PRE-CHILLING AND TEMPERATURE TO THE GERMINATION OF Baccharis trimera SEEDS

Abstract

The objective of this work was to evaluate the effect of pre-chilling and temperature on the germination of Baccharis trimera seeds. B. trimera is a medicinal plant that grows spontaneously in regions with cold winter, then the seeds germination can be affected by the low temperure before and during the germination process. The seeds were collected at the locality of Laranjeiras do Sul, Paraná State, in November of 2001, and carried to the Plant Physiology Laboratory of PUCPR at São José dos Pinhais. The pre-chilling periods at the temperatures of 2 to 7° C (0, 7, 14 and 21 days), the temperature of germination test (20 and 25° C) and the test duration (7, 14 and 21 days) were studied in a randomized block design in a factorial squeme (4 x 2 x 3) with four repetitions and 100 seeds per parcel. The pre-chilling during 14 and 21 days improved the seeds germination when the temperature of 20° C was used. Without the pre-chilling the germination percentage at 25°C (53,8%) was higher than at 20° C (10,1%). A germination percentage from 53 to 58 % was obtained when the prechilling was used. There was a significant increase of the seeds germination untill 21 days of test. The germination of B. trimera seeds is viable when the temperature of test is 25°C and the pre-chilling from 14 to 21 days is necessary when the temperature is 20° C.