| Paris Polyphylla is one of rare medicinal plants,and its main medicinal ingredients are polyphyllin(PP)I,II,VI and VII.At present,it mainly relies on artificial cultivation to provide medicinal sources for the market.The use of endophytic bacteria to improve the quality of artificially planted P.Polyphylla is one of current research hotspots.In this study,the growth-promoting characteristics of endophytic bacteria HBR11019,HBR31044,YNR32041 and YNR32046 themselves were analyzed,and the effects of HBR11019 and HBR31044 on the growth and physiological indexes of the potted P.polyphylla were further analyzed,respectively.In addition,the effects of HBR11019 on the growth and physiological indexes of planted P.polyphylla in the field and the contents of PP I,II,VI and VII in the rhizomes were analyzed.These results preliminarily revealed the growth-promoting function and physiological mechanism of endophytic bacteria HBR11019 and HBR31044 on the artificially planted P.polyphylla.The main results were as follows:(1)Analysis of growth-promoting characteristics of four endophytic bacteria themselves showed that HBR11019,HBR31044 and YNR32041 strains except YNR32046 strain could produce alkaline phosphatase(ALP)and acid phosphatase(ACP).Among them,HBR31044 strain had the highest activities of ALP and ACP,whose activities were 210.958 μmol/min/g and 49.853 μmol/min/g,respectively.Except for HBR31044 strain,all of YNR32041,YNR32046 and HBR11019 strain contained inorganic potassium with the content of 2.324 mmol/L,2.277 mmol/L and2.025 mmol/L,respectively.In addition,the four strains contained inorganic phosphorus,gibberellin(GA),indole-3-acetic acid(IAA),ethylene(ETH),abscisic acid(ABA)and zeatin(ZT),and the contents of GA,IAA and ZT in HBR11019 and HBR31044 strains were higher than those in YNR32041 and YNR32046 strains.The results showed that HBR11019 and HBR31044 strains had stronger growth-promoting characteristics than YNR32041 and YNR32046 strains.These results preliminarily revealed the growth-promoting characteristics of HBR11019,HBR31044,YNR32041 and YNR32046 themselves.(2)By analyzing the effects of HBR11019 strain on the growth and physiological indexes of the potted P.polyphylla,it was found that HBR11019 strain had little influence on the growth indexes of the potted P.polyphylla,but had a great influence on the physiological indexes within 30-day detection time range.The main effect on the growth indexes was that the fresh weights of the P.polyphylla seedlings applied with HBR11019 strain were increased by 26.4% compared with the control(P<0.05)on the 10 th day.The main effects of HBR11019 strain on physiological indexes in the rhizomes of the P.polyphylla seedlings compared to the control were as follows: on the 5th day,the contents of soluble protein and ETH were significantly increased by8.2% and decreased by 17.6%,respectively.On the 10 th day,the activities of superoxide dismutase(SOD)and peroxidase(POD)in the rhizomes were significantly increased by 66.4% and 44.0%,respectively.On the 15 th day,the contents of polyphenol oxidase(PPO),GA,ZT and soluble protein in the rhizomes were significantly increased by 7.6%,14.1%,29.0% and 10.2%,respectively.On the 30 th day,the activities or contents of SOD,POD,PPO,GA,ZT,soluble protein and ACC deaminase in the rhizomes were significantly increased by 154.8%,803.1%,16.4%,10.7%,18.9%,9.9% and 17.2%,respectively.Additionally,the effect of HBR11019 strain on the physiological indexes of the stems and leaves of P.polyphylla seedlings was similar to that of the rhizomes.These results preliminarily revealed the growth-promoting function and physiological mechanism of HBR11019 strain on the potted P.polyphylla.(3)By analyzing the effects of HBR31044 strain on the growth and physiological indexes of the potted P.polyphylla,it was found that HBR31044 strain had little influence on the growth indexes of the potted P.polyphylla,but had a great influence on the physiological indexes within the 30-day detection time range.The main effect on growth indexes was that the fresh weight of the P.polyphylla seedlings applied with HBR31044 strain increased by 19.4% compared with the control(P<0.05)on the5 th day.The main effects of HBR31044 strain on the physiological indexes in the rhizomes of the P.polyphylla seedlings compared to the control were as follows: on the 5th day,the activities or content of SOD,GA and soluble protein in the rhizomes increased by 43.4%,14.9% and 68.7%,and the content of malondialdehyde(MDA)and ETH decreased by 37.9% and 14.9%,respectively.On the 10 th day,the activities or contents of POD,ABA and soluble protein in the rhizomes were increased by200.0%,19.4% and 63.2%,respectively,and the MDA content was significantly decreased by 63.8%.On the 15 th day,the activities or contents of POD,GA and soluble protein were significantly increased by 201.9%,18.7% and 42.9%,respectively,and the MDA content was decreased by 66.4%.On the 30 th day,the POD activity and soluble protein content were significantly increased by 197.2% and61.9%,respectively,meanwhile the contents of MDA and ETH were decreased by65.2% and 7.2%,respectively.Additionally,th effect of HBR31044 strain on the physiological indexes of the stems and leaves of P.polyphylla seedlings was similar to that of the rhizomes.These results preliminarily revealed the growth-promoting function and physiological mechanism of HBR31044 strain on the potted P.polyphylla.(4)By analyzing the effects of HBR11019 strain on the growth indexes,physiological indexes and the content of PP in the rhizomes of planting P.polyphylla in the field,it was found that the HBR11019 strain had a great effect on those indexes in the 60-day detection time range.The main effects of HBR11019 strain on the growth indexes of the planting P.polyphylla compared to the control were as follows:on the 15 th day,the plant height was increased by 20.1%(P<0.05).On the 60 th day,the plant height and the rhizome length were increased significantly by 32.1% and9.0%(P<0.05),respectively,meanwhile the fresh weight of rhizomes,stems and leaves were increased significantly by 91.9%,130.8% and 74.2%(P<0.05),respectively.The main effects of HBR11019 strain on the physiological indexes of the rhizomes of the planting P.polyphylla compared to the control were as follows:on the 15 th day,the activities or contents of SOD,PPO,IAA,GA,soluble protein and ETH were significantly increased increased by 47.7%,25.0%,18.6%,26.1%,40.3%and 20.0%,respectively.On the 30 th day,the activities or contents of PPO,GA,soluble protein and ACC deaminase were significantly increased by 34.2%,26.5%,98.7% and 30.2%,respectively,and the ETH content was significantly decreased by24.6% compared with the control.On the 60 th day,the contents of PPO,GA,soluble protein and ACC deaminase were significantly increased by 24.2%,13.0%,80.0%and 28.3%,respectively,and the ETH content was significantly decreased by 13.6%.Additionally,the effect of HBR11019 strain on the physiological indexes of the stems and leaves of the planting P.polyphylla in the field was similar to that of the rhizomes.In addition,the main effects of HBR11019 strain on the contents of PP in the rhizomes were as follows: the PP II and VI contents were significantly increased by117.9% and 169.6% compared with the control on the 15 th day.On the 30 th day,the PP I and VI contents were significantly increased by 34.7% and 128.3%,respectively.These results preliminarily revealed the growth-promoting fucntion and physiological mechanism of HBR11019 strain on the planting P.polyphylla in the field. |
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