Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Allelopathy of Solidago canadensis with different invasion degrees under nitrogen deposition.

Abstract

Increased global nitrogen deposition has been seen as a possible new driver for the expansion of many invasive plants. But its mechanism of action remains unclear. Therefore, this study aimed to examine the effects nitrogen deposition on the invasion degree of a worldwide clonal invasive weed Solidago canadensis. To conduct this research, three kinds of nitrogen levels(N0, N5 and N12)were set up to simulate different degrees of nitrogen deposition and five different competition levels(intraspecies and interspecies)through controlled simulation experiments to obtain S. canadensis litter. Then the allelopathy of the extract of the S. canadensis litter leaf on Lactuca sativa seeds was studied. The results were as followes:(1)Solidago canadensis litter of different invasion levels under N0, N5 and N12 nitrogen addition treatment significantly inhibited the germination and growth of Lactuca sativa. In addition, the allelopathic effect of the extract at the initial stage of invasion(S1A3)under the addition of N5 was the most significant, and its germination speed index, germination vitality index, root length, plant height, and leaf length were respectively reduced by 61%, 79%, 84%, 68% and 13% compared with the control. At this time, the total phenol and total flavonoid content in litter were 0.48 mg.g-1and 1.50 mg.g-1, respectively.(2)Under the same nitrogen addition, the degree of invasion had a significant effect on the allelopathic effect of Solidago canadensis. With the increase of the proportion of Artemisia argyi, the allelopathic effect of the extract significantly increased and the content of litter allelochemicals in the early invasion(S1A3)was significantly higher than that in the late invasion(S3A1).(3)When the invasion degree is the same, the allelopathic effect of N5 nitrogen addition treatment is significantly higher than that of N0 or N12 nitrogen addition treatment.(4)Nitrogen addition has an interaction with the degree of invasion and their combined effect significantly affects the allelopathic effect of Lactuca sativa seeds. It can be inferred that nitrogen deposition may enhance the allelopathic inhibition effect of Solidago canadensis litters on native plants and further promote the successful invasion of invasive plants. This study provides a theoretical reference for further research on the allelopathy and ecological control of S. canadensis.