Avaliação do potencial fisiológico, métodos de condicionamento e desempenho de sementes de couve-flor (Brassica oleracea L. var. botrytis) durante o armazenamento e em campo / Evaluation of the physiological potential, priming methods and performance of cauliflower (Brassica oleracea L. var. botrytis) seedlots

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The objectives of this research were to identify reliable methods to evaluate the physiological potential of cauliflower seeds, verify the relationship between seed physiological potential and field performance, as well as to define a suitable procedure for seed priming and identify efficient drying methods to avoid the possible reversion of beneficial priming effects during storage. The study was conducted in four steps using seed lots of cultivars Sharon and Teresópolis Gigante. The first step comprised the selection of procedures for seed vigor assessment by controlled deterioration, accelerated aging (with and without saline solution), electrical conductivity and potassium leachate tests. On the second step, was evaluated the relation of vigor tests results, seedling emergence in greenhouse and field plant performance. On the third step, were studied the rate of water absorption by seeds and techniques for hydropriming and osmopriming were studied. Finally, the fourth step included hydropriming, drying and seed storage under normal laboratory conditions and controlled conditions (20ºC and 50% relative humidity). Results showed that he traditional accelerated aging test at 41ºC/48 h, accelerated aging with saturated solution of NaCl, at 45ºC/72 h, and controlled deterioration (seeds with initial moisture content of 20% or 22%, at 45ºC/24 h) tests were sensitive to differences in the physiological potential of cauliflower seeds. The combination 50 seeds/75ml water/4h imbibition during the electrical conductivity test and 25 seeds/50ml water/ 30 minutes imbibition for the leachate test detected differences of seed vigor levels. The test results of accelerated aging or controlled deterioration must be used together with those achieved in the electrical conductivity or the potassium leachate tests, so that one can identify the lots likely to present a distinguished behavior of plants in the field. Seed vigor level affects the initial development of plants only when differences among the physiological potential of lots are sufficiently wide, but however, these possible effects do not persist over time and the final development of plants and yield are not affected. The hydropriming of seeds between four and six sheets of paper towel to reach a moisture content close to the primary root protrusion is efficient for cauliflower seeds. Rapid drying or thermal shock followed by rapid drying are efficient methods to keep the beneficial hydropriming effect for cauliflower seeds. Storage under controlled conditions (20ºC and 50% relative humidity) allows to keep priming beneficial effects up to four months.

ASSUNTO(S)

sementes vigor vigor seeds couve-flor plant physiology cauliflower fisiologia vegetal

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