A hybrid of the invasive plant Sphagneticola trilobata has similar competitive ability but different response to nitrogen deposition compared to parent

Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) is native to Mexico and Central America. The species is spreading quickly and has naturalized in more than 70 countries. It has often been recorded as a harmful invasive plant that disturbs native plant communities. Phytotoxic chemical interactions such as allelopathy between invasive plants and native plants have been reported to play an important role in the invasion. Evidence for allelopathy of T. diversifolia has accumulated in the literature over 30 years. Thus, the objective of this review was to discuss the possible involvement of allelopathy in the invasive potential of T. diversifolia. The extracts, root exudates, and plant residues of T. diversifolia inhibited the germination and growth of other plant species. The soil water and soil collected from T. diversifolia fields also showed inhibitory growth effects. The decomposition rate of T. diversifolia residues in soil was reported to be high. Phytotoxic substances such as sesquiterpene lactones were isolated and identified in the extracts of T. diversifolia. Some phytotoxic substances in T. diversifolia may be released into the soil through the decomposition of the plant residues and the exudation from living tissues of T. diversifolia, including its root exudates, which act as allelopathic substances. Those allelopathic substances can inhibit the germination and growth of neighboring plants and may enhance the competitive ability of the plants, make them invasive.

Download Full-text

Pennisetum Hydridum’s Potential for Controlling Invasive Chromolaena Odorata

Sustainability ◽

10.3390/su11215990 ◽

2019 ◽

Vol 11 (21) ◽

pp. 5990

Author(s):

Qiu-Yuan Xu ◽

Dan Wang ◽

Guo-Ming Quan ◽

Jia-En Zhang ◽

Rong-Hua Li ◽

...

Keyword(s):

Invasive Plants ◽

Competitive Ability ◽

Invasive Plant ◽

Control Method ◽

Soil Nutrient ◽

Invasive Plant Species ◽

Chromolaena Odorata ◽

Nutrient Contents ◽

Morphological And Physiological Traits ◽

Soil Nutrient Contents

The exotic Chromolaena odorata is one of the most destructive invasive plant species in South China, and hence an efficient and sustainable control method is urgent. One method, replacement control, which eliminates harmful plants by introducing another competitive plant, is being used increasingly for controlling invasive plants. To test the potential of Pennisetum hydridum to control C. odorata, a series of polyculture experiments with different proportions of the two species was conducted. Competitive indices, plant morphological and physiological traits, and soil nutrient contents were measured to test the impacts of P. hydridum on C. odorata. The presence of P. hydridum significantly suppressed growth of C. odorata, and P. hydridum was not sensitive to the presence of C. odorata. Moreover, increased root/shoot ratios of P. hydridum enhanced its underground competitive ability, and competition between the two species resulted in remarkable reductions of soil nutrient contents which would further decrease the competitiveness of the invasive C. odorata. In summary, our results suggest that P. hydridum is a prospective candidate to control C. odorata.

Download Full-text