Aspectos fisiológicos e bioquímicos da germinação de sementes de alface em diferentes temperaturas

Abstract

The objective of this work was to evaluate the electrophoretic patterns of heat-tolerant proteins and the activity of the endo-β-mannanase enzyme during lettuce seed germination, at high temperature. Seeds of eight lettuce cultivars were subjected to germination, first count, and emergence tests at two temperatures, 20 and 35°C. The index of germination speed (IVG) and the emergence rate index (IVE) were calculated. The expression of heat-tolerant proteins and of the endo-β-mannanase enzyme was also evaluated for all treatments. The experimental design was completely randomized, in a 2x8 factorial arrangement, with two temperatures and eight cultivars. The highest germination is observed at 35°C in the Everglades cultivar, considered thermotolerant. The patterns of heat-tolerant proteins in lettuce seeds present specific bands in the Everglades cultivar, at 35°C. The activity of the endo-β-mannanase enzyme is higher in the Everglades cultivar, at this temperature. This cultivar has potential for use in lettuce breeding programs aiming for tolerance to high temperatures during germination.