DORMANCY IN NATIVE FRUITS SEEDS OF THE BRAZILIAN SOUTH REGION

Abstract

The aim of the present study was to investigate whether seeds from six fruit trees native of the South Brazilian region had any type of dormancy, as well as, to verify the existence or not of photoblastism in them. The work was carried out at the Plant Physiology Laboratory, at the Federal Technological University of Paraná - Dois Vizinhos câmpus. The influence of photoperiod factors and techniques for overcoming dormancy were tested on the germination of Eugenia uniflora L. (Surinan cherry tree), Plinia trunciflora (steamed jabuticaba tree), Plinia cauliflora (hybrid jabuticaba tree), Eugenia involucrata DC. (Rio Grande cherry tree), Myrcianthes pungens (“guabijú” tree) and Campomanesia guazumifolia (“sete capoteiro”). The treatments were the interactions of these two factors levels. The seeds were exposed in a condition of total darkness or photoperiod of 24 hours. Techniques of immersion in gibberellic acid solution (200 mg L^-1) were also submitted; stratification at 5ºC for 30 days; immersion in water at room temperature for 24 hours; immersion in hot water (80 ºC) 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 control treatment. 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” who 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.