Avaliação de testes de vigor e germinação de sementes de gergelim em função da temperatura e do potencial osmótico

Abstract

The physiological potential of seeds, which is determined by germination and vigor, is primarily responsible for the performance of seeds in the field. Thus, the present study aimed to assess the germination behavior as a function of temperature and water stress and salinity, as well as studying different vigor in evaluating the physiological quality of two cultivars of sesame (Sesamum indicum L.). It had been used sesame seeds, the G2 and G4 cultivars, from Embrapa Cotton, in the city of Campina Grande, Paraíba. Evaluations were performed at the Laboratory of Seed Analysis Centre of Agricultural Sciences UFAL. Was initially conducted a germination test, then evaluated the effect of sesame seeds through the tests of the first count, seedling length and dry matter, which was performed under controlled light, temperature and humidity. Soon after tests were performed emergency first count of seedlings, seedling length and dry matter, and those tests were performed under uncontrolled conditions. Was also performed accelerated aging test temperature of 41 ° C in periods of 48 and 72 hours. Was also carried out electrical conductivity using the soaking periods 2, 6, 10, 24, 30 and 48 hours, readings were taken in the conductivity meter and the results expressed in μS.cm-1.g-1. We also evaluated the germination behavior of sesame seeds before different temperatures (15 ° C, 25 ° C, 30 ° C, 40 ° C, 45 ° C and alternating 20-30 ° C), as well as the physiological performance in relation to environments with limited water environments and salinized, by water stress (PEG 6000) and salt (NaCl solutions), respectively. Temperatures of 15 C and 45 ° C inhibited the germination of sesame seeds, the temperatures of 25 º C and 30 ° C produced satisfactory results; The sesame showed low tolerance to drought and saline with reduced germination from the osmotic potential -0.2 MPa; The vigor tests studied may be promising alternatives for assessing the effect of sesame seeds, but no need for additional studies to determine the procedures best suited to your driving.