Effects of Datura stramonium L. Invasion into Different Habitats on Native Plant Functional Traits and Soil Carbon, Nitrogen and Phosphorus Stoichiometric Characteristics.

Datura stramonium is an invasive herb of the family Solanaceae from Mexico and has been invading seriously in China. The effects of invasive plants on the functional traits of native plants and the stoichiometric characteristics of soil carbon, nitrogen and phosphorus in different habitats were explored by taking the invasive plant D. stramonium and coexisting native plants as the research object. The species, quantity and height of plants in sample plots in farmland, wasteland and roadside habitats were investigated and the specific leaf area (SLA), leaf carbon content (C), nitrogen content (N), carbon-to-nitrogen ratio (C:N), construction cost (CCmass) and stoichiometric characteristics of soil carbon (C), nitrogen (N) and phosphorus (P) were analyzed. The results showed that compared with the noninvaded area, the species and quantity of native plants decreased in the invaded area, and SLA and leaf N showed a decreasing trend. The plant height of native plants in the invaded area of the farmland and wasteland decreased by 23.19% and 15.26%, respectively, while the height of native plants along the roadside increased by 95.91%. The leaf C:N ratio of native plants in the invaded area along the roadside significantly increased by 54.07%. The plant height and leaf N of D. stramonium in the three habitats were higher than those of the native plants. The soil N in the invaded area of the three habitats increased, with the soil N in the farmland increasing by 21.05%, in the wasteland increasing by 9.82% and along the roadside significantly increasing by 46.85%. The soil carbon-to-phosphorus ratio (C:P) in the three habitats showed an increasing trend. The soil C:P ratio in the farmland increased by 62.45%, in the wasteland it increased by 11.91% and along the roadside it significantly increased by 71.14%. These results showed that invasion by D. stramonium has a great effect on the local ecosystem, and it has a high ability to capture resources. D. stramonium can improve its own competitiveness by enhancing invasiveness by changing the functional traits of native plants and the stoichiometric characteristics of soil C, N and P, which may be the reason for its invasive success.

Abscisic acid-generating bacteria can reduce Cd concentration in pakchoi grown in Cd-contaminated soil.

Contamination of vegetable plants with cadmium (Cd) has become a serious issue in recent years. In the present study, pakchoi (Brassica chinensis L.) grown in Cd-contaminated soil inoculated with abscisic acid (ABA)-generating bacteria, Azospirillum brasilense and Bacillus subtilis, showed 28%-281% and 26%-255% greater biomass, and 40%-79% and 43%-77% lower Cd concentrations, respectively, than those of the controlbacteria-free plants. These treatments also alleviated the Cd-induced photosynthesis inhibition and oxidative damage (indicated by malondialdehyde [MDA], H2O2, and O2• -). Furthermore, the application of bacteria also remarkably improved the levels of antioxidant-related compounds (total phenolics, total flavonoids, ascorbate, and 2,2-diphenyl-1-picrylhydrazyl [DPPH] activity) and nutritional quality (soluble sugar and soluble protein) in the Cd-supplied plants. Based on these results, we conclude that the application of ABA-generating bacteria might be an alternative strategy for improving the biomass production and quality of vegetable plants grown in Cd-contaminated soil.