Evaluation of Harvesting and Seed Dormancy Overcoming Techniques in <i>Hymenaea courbaril </i>Germination

Abstract

Hymenaea courbaril is an endangered Brazilian native species. Recently, this species has been used on reforestation programs. So, production techniques that propitiate faster germination are very important. Although, seed dormancy, which could hamper the seedling production process, is not extensively recognized. Thus, this study focused on evaluating the influence of early harvest technique, scarification and pre-imbibition techniques to overcome H. courbaril seed dormancy in two steps. First, evaluating green fruits harvest could influence the germination process, 137 visually healthy seeds from green fruits and 400 seeds from mature fruits were selected. Seeds from green fruits presented similar results to seeds from mature fruits. Probably due to the natural seed tegument rupture. After, the influence of mechanical scarification, pre-imbibition and the combination of both methods were measured. All studied processing methods did not affect significantly any of the germination measurement parameters. Mechanical scarification exhibits similar responses as previous studies showed when using acid scarification. The technique of harvesting green fruits from the treetop seems to be applicable to commercial seedling production. While none of the studied treatments promoted significantly benefits to germination at any of the indexes.

Germination of<em> Hymenaea courbaril</em>: Storage Behavior, Origin, and Substrate

“…The other analyzed germination indeces did not present statistical significance. Previous variations in the uncertainty index were also observed for H. courbaril according to the harvesting method [31]. Several environmental conditions could influence the process of seed soaking [32].…”

“…Other authors indicate a wider range of germination rates, from 89.5% [37] to 60% [38]. Recent studies, using similar conditions [31], presented comparable values of germination rate, around 50%. It is expected to find variations in seedling emergence and germination potential between seed lots since these species are continuously submitted to the evolutionary process of the natural environment [30], [36].…”

“…Germination indexes are important to physiologists, seed technologists, and also for ecologists because it is possible to predict the species capacity of their harvest seed to spread germination through time [39]. From this perspective, the synchrony on the germination process is very important since homogeneous germination requires less time to keep a seed lot in the greenhouse or BOD chamber [31]. Posterior seed development stages and further production steps could be done in sequence since germination occurs at concentered periods [32].…”