Can Allelopathic Grasses Limit Seed Germination and Seedling Growth of Mutambo? A Test with Two Species of Brachiaria Grasses

Abstract

-Tree establishment in pasture areas can be inhibited, at least in part, by exotic grasses allelopathy and this can represent an important limitation by changing the patterns of both germination and seedling growth of tree species. This study aims to evaluate the allelopathic potential of Urochloa brizantha and U. decumbens on germination, growth and metabolism of Guazuma ulmifolia seedlings. We performed bioassays evaluating the effect of the crude ethanol extract and semipurified fractions (hexane fraction, ethyl acetate fraction and ethanol-water fraction) of U. brizantha and U. decumbens using completely randomized design, with four concentrations (0, 250, 500, 1,000 mg L -1) and four replications. The variables analyzed were germination percentage, mean germination time, shoot and root growth, catalase and peroxidase activity, chlorophyll content and root respiration. The results showed that both grasses have an inhibitory effect on G. ulmifolia metabolism, affecting both germination and seedlings growth and inducting metabolic defense. Thus, these results show that the grass species evaluated have the potential to restrict the re-introduction of G. ulmifolia in pasture areas due to interference competition.Keywords: Guazuma ulmifolia, interference competition, exotic grasses, direct sowing, restoration, Urochloa. RESUMO -O estabelecimento

The amazonian capim-açú is less nitrogen dependente than antelope grass to produce leaf dry matter

“…The best results of leaf dry matter production of the native capim-açú are in agreement with those found by Costa et al (2013), reinforcing the idea that native species have relatively lower N demand (Shivega & Aldrich-Wolfe, 2017) compared to exotic species (Oliveira et al, 2016).…”

Impact of invasive grasses on Cerrado under natural regeneration

“…As data was expressed as abundance (%) and is therefore upper limited, we used the chord distance to generate the dissimilarity matrix for both analyses (Orlóci 1967). Statistical analyses were performed in the R program (R Development Core Team 2016) with the packages nlme (Pinheiro et al 2016), vegan (Oksanen et al 2016) and multcomp (Hothorn et al 2008).…”

Chemical Screening of <i>Urochloa humidicola</i>: Methods for Characterizing Secondary Metabolites and Allelopathic Activity on Forage Legumes

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