Biometry and effect of temperature and of seeds size on the protrusion of cotyledonary petiole of carnauba

Abstract

This work aimed to evaluate the biometry of carnauba seeds and the effect of temperature and seeds size on the protrusion of cotyledonary petiole. It was realized the biometric analysis with a sample of 100 seeds, evaluating length and diameter, what allowed to classify the seeds in three diameter classes. It was used a completely randomized design in a factorial arrangement 4 x 4: four seeds sizes (small - Φ < 12.42 mm, medium - 12.42 mm < Φ < 14.24 mm, large - Φ > 14.24 mm and mixture - seeds that were not classified) and four temperatures (20, 25 and 30 °C and environmental temperature - 28.8 °C). Were used four replications of 25 seeds per treatment and each experimental unit was packed in recipients containing 250 mL of water, maintained under different temperatures, realizing daily counting of the seeds that presented the protrusion of the cotyledonary petiole. The results allowed the conclusion that the length and the diameter of the carnauba seeds analyzed present an asymmetric behavior to the left. Under the temperatures of 20 and 25 ºC occurred the highest percentages of protrusion of cotyledonary petiole in all the seeds sizes, except for the large seeds, that expressed the best result only under 25 ºC. Seed of sizes medium, large and mixture presented highest protrusion speed. The temperature of 25 ºC is the one that promotes the highest protrusion speed. When maintained under 20 ºC, the seeds took 32 days to obtain maximum protrusion of the cotyledonary petiole.