The period of viability of cupiúva seed (Tapirira guianensis Aublet.) is very short which hampers its use by nurseries. Due to the scarcity of research on the critical moisture content beyond which seeds would not germinate, this study was carried out to evaluate the physiological quality of seeds of T. guianensis submitted to different periods of drying conditions of 40 °C in an oven (0, 3, 6, 9, 12, 15, 18, 21 and 24 hours).The experimental design was completely randomized and data were submitted to analysis of variance and regression. The evaluation of the treatment effects was based on the determination of moisture content, % of seed germination and vigor (first count and germination speed; seedling length and seedling dry weight). The initial moisture content was 36%, which registered the highest germination percentage (97%). This was reduced with the increase of drying periods, reaching only 38% after 9 hours of drying and subsequent even more drastic reduction. As for the germination speed, the highest value (2.93) occurred in the zero period of drying, the same occurring with the length and dry weight of seedlings, which were reduced drastically with increasing periods of drying. The T. guianensis seeds are recalcitrant, which lose their viability and vigor as their moisture content is reduced, the critical level of moisture below which there is total loss of viability is 16%.
cupiúva; recalcitrant seeds; native fruitful; moisture content
