Estudos da quebra de dormência da semente do umbuzeiro (Spondia tubenosa, Arr. Câmara)

Abstract

Laboratory studies were conducted in order to break the seed dormancy of Umbuzeiro (Spondiah tubeoha Arr. Câmara) and uniformize their emergence. Firstly, a set of observations on water absorption was carried in two lots of pits, one of which was ruminated by goats, and a11 of the pits were submitted to a sloping cut at their distal face. Another set of observations was done in intact pits, ruminated or not by goats. The results indicated that the Umbuzeiro pits absorved water, even if they were ruminated or not; the sloping cut was efficient in breaking the dormancy caused by mechanical resistance of the endocarp. A third experiment consisted in soaking ruminated and cut pits in gibberellic acid (GA3) solutions under the following concentrations: 0.2; 0.4;0.6; 0.8; and 1.0 μM. It was verified that GA3, under the above concentrations, was ineffective in altering the percentage of emergence of the seedlings, although the seedlings originated from pits, treated with GA3 resulted to be more vigorous. On a fourth experiment, it was observed the influence of the size of non-ruminated and cut pits in the speed of emergence and in the seedling vigor. The results showed that small pits presented faster seedling emergence, but the medium and large ones originated more vigorous seedlings.