The relationship between selected rhizosphere and non-rhizosphere soil properties and the quality of Pyrola decorata

Abstract

Pyrola decorata is a native plant species on Mt. Taibai in the Qinling Mountains. Because of its medicinal value, a large amount of wild P. decorata has been excavated in recent years. As a result, the P. decorata population on Mt. Taibai has gradually decreased. In order to protect P. decorata, it is important to study the relationship between P. decorata quality and selected chemical properties of rhizosphere and non-rhizosphere soil. Plant and soil samples were collected from different habitats on Mt. Taibai and taken to a laboratory for analysis. The plant samples were analyzed to determine the total flavonoid, tannin, hyperin, and quercetin content of P. decorata. The antioxidant activity (DPPHIC50) of the samples was also determined. Correlation analysis, principal component analysis, regression analysis, and path analysis were conducted to determine the relationship between medicinally active compounds in wild P. decorata and selected properties of rhizosphere and non-rhizosphere soil. The results indicated that in rhizosphere soil, available potassium concentration, pH, and urease were positively correlated with individual compounds in P. decorata. In contrast, for non-rhizosphere soil, available potassium was significantly correlated with five active compounds. In rhizosphere soil, available potassium, pH, invertase, and urease were the main factors influencing the active compound content of P. decorata, whereas in non-rhizosphere soil available nitrogen, available potassium, pH, and invertase were the main factors. In rhizosphere soil, available potassium was the most important factor influencing the active compound content, whereas soil pH, catalase, and acid phosphatase were the main limiting factors. In non-rhizosphere soil, available nitrogen and available potassium were the most important factors influencing the active compound content, whereas soil pH and invertase were the main limiting factors. In conclusion, the content of active compounds in of P. decorata is affected by multiple soil factors, especially soil available potassium, soil pH, and invertase.