Maria de Fatima Barbosa Coelho

Alelopatia de extratos de diferentes órgãos de mulungu na germinação de alface

The coral tree (Erythrina velutina) is a fast growing tree with medicinal properties. The aim of this study was to evaluate the allelopathic effects of aqueous extract of seeds, flowers and bark of coral tree on seed germination and seedling development of lettuce cv. Monica SF FI. The experimental design was completely randomized with seven treatments [seed extract at 100°C, seed extract at 25°C, bark extract at 100°C, bark extract at 25°C, flower extract at 100°C, flower extract at 25°C and distilled water (control)] with four replications. The extracts of seeds, independent of the extraction temperature decreased the percentage and speed of germination of lettuce and affected the development of the seedlings. The other extracts did not affect germination, but caused the appearance of abnormal seedlings and dead. The aqueous extract of seeds of coral tree has allelopathic potential in the seeds of lettuce cv. Monica SF FI.

Procedência do fruto e substratos na germinação de sementes de Pseudobombax longiflorum (Mart. et Zucc.) A. Robyns

The Imbirucu [ Pseudobombax longiflorum (Mart. et Zucc.) A. Robyns] is an arboreous species that occurs in the Brazilian Savannah. The exploitation and destruction of this biome have reduced the P. longiflorum populations and studies on its germination are crucial for preserving it. This study aimed to evaluate the germination process of two populations of P. longiflorum seeds, on different substrates. A completely randomized design, in a 2x5 factorial scheme (two populations x five substrates), was used, with five replications of 50 seeds for each treatment. The sampled populations were collected in Rondonopolis and Cuiaba, in the Mato Grosso State, Brazil. Substrates consisted of black soil, vermiculite, sand, black soil + vermiculite (1:1) v/v, and black soil + sand (1:1) v/v. The germination percentage of viable and dead seeds, seeds with fungi, and the mean germination time were evaluated. The highest germination rate was observed in the sand substrate (78%), in seeds from Cuiaba, and in the sand and vermiculite substrates (36.6%), in seeds from Rondonopolis. The mean germination time ranged from 10.6 to 16.5 days, for the seeds from Rondonopolis, and from 14.7 to 18.1, for the ones from Cuiaba. The seeds from Rondonopolis, in the black soil substrate, presented a 66.7% mortality rate, with the presence of the Fusarium and Rhizoctonia fungi genera. The P . longiflorum seeds from Cuiaba showed a higher germination rate than those from Rondonopolis, being the most suitable ones for the seedlings production. The sand substrate is the recommended one for the P . longiflorum seeds germination due to its greater ease of acquisition and lower cost.