SuperaÃÃo de dormÃncia de diÃsporos de cajazeira (Spondias mombin L.). / Hog plum tree (Spondias mombin L.)endocarps dormancy eakage.




The hog plum tree appear as one most promising fruit tree for the cultivation in commercial scale, due to its excellent adaptation to the agro-ecological conditions of the Brazilian Northeaste, especially, under semi-arid ecosystem and its high socioeconomic potential. Therefore, it is necessary its domestication, which is quite hindered due to propagation problems, because its seeds present an accentuated dormancy of reason(s) still unknown(s) and whose breaking methods are quite questioned. This research had as objective to study morph physiologic aspects of the germination, to identify the dormancy reason(s) and to develop capable methods of overcoming it, by conducing three experiments at the Seeds Analysis Laboratory - UFLA. The morph physiologic characteristics were analyzed through the tests: count of the loci number and seeds for endocarp, humidity degree, curves of soak, tetrazolium and X ray. In the first experiment were appraised the effects of endocarp physical scarification, chemical scarification with H2SO4, GA3 solution immersion and cold stratification, being carried out in a completely randomized design blocks with four replicates of 25 seeds. The second experiment had as treatments, preheating, soaking in running water and hot stratification of endocarps in different combinations disposed in completely randomized design in factorial scheme 2x2x2+1. The third experiment was installed based on the two previous experiments best results, in completely randomized design in factorial scheme 2x2x2, whose factors were: endocarp physical scarification, hot stratification (30ÂC) and GA3 solution immersion (1000 mg.L-1) combined according to treatment presence or absence. The evaluations were done by germination test, germination speed index and medium time of germination. The hog plum tree endocarp is permeable to water. Tetrazolium solution concentration at 0,5% for 24h at 30ÂC allows evaluate seed viability. The X ray radiation intensity at 60 Kvp applied to seeds for 30 seconds, allows bright visualization of internal endocarp structures. Pre-heating for five days, followed absorption in running water for 14 days and hot stratification at 30ÂC for 7 days, allowed a higher germination speed of the hog plum seeds; the endocarp physical scarification atthe area close to the embryonic axis and hot stratification at 30ÂC for seven days resulted in the best efficiency on the dormancy breakage of hog plum seeds. It was not possible to determine precisely what are the hog plum seed dormancy.


semi-Ãrido semi-arid adaptation visualization adaptaÃÃo visualizaÃÃo fitotecnia

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