Open Access

ARTICLE

Effect of Nitrogen-Fixing Bacteria on Rhizosphere Nitrogen Forms and Bulb Medicinal Components of Fritillaria taipaiensis P. Y. Li

Zhenyu Liu¹, Panpan Wang¹, Yanjing Liu¹, Mingyan Ye^1,2, You Zhou¹, Dongqin Guo^3,*, Nong Zhou^1,*
1 College of Chongqing of Biology and Food Engineering, Chongqing Sanxia University of Science and Technology, Chongqing, China
2 College of Agriculture and Forestry Science and Technology, Chongqing Three Gorges Vocational College, Chongqing, China
3 School of Pharmacy, Chongqing Three Gorges Medical College, Chongqing, China
* Corresponding Author: Dongqin Guo. Email: ; Nong Zhou. Email:

Phyton-International Journal of Experimental Botany https://doi.org/10.32604/phyton.2026.084016

Received 15 April 2026; Accepted 15 July 2026; Published online 03 August 2026

Abstract

Purpose: This study aimed to investigate the effects of nitrogen-fixing bacteria (NFB) on the nitrogen forms in rhizosphere soil and the biomass and medicinal components in the bulbs of Fritillaria taipaiensis. Methods: Three NFB strains were isolated and inoculated into the rhizosphere of F. taipaiensis through a pot experiment. Eight treatment groups were established: control (CK), Rahnella aquatilis (N1), Pseudomonas chlororaphis (N2), Paenibacillus stellifer (N3), R. aquatilis + P. chlororaphis (N4), R. aquatilis + P. stellifer (N5), P. chlororaphis + P. stellifer (N6), and R. aquatilis + P. chlororaphis + P. stellifer (N7). After 8 months of inoculation, the contents of different nitrogen forms in rhizosphere soil and peimine, peiminine, peimisine, sipeimine, and sipeimine glycosides in bulbs were measured. The variations in medicinal components and nitrogen forms were analyzed, and the correlations between bulb alkaloids and nitrogen forms were investigated through principal component and correlation analyses. Results: The contents of ammonium nitrogen, nitrate nitrogen, and amide nitrogen significantly increased in the rhizosphere in seven treatment groups compared with the CK group. The bulb biomass increased to varying degrees under all treatments, with the most pronounced effects observed in the N5 group. Similarly, the total alkaloid content in the bulbs was significantly enhanced by NFB inoculation. The total alkaloid content in the bulbs increased by 22.92%, 40.45%, 43.42%, 58.51%, 61.36%, 46.47%, and 54.42%, respectively, in the seven treatment groups compared with the CK group. Principal component analysis indicated that the combination of R. aquatilis and P. stellifer exhibited the strongest enhancement effect on alkaloid content. Correlation analysis revealed that the content of ammonium nitrogen was negatively correlated with the content of nitrate nitrogen but positively correlated with amide nitrogen content, fresh weight, dry weight, and total alkaloid content. Nitrate nitrogen content showed negative correlations with the contents of total alkaloids, sipeimine, and sipeimine glycosides, and positive correlations with the contents of amide nitrogen, peimine, peiminine, and peimisine. Amide nitrogen content was negatively correlated with sipeimine content. Fresh weight was positively correlated with total alkaloid content. Peiminine content exhibited a negative correlation with sipeimine content but positive correlations with the contents of peimisine and sipeimine glycosides. Conclusions: Inoculation with NFB effectively enhanced the contents of nitrogen forms in the rhizosphere soil of F. taipaiensis, as well as the biomass and medicinal components in the bulbs. The most pronounced effects were observed in the treatment group inoculated with R. aquatilis and P. stellifer.

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Keywords

Alkaloids; biomass; Fritillaria taipaiensis P. Y. Li; microbial fertilizer; nitrogen-fixing bacteria; soil nitrogen form

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