Effects of endophytic fungus Y118 on physiological and biochemical indexes and quality improvement of Zanthoxylum nitidum (Roxb.) DC

Abstract

To understand the effects of endophytic fungus Y118 on the physiological characteristics of Zanthoxylum nitidum (Roxb.) DC after co-culture with its host Zanthoxylum nitidum, we measured the plant growth index (dry root weight) of Zanthoxylum nitidum at different growth stages using the solid fermentation medium containing endophytic fungus Y118. Physiological and biochemical indexes (defensive enzyme activity) were determined by chromatographic analysis of the contents of nitidum chloride and chelidonine, the main active ingredients in Zanthoxylum nitidum root. At 3, 6, 9 and 12 months, the root dry weight of Y118 treatment group was significantly increased by 1123.53%, 51.08%, 56.40% and 47.12% compared with the control group, respectively. At the 3-month mark, superoxide dismutase (SOD) activity exceeded that of the control. After 9 months of cultivation, peroxidase (POD) activity in the treatment group showed a significant difference at a 0.05 significant level. At the 3-month mark, phenylalanine ammonia lyase (PAL) activity in the treatment group was significantly higher than that in the control group, increasing by 187.21%. After 12 months of cultivation, the contents of chlorophyll a and chlorophyll b significantly increased by 45.28% and 28.87%, respectively, compared with the control group. After 9 and 12 months of co-culture, the contents of nitidine chloride in Zanthoxylum nitidum in the Y118 treatment groups were 0.783 and 0.904 mg/g, respectively, showing a significant increase of 42.11% and 44.18% compared with the control group; the contents of chelidonine were significantly increased by 40.73% and 26.57% compared with the control group. Inoculation with the endophytic fungus Y118 significantly improved the physiological tolerance of Zanthoxylum nitidum and promoted the growth of Zanthoxylum nitidum, thereby enhancing the quality of Zanthoxylum nitidum. This implicates Y118 as a potential artificial fertilizer for Zanthoxylum nitidum.