Taxas respiratórias de sementes de Eugenia brasiliensis Lam. (Myrtaceae) sob atmosferas modificadas

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The reduction in humidity and temperature makes it possible to prolong the storage of seeds, except for those sensitive to desiccation (recalcitrant), which therefore cannot be included in ex situ conservation banks. One way to control the metabolic activity and the movement of water into or out of the seed is to use osmotically active chemicals, such as polyethylene glycol (PEG). In this study, the effect of storage of recalcitrant seeds of Eugenia brasiliensis with water movement control in osmotic medium was evaluated. The results showed that the maintenance of these seeds at water potentials between -1 and -2 MPa allowed increasing the capacity for conserving viability in storage. They also demonstrated that the expansion of this conservation, unlike what occurs with the reduction of temperature, is not necessarily associated with the reduction of metabolic rates.

Storage of recalcitrant seeds of Eugenia brasiliensis Lam. under control of water availability

Cécel,

Barbedo

2023

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Atmosphere modification system for respiration analysis of recalcitrant seeds during storage

Manoel,

Tiné,

Guardia

et al. 2024

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The modification of atmosphere composition is a strategy to prolong the storage of organisms susceptible to senescence. Atmospheres with high levels of carbon dioxide could be applied to prolong the viability of recalcitrant seeds, which are in a constant process of deterioration due to intense metabolic activity. However, there is a need to develop methods that allow the standardized generation of these modified atmospheres to isolate the effect of low oxygen from high carbon dioxide. In this study, the generation of modified atmospheres was carried out by experiments with insufflated gas (IG) or compensated vacuum (CV), on recalcitrant Inga vera embryos as an experimental model. In IG, CO2 and N2 were uninterruptedly injected into a mixing chamber, in which the gases underwent turbulence to be homogenized and subsequently applied to the flasks where the embryos were incubated. In CV, the embryos were placed in flasks, from which a fraction of the air present inside was removed, and subsequently, the gases of interest were injected in defined fractions. The CV method proved to be more efficient and it was possible to restrict the respiratory metabolism of the Inga vera embryos by reducing respiration with the increase in carbon dioxide applied exogenously.

Storage potential of Eugenia uniflora Lam. seeds incubated in different osmotic solutions and temperatures

Gomes,

Barbedo

2024

The ex situ conservation of recalcitrant seeds has been one of the biggest challenges in seed technology. Different strategies have emerged in recent years and among these strategies, osmotic conditioning at controlled temperatures has shown excellent results. Therefore, the objective of this research was to store recalcitrant seeds of E. uniflora through osmotic conditioning in order to reduce the metabolism of these seeds and extend their storability. The seeds were stored at temperatures of 10 and 25 °C in PEG solutions at 0.0 (water), -0.5, -1.0, -1.5, and -2.0 MPa, as well as without moistening, for 3, 6, 12, and 18 months. There was a reduction in metabolism in the treatments with PEG, and seed viability was maintained after 18 months at 25 °C and -1.5 MPa.