Phytotoxic Potential of the Crude Extract and Leaf Fractions of Machaerium hirtum on the Initial Growth of Euphorbia heterophylla And Ipomoea grandifolia

Abstract

Allelopathy is the term used to define any process involving secondary metabolites produced by plants and microorganisms that influence growth and development of agrobiological systems. Currently, it is sought to find allelochemicals of interest and know how to apply them in bio-herbicides to combat weeds. In this study, the effects of the crude leaf extract and fractions of Machaerium hirtum (Vell.) Stellfeld were analyzed on Euphorbia heterophylla L. (wild poinsettia) and Ipomoea grandifolia (Dammer) O’Donell (morning glory), as well as the occurrence of morphoanatomical changes. For this, 0.04 g of the crude extract and fractions were solubilized and diluted (50 mL) to concentrations of 0.1, 0.2, 0.4, and 0.8 g L-1 (m/v). Initial growth tests were performed on Petri dishes containing two paper sheets and seedlings of weed species with the respective treatments, being maintained in a germination chamber for 48 hours at 25 oC. Distilled water was used as a control. Shoot and root length was assessed in the initial growth. The percentage of inhibition was calculated based on the values obtained in the initial growth bioassays. Morphologically altered wild poinsettia seedlings were fixed and sectioned transversely for anatomical analysis. The results indicated significant changes in length, being wild poinsettia seedlings more sensitive when compared to those of morning glory. Morphologically altered seedlings presented root necrosis as the most frequent symptom. Anatomically, parenchymatic cells of the hypocotyl and roots of wild poinsettia seedlings presented smaller and irregularly shaped cells when compared to the control, causing significant reductions in the measured parameters.

Euphorbia retusa (Forssk.) A PROMISING SOURCE FOR BIOACTIVE COMPOUNDS IN BIOMEDICAL AND AGRICULTURE APPLICATIONS

“…This could be ascribed to the radicle was the first to emerge and consequently direct contact with the extracts or due to the organ-based sensitivity of the species to phytotoxic compounds. Previous studies (Abd El-Gawad et al, 2018a;Ximenez et al, 2019) also documented this aspect of greater root than shoot inhibition. At higher concentration (40 mg ml -1 ) the germination of the tested seed was highly inhibited by 51.77%, while the shoot and root were reduced by 60.98% and 74.55%, respectively (Figures 2).…”

Avances en el desarrollo de nuevos herbicidas biológicos a partir de extractos vegetales fitotóxicos aplicados in vitro

“…y pastos de corral (Rany Das; Iwasaki; Suenaga; Kato-Noguchi, 2019), usando concentraciones de 300 mg en base seca de Crescentia alata Kunth, logrando una inhibición del 100 % del crecimiento de los brotes y raíces del berro, lechuga, ryegrass italiano y Timothy. Murari, Kumar y Pragati (2014) mencionaron que la germinación de semillas y la longitud de radícula de Vigna sinensis L. disminuyeron al usar extracto de hoja de Calotropis gigantea L. Cabe mencionar que al disminuir su longitud disminuye el peso, pérdida documentadas por muchos investigadores (Watanabe et al, 2014;Ma et al, 2018;Ximenez;Santin;Ignoato;Pastorini, 2019). Javaid, Shafique, Kanwal y Shafique (2010) observaron otro factor, "el amarillamiento de las plántulas de partenio (Parthenium hysterophorus L.) usando flavonoides de mango (Mangifera indica L.)".…”

Environmental conditions affect herbicide selectivity on paddy rice in Southern Brazil

“…Herbicide selectivity is dependent on crops and is highly dependent on environmental conditions, especially temperature (XIMENEZ et al, 2019). The cold stress can impair or affect the whole plant metabolism, harming the plant protection mechanisms indirectly against biotic and abiotic stresses (THEOCHARIS et al, 2012).…”