Fabrícia Nascimento de Oliveira

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.

Produtividade e morfologia de acessos de caupi, em Mossoró, RN

The objective of this work was to evaluate the productivity and to describe the morphology of ten cowpea [Vigna unguiculata (L.) Walp.] accessions in the edaphoclimatic conditions of Mossoro, Brazil. The accessions Amapa, BRS Potiguar, Canapu, Casca-de-seda, Coruja, Costela-de-vaca, Joao-vieira, Pingo-de-ouro, Rabo-de-peba and Sempre-verde were evaluated in a field experiment from August 2006 to June 2007. The majority of accessions was of indeterminate and semi-branched voluble growth habit; only BRS Potiguar was semibranched. The number of seeds per pod varied from 12 to 16. For the Mossoro region, the accession Amapa is considered be the best alternative for small farmers. This accession is earlier maturing, presents a high number of pods per plant and high yield. Other promising genotypes are BRS Potiguar and Casca-de-seda.

Temperaturas e substratos na germinação de sementes de pereiro-vermelho (Simira gardneriana M.R. Barbosa & Peixoto)

O pereiro-vermelho e uma especie florestal pertencente a familia Rubiaceae, considerada endemica do bioma Caatinga. O presente trabalho teve como objetivo definir o tipo de substrato e a temperatura mais adequados para a germinacao de sementes de pereiro-vermelho (Simira gardneriana M.R. Barbosa & Peixoto). Dessa forma, realizou-se experimento em delineamento inteiramente ao acaso e arranjo fatorial 5 x 4, constituidos pelas combinacoes de cinco substratos (entre areia, sobre areia, rolo de papel, sobre papel e sobre vermiculita) e quatro temperaturas (constantes de 25; 30; 35 °C e alternada de 20-30 °C), com quatro repeticoes de 25 sementes cada. Foram analisadas as seguintes variaveis: porcentagem de germinacao, porcentagem de plântulas anormais, indice de velocidade de germinacao, comprimento e massa seca das plântulas. As temperaturas de 25 e 30 °C e os substratos rolo de papel ou areia sao condicoes ideias para a germinacao das sementes de pereiro-vermelho.

Qualidade fisiológica de sementes de girassol avaliadas por condutividade elétrica

The seed quality evaluation is essential in quality control programs. Thus, vigor tests have been developed to differentiate seed lots, due to the limitations of the germination test. This study aimed at evaluating the electrical conductivity test efficiency for determining the physiological quality of sunflower seeds. Ten lots of sunflower seeds (Catissol and Multissol cultivars) were used. Initially, the quality of each lot was determined, besides the seeds moisture content, by using tests of germination, first counting and seedling emergence, in a greenhouse. Then, the seeds were submitted to the electrical conductivity test, for four soaking periods (6, 12, 18 and 24 hours), by using disposable plastic cups containing 25 and 50 seeds, in 50 mL and 75 mL of deionized water, at 25°C and 30°C. The experimental design was completely randomized, in a 5x4 factorial scheme (five lots and four soaking periods), separately for each cultivar, with four replications. It was possible to conclude that the electrical conductivity test combining 25°C, 75 mL of deionized water and 50 seeds was sufficiently sensitive to evaluate the physiological quality of sunflower seeds.