Efeito da secagem na qualidade fisiológica de sementes de puxuri (Licaria puchury-major (Mart.) Kosterm.)

Abstract

Drying is a pre-storage method that maintains the physiological quality of the seeds by reducing the water content, enabling the storage of species for an indefinite period. Among the purposes of seed conservation are the formation of commercial plantations, native forest gene banks and reforestation. The species used in this work was Licaria puchury-major (Mart.) Kosterm., an aromatic species used in agroforestry systems, consortia, familyagriculture, cooking, carpentry, civil construction, paper manufacturing, perfumery, chemical industry and medicine. This work was carried out with the objective of evaluating the effect of drying on the physiological quality of puxuri seeds. The experiment was carried out at the Fruticulture Laboratory of Embrapa Amazônia Oriental, in Belém/PA. The experimental design was completely randomized, with four treatments and four replications of 25 seeds per treatment. The determinations of water content were obtained by the oven method at 105ºC, for 24 hours, with four seeds per repetition. After obtaining the first treatment (seeds just harvested) the seeds were placed in an environment with a temperature of 23º C and 50% relative humidity for 24 hours, obtaining the other treatments T2 - 47.7% of water; T3 - 39.1% water; T4 - 29.9% water. The variables evaluated were: Days to start emergence (DIE), emergence (E), emergence speed index (IVE), germination (G) and abnormal seedlings (PA). Treatment means were compared by Tukey's test (p<0.05). In the results, the drying curve decreased linearly, with a variation of 99% and the first two treatments (T1 - 50.3% of water and T2 - 47.7% of water) did not differ significantly from each other due to little difference in content of water. While the last two treatments (T3 - 39.1% of water and T4 - 29.9% of water) obtained a significant difference in the emergence curve. At 39.1% of water content, the seeds showed changes in physiological quality, such as an increase in the days to start emergence (DIE) and a decrease in the emergence speed index (IVE). At 29.9% water content (TA) there was a 62% reduction in seed germination, below this content the seeds lose viability. It is concluded that the puxuri seeds are recalcitrant and present satisfactory results, in relation to the physiological quality, when in contents of up to 47.7% of water. Due to sensitivity to drying, sowing soon after collection is recommended.