Ecological response of Angelica dahurica and its rhizosphere microorganisms to treatments of Alternanthera philoxeroides

To explore the ecological adaptation mechanism of the medicinal plant Angelica dahurica and its rhizosphere microorganisms to the invasion of Alternanthera philoxeroides. This study analysed the physiological and biochemical indexes of A. dahurica seedlings and soil enzyme activities under a series concentration of root, stem and leaf extracts from A. philoxeroides. Furthermore, high-throughput sequencing technology was used to detect the rhizosphere microorganism diversity of A. dahurica. Results showed that with the increase of extract concentration and the extension of treatment time, the activity of antioxidant enzymes (SOD, POD, CAT) in seedlings increased and then decreased, and the inhibitory effect of root extract was the most significant. The extract effect on soil enzyme activity followed the descending sequence: root stem leaf. The activities of soil enzymes S-{beta}-GC, S-LAP and S-ALP showed an upward trend with the increase of extract concentration, and the highest enzyme activity was found at 80 g/L. Proteobacteria, Acidobacteria, Bacteroides and Sphingomonas were the dominant species of rhizosphere soil bacteria under the treatment of each extract at phyla level. With the increasing concentration of different organ extracts, the relative abundance of Proteobacteria, Bacteroides and Sphingomonas gradually increased, while the abundance of Acidobacteria decreased. PcoA principal component analysis revealed a significant differentiation between rhizosphere bacterial community structure under the extract and control treatments. These results indicated that different concentrations of A. philoxeroides extract could affect the growth and soil enzyme activity of A. dahurica and change the community structure of rhizosphere microorganisms.