Ex situ initial seedling development of Hymenaea courbaril L. (Fabaceae): a crucial phase to preserve the species

Abstract

Hymenaea courbaril L. is an important Neotropical species, with low population density, restricted to fragments of semideciduous forests, with low mortality and low recruitment. Thus, some questions guided the goals of this paper including the capacity of stored seeds to form normal seedlings. Seeds collected from ten mother plants in the Brazilian Cerrado region and stored during three years were mechanically scarified, sown and analyzed during 43 days. Intraspecific variability was observed for water content, seed biometry, and emergence process. The seedling emergence varied from 19 to 92%. Nine phases of development were observed. About 91% of the seedlings reached their complete autotrophy and this represents the success of the sample; the rest of the seedlings presented atypical morphology. This means that it is possible to store the seeds with the purpose of obtaining seedlings for ex situ cultivation. The great consumption of the cotyledon reserves occurred in the period that marks the alignment of cotyledons with hypocotyls (phases 1 to 4). For this species, if the seeds are scarified, the first 40 days after sowing are essential for the seedling establishment. After this time, the cotyledons fall signing a good point of reference for restoration projects because it indicates that the young plant is autonomous.

Constraints on tree seedling establishment after fires: passing the germination bottlenecks

“…Kielmeyera coriacea seedlings have cotyledons that are twice as heavy as those of Q. parviflora, with a larger store of nutrients and larger photosynthetic area (Kidson & Westoby 2000). The different growth strategies may be related to their competitive strategies for light and/or nutrient availability (Grisi et al 2019). The secondary roots help anchor the seedling in the soil and may prevent laminar erosion resulting from the first rains, which can expose roots and lead to seedling death from water stress in the subsequent days without rain (Silva & Castro 1989).…”

“…The different growth strategies may be related to their competitive strategies for light and/or nutrient availability (Grisi et al . 2019). The secondary roots help anchor the seedling in the soil and may prevent laminar erosion resulting from the first rains, which can expose roots and lead to seedling death from water stress in the subsequent days without rain (Silva & Castro 1989).…”