Respiração de embriões recalcitrantes de Inga vera Willd. subsp. affinis (DC.) T.D. Pennington sob diferentes temperaturas, potenciais osmóticos e aplicação de ABA

Abstract

RESUMO O elevado metabolismo de sementes sensíveis à dessecação (recalcitrantes) de Inga vera Willd. subsp. affinis (DC.) T.D.Pennington é um dos principais fatores que dificultam a manutenção da viabilidade fisiológica das sementes durante o armazenamento. Devido à falta de informações sobre o metabolismo respiratório dessas sementes em diferentes condições de estresse, este estudo teve como objetivo determinar as taxas de respiração de embriões com diferentes conteúdos de água e em diferentes temperaturas após a aplicação dos tratamentos com ABA e PEG. Os resultados mostraram altos níveis de respiração e presença de reações oxidativas. O ABA mostrou poucos efeitos, mas a respiração e os processos oxidativos foram diminuídos pela secagem leve e pelo tratamento com PEG. Portanto, a redução da temperatura de armazenamento é eficiente na redução do metabolismo, permitindo ampliar o armazenamento, mas a escolha do estádio de maturação é decisiva para melhor conservar os embriões de Inga vera.

Respiratory rates and freezing tolerance of embryos of Inga vera Willd. subsp. affinis (DC.) T.D. Penn. from different regions

“…Therefore, these (PIR) are embryos at a more advanced stage of maturation than those of SAP and PAR and are very similar to those of RIB. Thus, it was clear that environmental conditions had an important effect on the maturation process of Inga vera seeds until the moment of dispersion, as reported in previous works, also for other species of the same genus (Bonjovani and Barbedo, 2020;Mata et al, 2013).…”

“…The results of the initial characterization showed that, although all the fruits had been collected when they were ripe, their embryos showed maturation differences: those of RIB, for example, were closer to physiological maturity than the others, because: a) although the embryos from all regions had very high water content, above 50%, typical for species of the genus Inga (Mata et al, 2013;Schulz et al, 2014), those from RIB had the lowest water potential. This result indicates more binding sites, therefore a better structured matrix (Vertucci and Farrant, 1995); b) the embryos accumulated more dry weight (Marcos-Filho, 2015); c) they had a lower respiration rate, indicating that they were among more mature embryos (the more mature, the lower the respiratory rate, Araujo and Barbedo, 2017) and embryos that had already started germination (the more advanced in germination, the higher the respiratory rates, Hell et al, 2019); d) they had the longest mean germination time, indicating that they had not started germination before harvest, which is relatively common for embryos of this species (Andreo et al, 2006;Bonjovani and Barbedo, 2020).…”

“…Water content and dry weight content were determined gravimetrically by the oven method at 103 °C for seventeen hours, with results expressed on a wet basis (Brasil, 2009). Water potential (MPa) was measured in a WP4 potentiometer (Decagon Devices, Pullman), based on the dew point temperature of the air in equilibrium with the tested sample (Bonjovani and Barbedo, 2014). The germination test was carried out on a paper roll, in BOD chambers, model 347 CD (Fanem, São Paulo), at 25 °C and continuous light.…”

Atmosphere modification system for respiration analysis of recalcitrant seeds during storage

“…Pennington embryos were obtained at Villa-Lobos Park (23°32' S; 46°43' W), São Paulo, SP, Brazil. Fruits were harvested manually when ripe, as described by Bonjovani and Barbedo (2020) and then taken to the Seed Analysis Laboratory, where their diaspores (embryos and sarcotesta) were extracted and washed. The sarcotesta was removed and the embryos were then washed under running water to remove any residues of sugars, which could compromise their storage.…”

“…Thus, the objective of this study was to develop methods that allow the generation of MAs in a standardizable way, thus, allowing analyzing the reduction of respiratory metabolism of recalcitrant seeds. Subsequently, recalcitrant embryos of Inga vera, considered to be among the most recalcitrant known (Bonjovani and Barbedo, 2020;Pereira et al, 2020), were used as a model for controlling this respiration, seeking atmospheres that reduce the respiratory rates of these embryos during storage.…”