Activities of α-galactosidase and polygalacturonase during hydration of Dalbergia nigra ((Vell.) Fr All. ex Benth.) seeds at different temperatures

Abstract

-Germination is a process that begins with seed water uptake, stimulating enzyme synthesis or activating enzymes already present. The objective of this study was to evaluate variations in monosaccharide reserves and the activities of the α-galactosidase and polygalacturonase enzymes during the hydration of two lots of Dalbergia nigra (Bahia Rosewood) seeds. Seeds from different origins constituted the two lots I and II, classified as high and low vigor, respectively. Both lots were placed in desiccators with a high relative humidity to hydrate and at 15 and 25 °C until levels of 10, 15, 20 and 25% moisture levels in seeds were reached. The seed cotyledons were analyzed for the quantity of monosaccharides and enzyme activity. The control had higher concentrations of xylose and rhamnose, which decreased during hydration until the 15% level was reached, after which concentrations increased again in both lots. Lot I, with a superior quality, showed higher glucose synthesis and degradation during seed hydration. Both enzymes were pre-existing since activity was already present in the seeds without imbibition. The polygalacturonase enzyme increased and the α-galactosidase enzyme remained relatively constant during seed hydration.Index terms: imbibition, Bahia Rosewood, biochemical modifications, monosaccharides.Atividades de α-galactosidase e poligalacturonase durante a hidratação de sementes de Dalbergia nigra ((Vell.) Fr. All. ex Benth.) sob diferentes temperaturas RESUMO -A germinação é um processo que se inicia com a absorção de água pelas sementes, estimulando a síntese de enzimas ou ativação daquelas pré-existentes. O objetivo deste trabalho foi estudar as variações nas reservas de monossacarídeos e atividades das enzimas α-galactosidase e poligalacturonase durante a hidratação de sementes de dois lotes de Dalbergia nigra (jacarandá-da-Bahia). Para tanto, sementes de duas procedências constituíram os lotes I e II, classificados como de alto e baixo vigor, respectivamente. Os lotes foram colocados para hidratar em dessecadores com alta umidade relativa nas temperaturas de 15 e 25 °C até atingirem os níveis de hidratação de 10, 15, 20 e 25% de umidade nas sementes. Os teores de monossacarídeos e as atividades das enzimas foram analisados nos cotilédones das sementes. Os teores de ramnose e xilose apresentaram valores superiores na testemunha, com redução durante a hidratação até 15%, momento a partir do qual aumentaram novamente, em ambos os lotes. O lote I, de qualidade superior, possui maior síntese e degradação de glicose durante a hidratação das sementes. Ambas as enzimas mostraram ser pré-formadas, por já apresentarem atividade nas sementes sem embebição. A poligalacturonase aumentou e a α-galactosidase manteve-se relativamente constante durante a hidratação das sementes.

Micropilar and embryonic events during hydration of Melanoxylon brauna Schott seeds

“…Among these enzymes, the activity of pectin methylesterase was detected by Scheler et al (2015) in Lepidium sativum seeds, with the penetration of the radicle in the endosperm being dependent of cells cohesion loss in place, resulting from the action of the enzyme. Moreover, the growth of the embryonic axis of Dalbergia nigra seeds by polygalacturonase was observed, which facilitates expansion of the axis by effect of hydration, according to Ataíde et al (2013). Reactive oxygen species (ROS) are considered toxic molecules formed during normal metabolic functions and induced when plants are exposed to environmental stimuli (Éaux and Toledano, 2007).…”

Acid α-galactosidase is involved in D-chiro-inositol accumulation during tartary buckwheat germination

“…In germinating legume seeds, α-galactosidase plays a role in the mobilization of RFOs [20]. The characterization and cloning of α-galactosidase during germination have been studied in other plant [21][22][23]. The activity of α-galactosidase and the expression pattern of the gene especially during tartary buckwheat germination remain unknown.…”

Germinação de sementes, produção de mudas e obtenção de parâmetros relacionados ao manejo da irrigação em Physalis peruviana L.

“…Em alguns estudos é sugerido que a redução do tempo de germinação seja uma vantagem no estabelecimento das plantas (BANO et al, 2019;WAHID;SHABBIR, 2005). Quanto mais rápido a semente inicia a fase III da germinação, onde é possível visualizar a protrusão da radícula, mais rápido será o seu estabelecimento no campo e, portanto, a sua exposição a condições desfavoráveis (ATAÍDE et al, 2016;GOMES et al, 2015).…”