Bioestimulante no potencial fisiológico de sementes da alface

Abstract

Belonging to the Asteraceae family, lettuce (Lactuca sativa L.) is a vegetable widely consumed and cultivated globally, with great socioeconomic importance. With the growing demand for this vegetable, techniques that accelerate production have gained prominence. Therefore, soaking seeds in biostimulants plays a fundamental role, as it can accelerate, stimulate and standardize the germination process. Therefore, the objective of the present work was to evaluate the physiological potential of lettuce seeds subjected to imbibition at different periods and doses of the biostimulant Stimulate®. The work was carried out at the Phytotechnics Laboratory, belonging to the Campus of Engineering and Agricultural Sciences of the Federal University of Alagoas, located in the city of Rio Largo - AL. Seeds of curly lettuce of the Moana variety from the Isla Sementes LTDA brand were studied. A completely randomized design (5 x 2 factorial scheme), doses of the biostimulant Stimulate® (0, 4, 8, 12 and 16 mL.L−1) and seed imbibition times (8 and 16 hours) were used. The design included 10 treatments, with 4 replicates of 25 seeds each, totaling 40 experimental plots. Soon after, the seeds were placed between paper in an equidistant manner in plastic gerbox-type boxes lined with blotting paper, which was moistened with distilled water equivalent to 2.5 times the weight of the dry paper. The material was then stored in a Biochemical Oxygen Demand (B.O.D.) germination chamber regulated at a constant temperature of 20 °C. Counts were carried out at the same time from the fourth day and finished on the seventh day. The data were subjected to analysis of variance and the means compared using the Tukey test at 5% probability. The analyses were performed with the aid of SISVAR 5.8 software. For germination, the results showed that there was an influence of the periods and doses of biostimulant when compared to the control (0 mL.L-1). For the first germination count, germination speed index and average germination time, the dose of 4 mL.L-1 for 8 hours of imbibition provided the best result for these variables. As for the average germination time, the 16-hour period did not present a statistical difference between the doses. Germination uniformity was favored at a dose of 8 mL.L-1 in both imbibition periods, as observed for the germination synchrony index. For seedling length, the dose of 4 mL.L-1 for 8 hours of imbibition resulted in the greatest length. For the dry mass of seedlings, all doses of biostimulant in the 8-hour period favored the accumulation of biomass, except for the control, which differed statistically from the others. Thus, it was concluded that the biostimulant dose of 4 mL.L−1, with soaking for 8 hours, enhanced the germination and vigor of lettuce seeds.