Influences of Natural Fibrous Root Decay on Growth and Active Component Content of Paris polyphylla var. yunnanensis / 中国实验方剂学杂志

Objective:To explore the effect of natural decay of exogenously added fibrous roots on the growth and development of <italic>Paris polyphylla</italic> var. <italic>yunnanensis </italic>and its medicinal quality. Method:The effects of natural decay of fibrous roots at different amounts on mycorrhizal infection rate， physiological and biochemical indexes， and saponin contents of <italic>P. polyphylla</italic> var. <italic>yunnanensis </italic>were studied in pot culture experiments at room temperature. Result:The results showed that the infection rate of arbuscular mycorrhizal （AM） fungi in the root of <italic>P. polyphylla</italic> var. <italic>yunnanensis </italic>was not significantly affected by different fibrous root treatments， but there were significant differences in infection intensity. The photosynthetic pigment content in the leaves declined significantly with the increase in fibrous root amount， and the total chlorophyll was decreased by 78.7% at most. The contents of soluble protein， soluble sugar and malondialdehyde in the leaves of <italic>P. polyphylla</italic> var. <italic>yunnanensis </italic>showed an overall upward trend. The activities of the three protective enzymes varied. The peroxidase and malondialdehyde were reduced by 181.6% and 200.0% at most. In the root system of <italic>P. polyphylla </italic>var. <italic>yunnanensis</italic>， the contents of the above-mentioned six components decreased to varying degrees， with the largest reductions of peroxidase and malondialdehyde reaching 44.6% and 69.7%. Different fibrous root treatments resulted in a decrease in active component content of <italic>P. polyphylla </italic>var. <italic>yunnanensis</italic>. The total content of the four saponins was decreased by 58.9% at most， and the total saponin content by 46.9%. Conclusion:The natural decay of fibrous roots affects the soil microbial environment of root system， reduces the photosynthetic pigment content in leaves， and destroys the stability of cells， thus interfering with the growth and development of <italic>P. polyphylla </italic>var. <italic>yunnanensis</italic>， reducing its medicinal components， and causing continuous cropping obstacles.

Screening and identification of potassium-dissolving bacteria from different rhizosphere soil of Paris polyphylla var. yunnanensis / 中国中药杂志

The study aiming at exploring the potassium-dissolving capacity of rhizosphere potassium-dissolving bacteria from diffe-rent sources and screen the strains with high potassium-dissolving ability, so as to lay a theoretical foundation for cultivation and quality improvement of Paris polyphylla var. yunnanensis sources. The rhizosphere soil of 10 wild and transplanted species from Yunnan, Sichuan and Guizhou provinces was used as the research object. Potassium-dissolving bacteria were isolated and purified, and their potassium-dissolving capacity was determined by flame spectrophotometry, and identified by physiological, biochemical and molecular biological methods. Twenty-six potassium-dissolving bacteria were purified and 13 were obtained from wild and transplanted strains respectively. It was found through the determination of potassium-dissolving capacity that the potassium-dissolving capacity of 26 strains was significantly different, and the mass concentration of K~+ in the fermentation broth were 1.04-2.75 mg·L~(-1), the mcentration of potassium were 0.01-1.82 mg·L~(-1). The strains were identified as Bacillus, Agrobacterium rhizome and Staphylococcus by physiological, biochemical and 16 S rDNA molecular methods, among them Bacillus amylolyticus(4 strains) was the dominant bacterium of Bacillus. The physiology and biochemistry of rhizosphere potassium-dissolving bacteria in P. polyphylla var. yunnanensis rhizosphere were diffe-rent, and the living environment were different, so the potassium-dissolving capacity also changed. Strain Y4-1 with the highest potassium decomposability was Bacillus amylolytic with a potassium increase of 1.82 mg·L~(-1). The potassium-dissolving ability and the distribution of potassium-dissolving bacteria were different in various habitats. The screening of potassium-dissolving bacteria provided a new strain for the preparation of microbial fertilizer. It is expected that B. amyloidococcus Y4-1 can be used as an ideal strain to cultivate mycorrhizal seedlings of P. polyphylla var. yunnanensis.

Isolation and identification of phosphatolytic bacteria in Paris polyphylla var. yunnanensis / 中国中药杂志

The wild resources of Paris polyphylla var. yunnanensis, a secondary endangered medicinal plant, are severely scarce. Introduction and cultivation can alleviate market demand. To screen phosphatolytic bacteria in the rhizosphere soil of P. polyphylla var. yunnanensis and provide data support for the development of high-efficiency microbial fertilizer, in this study, the dilution plate coating method was used to isolate and screen the phosphorus solubilizing bacteria with the ability of mineralizing organic phosphorus from the rhizosphere soil of wild and transplanted varieties of P. polyphylla var. yunnanensis in 10 different locations in Yunnan, Sichuan and Guizhou. After separation and purification, the phosphatolytic capacity was analyzed by qualitative and quantitative analysis. Combined with physiological and biochemical experiments, the strains were identified using 16 S rDNA sequencing analysis. Forty one strains were selected from the rhizosphere soil of P. polyphylla var. yunnanensis from 10 different habitats. Among them, 21 strains were obtained from the rhizosphere soil of the wild variety P. polyphylla var. yunnanensis and 20 strains were obtained from the rhizosphere soil of the transplanted variety. And significance analysis found that 41 organophosphate solubilizing strains had significant differences in their ability to solubilize phosphorus. The amount of phosphate solubilizing was 0.08-67.61 mg·L~(-1), the pH value was between 4.27 and 6.82. The phosphatolytic amount of strain Y3-5 was 67.61 mg·L~(-1), and the phosphorus increase amount was 57.57 mg·L~(-1). All 41 strains were identified as Gram-positive Bacillus. Combining physiological characteristic and phylogenetic trees, Bacillus mobilis Y3-5 was finally selected as the candidate rhizosphere phosphatolytic bacteria of P. polyphylla var. yunnanensis. The distribution of phosphorus solubilizing bacteria in the rhizosphere soil of P. polyphylla var. yunnanensis was different, and there were significant diffe-rences in phosphorus solubility. Organophosphate-dissolving strain Y3-5 is expected to be a candidate strain of P. polyphylla var. yunnanensis microbial fertilizer.