Temperatura para germinação e formação de plântulas de Copaifera multijuga Hayne em cinco anos de frutificação

Abstract

Copaifera multijuga (Fabaceae ) is an emergent tree of Amazonian terra firme forest with multiple use. The objective of this study was to provide information on the temperature for germination and normal seedling development of a typical species with restricted distribution in the tropics and to support the seed trade. For despite the high economic interest of its timber and the medicinal oil extracted from the trunk, forest plantations are rare. Years with abundant fruiting occur at longer intervals and in this study the seeds collected in 1991, 2011 and 2013 of a natural population in the Manaus -AM region were compared. An estimate of individual seed moisture by an acoustic test (distinction between " pling " and "plong") was assessed and verified the relationship between seed moisture after collection and germination. Constant temperatures between 5 and 40 ° C were tested on the root protrusion and normal seedling development. After 65 days the non-germinated seeds were transferred to 35 ° C. It was possible to correlate rainfall with seed moisture at harvest in the three years of fruiting. The possibility of distinguishing by an acoustic test the dry seeds (" pling " with mean seed moisture 23.4 ± 6.5 %) from the moist seeds ("plong ": 41.4 ± 9.2 %) was confirmed. There was a positive relationship between seed moisture at harvest with the protrusion speed of the root in germination tests. Among the conditions studied, the most suitable temperature for germination was 30 °C, which resulted in the highest percentage and rate of germination, and can be considered as optimal. The temperature range of root protrusion was larger than of normal seedling development, with a minimum temperature between 10 and 15 ° C and 15 to 20 ° C, respectively. The maximum temperature for both criteria was above 35 ° C. The seeds did not tolerate cooling below 15 °C for 2 months, however the dryer seeds ("pling") were less sensitive than the seeds with higher moisture at harvest ("plong"). C. multijuga seeds showed typical thermal sensitivity for a tropical species. The weather conditions at the time of fruiting may influence sensitivity to refrigeration and germination.