plant.The activity of nitrogenase was measured by acetylene reduction method in 15 representative strains.The results showed that 5 strains had nitrogenase activity,and the activity of nitrogenase was in the range of 192.63-497.40 nmol /(m L·h)Among them.Twelve strains have the ability to secrete auxin,the ability to produce auxin is in the range of 9.22-31.31 mg/L,and the representative strain XN50 of group XIII has the highest ability to produce auxin,31.31mg/L Among them.Six strains have the ability to dissolve phosphorus,and the ability to dissolve phosphorus is in the range of 9.10-38.93mg/L In the range of among them,XD28 the representative strain of group X has the highest potassium resolving ability,which is 38.93 mg/L.Eight strains have the ability to resolve potassium,which is in the range of 23.56-51.34 mg/L,and XL10,the representative strain of group IV,has the highest potassium resolving ability,which is 51.34 mg/L.Eleven strains have the ability to secrete iron carriers.It can be seen that there are differences in the functions of 15 representative strains of endophytic flora of Malaxis microtatanthas,and those strains with the same function might have differences in the ability,indicating the diversity of the endophytic bacteria function of Malaxis microtatanthas.The physiological and biochemical characteristics and growth promoting characteristics of 15 groups were analyzed.The representative strains XL1 the representative strain of group,XL11 the representative strain of group V,XL15 the representative strain of group VI and XN51 the representative strain of group XIV were selected for pot experiment.The results showed that Klebsiella pneumoniae subsp.Ozaenae and Phytocharacter were better than those of the control group diazotrophicus has the ability of dissolving phosphorus,dissolving potassium,producing iron carrier,producing long eleent and fixing nitrogen.It is a comprehensive strain with comprehensive functions.It can be used as the potential resource of bio fertilizer and growth promoting bacteria in the orchid family,and provides a new resource for bio fertilizer of the orchid family.The results showed that XL15 and xl11 had significant effect on the growth of rape.Among them,strain XL15 increased plant height by 20.51%,rhizome diameter by 23.00%,fresh weight by 45.41% and dry weight by 49.54%;strain xl11 increased plant height by 19.43%,rhizome diameter by 18.2%,fresh weight by 35.06% and dry weight by 41.07%.The effect of endophytic bacteria on rape growth was XL15 > XL11 > XN51 > XL1.Therefore,XL15 and XL11 can be considered as potential growth promoting strains.