No abstract

No abstract

No abstract

ABSTRACT:The aim of this study was to evaluate the phytotoxic activity of aqueous extracts from mature leaves, stem bark and roots of Drimys brasiliensis Miers on germination and initial seedling development of two target species, Triticum aestivum L. (wheat) and Raphanus sativus L. (radish). The aqueous extract was prepared in a proportion of 10 g of plant powder, dissolved in 100 mL of distilled water, resulting in a 10% extract concentrate. Dilutions were made with distilled water to 7.5; 5.0; 2.5% and 0% (control). Germination and seedling growth bioassays were carried out under controlled laboratory conditions. The different plant parts exerted inhibitory effects on germination and early growth of wheat and radish, however, the extract obtained from the leaves was more effective in inhibiting the germination of radish. All plant parts of D. brasiliensis may constitute a promising source in the search for compounds capable of acting as natural phytotoxins.

-The objective of this study was to evaluate the effect of the ethanolic extract of Serjania lethalis leaves and stems on the diaspore germination and seedling growth of wild poinsettia (Euphorbia heterophylla) and barnyardgrass (Echinochloa crus-galli). The crude ethanolic extract was prepared from 100 g of dry plant material dissolved in 500 ml of ethanol. The extracts were solubilized in a buffer solution containing dimethyl sulfoxide (DMSO) at concentrations of 10.0, 7.5, 5.0 and 2.5 mg mL -1 . The effect of these extracts was compared with herbicide oxyfluorfen in bioassays. The ethanolic extracts of S. lethalis leaves and stems inhibited the germination and seedling growth of barnyardgrass and wild poinsettia in a concentration-dependent manner. The reduction in the root length of E. heterophylla seedlings might be attributed to the reduced elongation of metaxylem cells. The phytotoxicity of the extracts ranged according to the receptor species, and for some variables, the inhibitory effect was similar, and even superior, to that of the commercial herbicide. Thus, S. lethalis extracts might be a promising alternative for sustainable weed management.

Drimys brasiliensis Miers (Winteraceae), commonly called casca d'anta, is found in the Atlantic Forest and in Cerrado domain. It is considered an important source of natural compounds with pharmacological properties, however little is known about their phytotoxic potential on other plants. This study aims to evaluate the phytotoxic effects of D. brasiliensis leaf extracts collected in two seasons (dry and rainy) on the germination and seedling growth of Sesamum indicum L., as well as evaluating the effect of the most active extract on metaxylem cell size in the roots of the target species. The aqueous extract was prepared with 10 g of dried, ground leaves dissolved in 100 mL of distilled water, resulting in a 10% extract concentrate. Dilutions were made with distilled water to 7.5; 5.0; 2.5% and 0% (control). The leaf extracts showed phytotoxicity on germination and early growth of sesame, with more pronounced activity in leaves collected in the dry season. The inhibitory effects were observed at the cellular level in sesame roots, with a significant reduction in the size of the metaxylem cells in the presence of all concentrations of leaf extract. The extract from leaves of D. brasiliensis may constitute a promising source in the search for natural phytotoxins for use in sustainable agriculture practices.Key words: inhibition, seasonality, germinability, metaxylem, sesame. RESUMEN Drimys brasiliensis

No abstract

http://dx.doi.org/10.5007/2175-7925.2016v29n1p1O objetivo deste estudo foi avaliar o efeito do extrato etanólico de folhas e frutos de Banisteriopsis oxyclada sobre o crescimento de plântulas de amendoim-bravo e capim-arroz. O extrato bruto etanólico foi preparado na proporção de 100 g de material vegetal seco para 500 mL de etanol. A partir deste, os extratos foram solubilizados em solução tampão e dimetil sulfóxido (DMSO), nas concentrações 10,0; 7,5; 5,0 e 2,5 mg/mL. Foi avaliado o crescimento do sistema radicular, da parte aérea e das células do metaxilema radicular das plântulas. Os extratos etanólicos de folhas e frutos de B. oxyclada exerceram atividade inibitória no crescimento radicular de plântulas de capim-arroz e amendoim-bravo, com efeito dependente da concentração. Foi observada redução no crescimento da parte aérea apenas nas plântulas de amendoim-bravo. A redução no crescimento radicular das plântulas de amendoim-bravo pode estar relacionada à diminuição no alongamento das células do metaxilema. Banisteriopsis oxyclada apresenta propriedades itotóxicas e pode ser considerada uma alternativa no controle das plantas daninhas estudadas, com base em produtos naturais.