Tratamentos pré-germinativos e avaliação do potencial fisiológico de sementes de mamona / Pre-germination treatments and physiological evaluation of seeds of castor bean
AUTOR(ES)
Rita de Cássia Mendes
DATA DE PUBLICAÇÃO
2007
RESUMO
The work was done to evaluate the effect of pre-germination treatments on seed performance of castor bean and to determine the efficiency of different tests for physiological potential evaluation of these seeds. Two assays were conducted in the Seed Research Laboratory at University Federal of Viçosa. In the first assay, five seed lots of castor bean, Al-Guarany cultivar, were submitted to the following treatments: control (untreated seeds), scarification with sandpaper, caruncle removal, tegument removal, immersion in water for 12 and 24h, caruncle removal + immersion in water for 12 and 24h, scarification with sandpaper + immersion in water for 12 and 24h, germination at 10C/7 days and at 25C/5 days, germination at 10C/7 days and at 30C/5 days, accelerated aging at 41C/48h and 100% RH. After each treatment, with exception of the germination at 10C, the seeds were submitted to the germination test, at 25C. Countings were perfomed at 7 and 14 days after sowing. The trial was conducted in randomized completely design, with four replications. The means of treatments were compared by TuKey test at 5% probability. In the second assay, seven seed lots of AL-Guarany cultivar were submitted to the following tests: seed moisture content, standard, germination, first count, cold test (10C/7 days and 25C/5 days), seedling emergence, speed emergence index , accelerated aging (at 41C and 45C and 100% RH, for 48, 72 and 96h) and electrical conductivity (25 seeds soaked into 75 and 100mL of distilled water, at 25C, for 2, 4, 6, 8, 24, 48 and 72h). The trial was conducted in randomized completely design, with four replications. The means of treatments were compared by TuKey test at 5% probability. In general, all the pre-germination treatments contributed to increase the percentage of germination of castor bean seeds in relation to control. The most efficient treatments to speed up germination were scarification with sandpaper and caruncula or tegument removal. However, considering the practical application, the scarification can be recommended to increase the percentage and speed of seed germination. Cold test and accelerated aging (41C/72 hours) were efficient to evaluation of physiological potential of castor bean seeds, allowing classification of lots similar to seedling emergence. Electrical conductivity test was not adequate for physiological potential evaluation of these seeds.
ASSUNTO(S)
physiological potential ricinus communis germination ricinus communis germinação vigor fitotecnia
