Germination of seeds of Caatinga native tree species at different temperatures

Abstract

Native tree species of the Caatinga of northeastern Brazil  have great economic importance due to their multiple uses, such as for the production of honey , fodder , timber, energy, ornamental and herbal products , resulting in serious problems for the most used species To obtain information about the seed behavior of native tree species of the Caatinga at different temperatures , this study was conducted at Embrapa Semiarid , Petrolina , Pernambuco , Brazil . Seeds Sideroxylon obtusifolium (Roem & Schult. ) Myracrodruon urundeuva (Fr. All.), Amburana cearensis (All.) and Schinopsis brasiliensis ( Engel. ) germinated on paper rolls at 20, 25, 30and 35°C in a completely randomized design with 5 replications of 10 seeds for S. obtusifolium , S. brasiliensis and A. cearensis and five replicates of 50 seeds of M. urundeuva . Germination was evaluated every 2 days, obtaining the germination curve, final germination ( % ) and germination speed index(GSI). Seeds of S. obtusifolium and M. urundeuva had higher germination percentage and speed at 20°C. Seeds of S. brasiliensis had higher germination, by about 50 %, at 25 and 30°C and higher GSI at 30°C. Among the seeds of A. cearensis the highest germination (96 %) was observed at 30°C, however, the GSI was higher at 35°C. These results indicate that each species has specific optimum temperature for the germination process.