Natural selection for resistance to the allelopathic effects of invasive plants

Abstract

Summary1 Exotic plant invasions often cause high mortality in native populations and therefore have the potential to be a powerful selective force. 2 We found that surviving individuals from North American communities that have experienced extensive invasion by Centaurea maculosa have higher tolerances to the Eurasian invader than individuals from communities that did not experience invasion. 3 Some native species grown from the seed of individuals that survived Centaurea invasion were more resistant to the general competitive effects of Centaurea , the root exudates from Centaurea , and to a chemical specific to the root exudates of Centaurea ( ± )-catechin. 4 Although these results may be confounded by maternal effects, they provide initial evidence that native plant species may evolve to tolerate the effects of an exotic invader, and in particular an invader's novel allelochemistry. 5 Such effects may have long-term implications for plant invasions and the organization of plant communities. Evolved tolerance may ultimately contribute to coexistence among natives and invaders, with our results suggesting that natural plant communities may be more coevolved and less individualistic than currently thought.

Anthropogenic fire drives the evolution of seed traits

“…Our results demonstrate that anthropogenic fire has shaped adaptive traits in H. aromaticum populations, thus challenging the widespread assumption that native plant species from the Chilean matorral are not adapted to fire because of its historical absence as a natural disturbance (13,14). A recent study reported an increase in the species richness of native annuals in several matorral communities following fires (18), which suggests that fire adaptations might be rather common in matorral species.…”

Evolutionary limits ameliorate the negative impact of an invasive plant

“…As A. petiolata can form dense patches in just a few generations (28), selection pressures may quickly switch to favor lower glucosinolate levels. The selective benefit of allelopathic traits may also decrease over time if native plants or soil microbes evolve resistance, and this resistance is great enough to render the allelochemical ineffective (29). Ultimately, confidently determining the primary mechanisms creating the patterns that we have observed will require experimental approaches.…”

Comparative Effect of Water Extract of Parthenium Hysterophorus, Datura Alba, Phragmites Australis and Oryza Sativa on Weeds and Wheat

“…Autotoxicity at high expression levels decreases the germination, growth and yielding ability of a plant (Ben-Hammouda et al 2002). Experimental examination of allelopathy can also vary with extraction approaches, techniques to isolate specific allelochemicals and the substrate used (Callaway et al 2005). However, the incorporation of these weeds in the soil might be proved effective to inhibit the seed germination of weeds but how to avoid these allelochemicals not to affect the seed germination of the crop is a question that needs to be addressed on scientific backgrounds.…”