Do scarification and seed soaking periods promote maximum vigor in seedlings of Hymenaea courbaril?

Oscar José Smiderle,Aline Das Graças Souza

doi:10.1590/2317-1545v43254481

Oscar José Smiderle, Aline Das Graças Souza

Open Access

https://doi.org/10.1590/2317-1545v43254481

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Abstract

Abstract: The aim of this study was to establish a methodology to determine physiological vigor in small and large seeds of Hymenaea courbaril L. non-scarified seeds and scarified by the electrical conductivity test and period of seed soaking in water aiming at maximum capacity of emergence and seedling vigor. The design was completely randomized, in a 2 x 2 x 5 factorial scheme (two classes of seed mass, non-scarified seeds and scarified and five periods of soaking in water), with 10 replicates of 10 seeds each. The variables evaluated were electrical conductivity (μS cm-1.g-1), emergence speed (index), seedling emergence (%) and mean time of emergence (days), obtained by means of daily counts until stabilization in the values. Maximum vigor of Hymenaea courbaril seedlings is obtained with large seeds subjected to scarification and soaked in water for six hours. Water content of 18.7% in large seeds of Hymenaea courbaril scarified promotes the production of 100% of vigorous seedlings. Small and large seeds of Hymenaea courbaril non-scarified seeds and scarified, soaked for six hours, had shorter mean time for seedling emergence. Water content of 20.6% in small seeds of Hymenaea courbaril scarified promotes 100% seedling emergence. The electrical conductivity test applied to Hymenaea courbaril seeds can be adopted to determine seed vigor, showing speed in the obtaining of results and ease of execution.

Highlights

Increased demand for native seeds for ecological restoration and rehabilitation has stood out in the large global industry of seed supply and sale (Smiderle et al, 2021)
The mass of mechanically scarified small and large seeds of H. courbaril increased after 12 hours compared to nonscarified seeds (Figure 1)
In large seeds of H. courbaril scarified, that the final mass, after 12 hours of soaking, showed a gain in the water content of 6.27% compared to the initial mass

Summary

Introduction

Increased demand for native seeds for ecological restoration and rehabilitation has stood out in the large global industry of seed supply and sale (Smiderle et al, 2021). Research with native forest seeds is essential for obtaining seedlings of high quality and in quantities that meet the demands of the forestry sector segments (Leão et al, 2016), as seed propagation is the main form of dissemination of species and the study of seed technology and production becomes of great relevance in the process of management, conservation and genetic improvement (Menegatti et al, 2019). Hymenaea courbaril L. seeds, when mature, have dormancy due to the impermeability of their coat to water, so it is necessary to apply a treatment to overcome dormancy, and mechanical and physiological scarifications are forms that enable the emergence of seedlings (Paixão et al, 2019). The emergence test is used to evaluate the physiological quality of seeds, making it possible to know the emergence potential of seedlings under favorable conditions (Nascimento et al, 2019). It is important to evaluate the vigor of the seeds to complement and elucidate the information provided by the physiological tests based on vigor

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