Nitrogen Addition Changes the Allelopathic Effects of the Root Leachate from the Invasive Weed Stellera chamaejasme L. on a Dominant Grass in the Songnen Grassland
2023
Chen, C. | Xing, F. | Li, Z. | Zhang, R.H.
Invasive weeds that are poisonous to animals may affect the growth of neighboring palatable plants by releasing allelochemicals in degraded grasslands. Nitrogen (N) input may promote the growth of plants and alter the soil and plant nutrient content and their stoichiometric ratios. However, it is unclear how N addition mediates allelopathic effects of unpalatable weeds on adjacent plants. In this study, a greenhouse experiment was performed to detect the combined effects of root leachate of an invasive and unpalatable weed, Stellera chamaejasme, and N addition on the phenotypic traits and nutrient stoichiometry of a dominant grass, Leymus chinensis, in the Songnen grassland, China. The results showed that leachate addition had no significant effects on traits such as ramet number and biomass but significantly decreased total carbon (C) and the C:N ratio and increased total N in the shoots of L. chinensis. Furthermore, higher N addition changed the original allelopathic effects of the leachate by changing the soil pH, N and phosphorous availability, and microbial activity. This study emphasizes the significance of stoichiometry for detecting plant allelopathy. In particular, N deposition and plant allelopathy should be considered in assessing the relationships between invasive weeds and palatable plants in degraded grasslands.
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