Dormancy in native fruit seeds of the Brazilian South Region

Abstract

The aim of the present study was to investigate whether seeds from six native fruit species ofthe South Brazilian regionhad any type of dormancy, as well as, to verify if they havephotoblastism. The work was carried out at the Plant Physiology Laboratoryofthe Federal Technological University of Paraná –Câmpus Dois Vizinhos, Paraná State, Brazil. The influence of photoperiod factors and techniques for overcoming dormancy were tested on the germination of Eugenia uniflora L.(Surinan cherry), Plinia peruviana(native jabuticaba), Plinia cauliflora(hybrid jabuticaba), Eugenia involucrataDC. (Rio Grande cherry), Myrcianthes pungens(guabiju) and Campomanesia guazumifolia(sete capoteiro). The seeds were exposed in a condition of total darkness or photoperiod of 24 hours, being the levels of one of factors tested. The techniques for breaking dormancy tested werethe immersion in gibberellic acid solution (200 mg L-1); stratification at 5°C for 30 days; immersion in water at room temperature for 24 hours; immersion in hot water (80°C) for five minutes; immersion in sulfuric acid solution (96%) for five minutes; and manual physical scarification with 120 grit sandpaper. The seeds were also tested without using any technique, making up the controlstreatments with or without light. The experimental design was completely randomized, in a 2 x 7 factorial scheme (luminosity x treatment for breaking dormancy), with four replications of 100 seeds. After 60 days, germination (%), percentage of accumulated germination, germination speed index and average germination time were analyzed. The seeds of most of the studied native species do not present dormancy or the effect of photoblastism, except for “sete capoteiro”seedswho are supposed to have morphophysiological dormancy, with negative photoblastism. The use of hot water or sulfuric acid in the seeds of native fruit trees is not recommended.