Isoenzyme activity in maize hybrid seeds harvested with different moisture contents and treated

Abstract

-The analysis of isoenzyme activity is an important monitoring and characterization tool of the physiological quality of seeds and to understand the deterioration. The purpose of this work was to study the isoenzyme expression allied to the quality of maize hybrid seeds harvested at different moisture levels and subjected to chemical treatment. A completely randomized experimental design was used with four replicates, in a 3x2 factorial arrangement with three moisture levels (45%, 40% and 35%), and two forms of seeds tillage (with and without treatment). Seeds from maize hybrids, semi-hard BM 810 and dented BM 3061, were used. Seeds were manually gathered on ears. Chemical treatment was performed with commercial products Maxin ® + K-obiol ® + Actellic ® . Seed quality was assessed by moisture test, incidence of mechanicals damage, first count of germination, germination, emergence, emergence speed index, mean emergence time, accelerated aging, and electrical conductivity. Isoenzyme expressions were assessed by means of the systems superoxide dismutase (SOD), catalase (CAT), esterase (EST), alcohol dehydrogenase (ADH), malate dehydrogenase (MDH), peroxidase (PO) and α-amilase. Isoenzyme expressions are different, depending on moisture levels at harvest, the hybrid maize and seeds quality. Seeds treatment does not interfere in their isoenzymes expression.Index terms: Zea mays, isoenzyme expression, physiological quality.Atividade isoenzimática em sementes de milho híbridos colhidas com diferentes teores de água e tratadas RESUMO -A análise da atividade enzimática é uma importante ferramenta no monitoramento e caracterização da qualidade fisiológica de sementes e no entendimento da deterioração. Objetivou-se com este trabalho estudar a expressão de isoenzimas aliada a qualidade de sementes de milho híbrido colhidas com diferentes teores de água e submetidas ao tratamento químico. O delineamento utilizado foi o inteiramente casualizado, com quatro repetições, em esquema fatorial 3x2, sendo três teores de água (45%, 40% e 35%), e duas formas de manejo das sementes (tratadas e não tratadas). Foram utilizadas sementes de milho dos híbridos: BM 810, semiduro e BM 3061, dentado, colhidas manualmente em espigas. O tratamento químico foi realizado com os produtos comerciais Maxin ® + K-obiol ® + Actellic ® . A qualidade das sementes foi avaliada pelos testes de umidade, incidência de danos mecânicos, primeira contagem de germinação, germinação, emergência, índice de velocidade de emergência, tempo médio de emergência, envelhecimento acelerado e condutividade elétrica. As expressões isoenzimáticas foram avaliadas por meio dos sistemas superóxido dismutase (SOD), catalase (CAT), esterase (EST), álcool desidrogenase (ADH), malato desidrogenase (MDH), peroxidase (PO) e α-amilase. A expressão de isoenzimas é divergente dependendo do teor de água na colheita, do híbrido e da qualidade das sementes. O tratamento de sementes não interfere na expressão das isoenzimas.Termos para indexação: Zea mays, expressão isoenzimática...

Biochemical changes and physiological quality of corn seeds subjected to different chemical treatments and storage times

“…In general, the expression of esterase did not change in any of the hybrids under study (Figure 2). Although an increased production of esterase was reported in corn seeds in an advanced state of deterioration (Ferreira et al, 2015), significant changes in its expression behavior are more likely in seeds with high lipid content, as the enzyme participates in ester hydrolysis and lipid metabolism (Carvalho et al, 2014). The relationship of esterase with the deterioration of seeds is explained by its action on the lipid layers, causing membrane destabilization, and contributing to the deteriorative process (Vieira et al, 2006).…”

Temperatures and periods of drying delay and quality of corn seeds harvested on the ears

“…Together, they account for the deterioration intensity (Carvalho and Nakagawa, 2012;Shaban, 2013). Ferreira et al (2015) investigated corn seeds harvested with 30%, 40% and 45% moisture contents. They noticed a more substantial expression of enzymes related to aerobic and anaerobic respiration (malate dehydrogenase -MDH, and alcohol dehydrogenase -ADH, respectively) in those seeds bearing higher water content.…”

Lignin and Activity Enzymatic in Susceptibility to Weathering Damage on Soybean Seeds

“…In the soybean production process, it is recommended to harvest at the closest possible moment of physiological maturity. According to Ferreira et al (2015), at the stage near physiological maturity, seeds have a high level of vigor and high water content and these facts involve the improvement of post-harvest techniques.…”