Influence of Harvest, Processing, and Substrate in the Germination of <i>Dalbergia nigra</i> Seeds

Abstract

Dalbergia nigra is a Brazilian native species with relevant economic and ecological roles. Due to its indiscriminate exploration is an endangered species. Besides the great demand for seedling production, only a few aspects of D. nigra germination have been explored. Thus, this study aimed to determine how harvesting immature fruits, fruits processing, and substrate could influence Dalbergia nigra germination process. Five thousand immature, and five thousand mature fruits evenly distributed between two replicas of each of tree 3 treatments; integral fruits, fruits with edges cut, and direct seed sowing in vermiculite. Seeking to evaluate substrate influence over germination, 252 seeds were strewed in the prepared organic substrate. No fruits harvested in visually green appearance did germinate under any of treatments. Integral fruits and cut procedure presented the same time for the first germination, almost two times the amount observed to direct seeds sowing. Besides that, the germination rate was not statistically affected. We found that different substrates also influence the germination pattern, as seen to seed processing when using vermiculite as a substrate, germination starts earlier but the germination rate was not statistically affected. Harvest of Dalbergia nigra green fruits is not an adequate procedure seeking seedling production. The reduction on germination time and better seedling quality, indicate that direct seed sowing procedure is adequate seeking seedling production. Vermiculite substrate gave better results, reducing the time required to germination process. Besides that, this substrate did not affect the germination rate during this study period.

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

“…While the recalcitrant seeds are very susceptible to modifications of moisture content, reducing seed viability. When seeds are exposed to favorable germination conditions, embryo development is retaken after the imbibition process [21], [36]. It was still unknown the H. courbaril behavior [3], [5], but our data suggest that this species´ seeds are capable of long-term storage without losing their germination potential, even after 200 or 365 days after harvest.…”

“…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]. Producing regional limitations of some study findings [30].…”

Morphological integration between seeds and seedlings ofHymenaea courbaril

“…In the seedling production context, seed weight is usually a parameter to measure the seed lot quality and genetic diversity [1], [4], [9]. In addition, it is relevant, as these seeds are usually sold per kilogram [9], [41], [42].…”

“…is important to compare populations to comprehend the multiplicity and infer the remaining genetic diversity between them [9]. In general, variations between populations in seed and fruit morphometrics are expected because they are under different environmental conditions [9], [42], and evolutionary processes [38], [42]. Part of phenotypical measurements could also be due to plastic responses to heterogeneity in environmental factors [19].…”

Mechanical scarification, seed origin, and substrate influence on germination ofSamanea tubulosa

“…In general, variations between populations are expected to nondomesticated species [17]. Wild species present greater regional variations because they are under a continuous evolutionary process, and this could create great variations between populations [17], [18], [24]. Therefore, depending on the study sampling standardization, the results will be only regionally applicable [17].…”