Seed‐to‐seed allelopathic effects between two invaders of burned Pampa grasslands

Abstract

The establishment of Lotus tenuis can interfere with colonization by Carduus acanthoides during the early post‐burn recovery of Flooding Pampa grasslands. The purpose of this research was to determine the potential role of L. tenuis seeds as a source of allelopathic compounds involved in that interaction. Imbibed seeds of L. tenuis and aqueous leachates from them were bioassayed for their ability to inhibit germination and seedling growth of C. acanthoides, both on sterilized filter paper and on pasteurized soil as substrata. Germination and/or emergence of C. acanthoides were inhibited and root length was reduced on filter paper or soil, by both the presence of L. tenuis seeds and their leachate, at densities of L. tenuis near the maximum values observed in the field. Germination and seedling growth of C. acanthoides were less affected by the presence of L. tenuis seeds than by the addition of their leachate, and the presence of L. tenuis seeds or their leachate showed stronger effects on emergence of C. acanthoides from soil than on its germination on filter paper. Methods applied for leachate sterilization, ultrafiltration or autoclaving did not modify C. acanthoides responses. Neither the germination rate nor the root length of C. acanthoides seedlings were affected by solutions of polyethylene glycol with similar osmolarity to the leachates. We conclude that the release of inhibitory substances on to filter paper and into pot soil from imbibed L. tenuis seeds would be the mechanism responsible for the observed effects.

Allelopathic evidence in Brachiaria decumbens and its potential to invade the Brazilian Cerrados

“…decumbens organs (green leaves, roots and senescent leaves) at different concentrations ( Higashinakasu et al (2004) in seven crop and weed species, and by Laterra and Bazzalo (1999) between two invasive species of the pampa grasslands (Argentina).…”

Allelopathic and autotoxicity effects of barley (Hordeum vulgare L. ssp. vulgare) root exudates

“…Multiple studies have found evidence for the existence of 'seed-to-seed' allelopathic effects by seed leachate or root exudates (Liu and Lovett 1993a;Kushima et al 1998;Laterra and Bazzalo 1999;Zhang et al 2011), but in most cases this experimental protocol does not exclude, on one hand, the effect of competition, and on the other hand, the possible effect of volatile organic compounds (VOCs), known to participate in plant communication and interactions (Ninkovic 2003;Kellner et al 2010;Gfeller et al 2013;Fiers et al 2013). …”

Phytotoxicity induced by Phragmites australis: an assessment of phenotypic and physiological parameters involved in germination process and growth of receptor plant

“…The OP of all extract concentrations in different organs was in the range of (0.048 to (1.27 bar. In bioassays such as that carried out here, OPs in this range could affect the germination and growth (Laterra & Bazzalo 1999), so we also evaluated the OP effects on the abovementioned parameters of the test species.…”