Andreya Kalyana de Oliveira

Atividade alelopática de extrato de sementes de juazeiro

Allelopatic activity of juazeiro seed extract Allelopathy is the release of plant substances that inhibit or act as stimulants in the environment, and may be present in the seeds of some species. The objective of this work was to evaluate the allelopatic activity of the extract of juazeiro (Ziziphus joazeiro Mart.) seeds on the germination of lettuce (Lactuca sativa L.) seeds. We utilized the randomized design with four replications and five treatments (0, 25, 50, 75 and 100% of concentration of the crude extract). The crude extract was obtained after the extraction of 50 g of seeds, shaking them with 500 mL of water in a blender. The results showed allelopatic effect, proportional to the increase of the concentration of the extract. The highest concentrations of seed extract of juazeiro affected the percentage and speed of germination and the lowest concentrations caused abnormal seedlings on lettuce seed germination. Therefore, the extract presented an allelopatic effect, unfavorable to the germination of lettuce seeds.

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.

Envelhecimento acelerado para avaliação do potencial fisiológico de sementes de melão

The accelerated aging test can be useful for quality control of vegetable seeds. However, there are factors which can affect the results, so it is necessary to adjust the methodology to obtain consistency. This study was carried out with the main objective of evaluating procedures for performing accelerated aging test to estimate the physiological potential of melon seeds, including the use of saturated solution of NaCl of water. Seeds of two melon hybrids (Goldex and Vereda), each one represented by five lots, were submitted to germination tests, first germination counting, electrical conductivity (16 and 24 hours of imbibition), plant emergence in greenhouse and accelerated aging. In the last, two procedures were used: traditional (water) and saturated solution (40 g 100 mL-1) of NaCl at 41oC for 24, 48 and 72 hours. A completely random design was used with four replications and single analysis for each test. The tests of first germination counting and plant emergence were efficient to identify seed lots of inferior quality. But the electrical conductivity test was not efficient for evaluation of seed vigor. The accelerated aging test (traditional procedure and with saline saturated solution), using the period of 72 hours at 42oC, shows to be adequate for evaluating the physiological potential of melon seeds. In comparison with the use of water, the utilization of saline solution in the accelerated aging test inhibited significantly growth and development of fungi.

Pré-tratamento com ácido sulfúrico na germinação de sementes de Ziziphus joazeiro Mart: Rhamnaceae

RESUMO: Ziziphus joazeiro Mart. e uma arvore brasileira endemica da Caatinga e tem diversos usos no Nordeste. As sementes apresentam dormencia tegumentar e o presente trabalho teve por objetivo avaliar tratamentos pre-germinativos com acido sulfurico concentrado para superar a dormencia. O delineamento experimental utilizado foi o inteiramente casualizado, com 9 tratamentos, sendo 0, 30, 60, 90, 120, 150, 180, 210 e 240 minutos de imersao em acido sulfurico concentrado P.A. com tres repeticoes de 50 sementes, em dois experimentos. No experimento 1 foram usadas sementes recem coletadas e a avaliacao foi feita durante 140 dias. No experimento 2 foram usadas sementes armazenadas por 5 meses e a avaliacao feita durante 100 dias. Ziziphus joazeiro apresenta dormencia imposta pelo endocarpo que envolve as sementes, e e necessario o uso de acido sulfurico durante 180 minutos para sementes recem-coletadas e por 240 ou 270 minutos, para sementes armazenadas por 5 meses para se atingir 80% de emergencia. O tempo de armazenamento das sementes pode influenciar a resposta germinativa, com emergencia mais rapida apos o armazenamento por 5 meses. Palavras-chave: Ziziphus joazeiro, dormencia, pre-tratamento quimico, escarificacao

Atividade alelopática de extratos de diferentes partes de juazeiro (Ziziphus joazeiro Mart. - Rhamnaceae)

O objetivo neste trabalho foi avaliar o potencial alelopatico do extrato de cascas e de folhas juazeiro (Ziziphus joazeiro Mart.) sobre as sementes de alface (Lactuca sativa L.). Foram conduzidos dois experimentos, em ambos foi usado o delineamento inteiramente casualizado. No primeiro foram realizadas quatro repeticoes e cinco tratamentos (EF - extrato de folhas a 100 oC, EF - extrato de folhas a 25 oC, EC - extrato de cascas a 100 oC, EC - extrato de cascas a 25 oC, e agua destilada). No segundo foram realizados cinco tratamentos (0%, 25%, 50%, 75% e 100% de concentracao do extrato bruto) e quatro repeticoes com 20 sementes de alface. O extrato bruto foi obtido apos a agitacao das cascas e das folhas com agua em liquidificador utilizando-se 50 g de material para 500 ml de agua. Os resultados mostraram efeito do extrato dependendo da concentracao. Os extratos brutos e diluidos de Z. joazeiro nao afetaram a germinacao, mas nas maiores concentracoes causaram elevada porcentagem de plântulas anormais e o extrato de folhas e de cascas extraido a 100 oC reduziram o crescimento da raiz e parte aerea. Extratos aquosos de cascas e de folhas de Z. juazeiro apresentam efeito fitotoxico na germinacao de sementes de L. sativa.

Propagação vegetativa de liamba, planta medicinal

The liamba (Vitex agnus castus L.) is used as a medicinal species in Brazil and presents compounds with similar chemical structure to progesterone. To evaluate the propagation of liamba two experiments were carried out. The first, using shoot cuttings with 20 cm long, leafless and classified into two groups, apical and basal. The cuttings were standardized in their thickness of 3 to 5 mm in diameter and 40 units of each type were placed in polyethylene bags (10 x 30 cm) filled with soil + manure in the volumetric ratio of 2:1. The second, with shoot minicuttings of the plant canopy with 3 to 5 cm long, without leaves and in a randomized block experimental design with four replications of 20 minicuttings, in a factorial 2 x 3. The treatments were kind of mini-cuttings (with and without hell) and substrate (soil, soil + cattle manure and soil + compost). The vegetative propagation of liamba can be made by basal cuttings or minicuttings with heel in soil + compost.