Color, temperature and pre-soaking in seed germination of Jacaranda decurrens subs. symmetrifoliolata Farias & Proença, Bignoniaceae family

Abstract

Jacaranda decurrens subsp. symmetrifoliolata is a typical species of the Savannah environment. The tea of their roots has been largely used in the popular medicine as either a depurative of the blood or a healer of the wounds in uterus and ovaries. However, little it is known about the reproduction and agronomic characteristics of this species. This study aimed to evaluate both the percentage and rate of the germination speed in differently colored Jacaranda decurrens subsp. symmetrifoliolata under several temperatures with and without soaking. On April 2001, the seeds were collected in a characteristic Savannah area at the Areeira farm, Dourados -MS. The tests were carried out in the UFMS Seed Laboratory, during the period from May to June 2001. In the first test, the germination of the seeds exhibiting either light, medium, or dark brown colors were evaluated by using an entirely randomized experimental design with five replicates. The seeds were conditioned in a gerbox-type box, using a filter paper moistened into distilled water as substrate, and were kept at a constant temperature of 25°C. In the second test, the evaluation was performed for the alternated temperatures (20-30°C with photoperiod of 12 hours day/night) and the constant ones (20 and 25°C under light, with constant photoperiod), with and without soaking into water for 24 hours. The treatments were arranged in a 3x2 factorial scheme, on an entirely randomized design with four replicates. At the second day from sowing, the percentage and rate of the germination speed were evaluated. The colours of the seeds showed no significant influence upon germination, which averaged 74.15%. The light brown seeds showed a faster germination. No significant interactions occurred between the temperatures and soaking. At seven days after sowing, the seeds began to germinate (6.25% germination), when under the alternate temperatures of 20-30°C and the constant temperature of 25°C. At these temperatures, the germination percentages higher than 85% were observed at 42 days. According to the results, it was concluded that neither the separation of the seeds by colour nor the use of pre-soaking is necessary.