Electrical conductivity and mineral composition of the imbibition solution of bean seeds during storage

Abstract

ABSTRATThe electrical conductivity test has been used to evaluate seed vigour in many species, especially legumes, such as peas, beans and soybeans. The objective of this research was to evaluate the effect of temperature and storage period on the results of the electrical conductivity test and the mineral composition of the imbibition solution of bean seeds (Phaseolus vulgaris L.). Three seed lots of the cultivar IAPAR -81 and cultivar IPR -TIZIU were stored at 10, 25 and 25-10º C (six months at 10º C and six months at 25º C) The following evaluations were made every three months for a year: seed water content, germination and vigour (accelerated ageing and electrical conductivity) and the potassium, calcium and magnesium contents of the imbibition solution. The cultivars showed similar behavior in storage. The reduction in the vigour of bean seeds stored at 10º C was verified by accelerated ageing and electrical conductivity tests. The bean seed storage at low temperature (10º C) does not influence the results of the evaluation of seed vigour by electrical conductivity test and the quantification of calcium, magnesium and potassium ions. The evaluation of vigour by the electrical conductivity test is not recommended for bean seed stored by long periods (above 9 months). Index terms:Phaseolus vulgaris L, vigour, leaching, low temperature. RESUMOO teste de condutividade elétrica tem sido usado para avaliar o vigor de sementes de muitas espécies, especialmente de fabáceas, como ervilha, feijão e soja. Assim, nesta pesquisa, objetivou-se avaliar o efeito da temperatura e do período de armazenamento sobre os resultados do teste de condutividade elétrica e da composição mineral da solução de embebição de sementes de feijão (Phaseolus vulgaris L.). Foram utilizados três lotes do cultivar IAPAR -81 (grupo "Carioca") e três do cultivar IPR -TIZIU (grupo "Preto") armazenados a 10, 25 e 25-10º C (seis meses a 10º C e seis meses a 25º C). Ao longo de 12 meses de armazenamento, a cada três meses foram determinados: teor de água, germinação e vigor (envelhecimento acelerado e condutividade elétrica) e conteúdo de potássio, cálcio e magnésio da solução de embebição. As sementes das cultivares apresentaram comportamento semelhante no armazenamento. A redução no vigor das sementes de feijão armazenadas a 10º C foi verificada pelos resultados dos testes de envelhecimento acelerado e de condutividade elétrica. O armazenamento de semente de feijão em baixa temperatura (10º C) não influencia os resultados da avaliação do seu vigor pelo teste condutividade elétrica e a quantificação de cálcio, magnésio e potássio. A avaliação do vigor pelo teste de condutividade elétrica não é recomendada para semente de feijão armazenada por longos períodos (acima de 9 meses). Termos para indexação:Phaseolus vulgaris L, vigor, lixiviação, baixa temperatura.

Biochemical behavior of bean seeds and grains during storage

“…The present study discovered an increase of Mg 2+ during storage periods, this result is also confirmed by Fessel et al (2006), which tested corn seeds storage under higher temperatures, by Fessel et al (2010) using soy seeds under the previous conditions and by Silva et al (2012), which tested beans seeds of lower physiological quality. Alterations caused by deterioration modify the chemical composition of seeds, possibly causing magnesium increase, a less soluble ion (MARCOS FILHO, 2005).…”

“…However, variation in electrical conductivity values, over the experiment, indicates that the test wasn't sensitive enough to detect a decrease in beans vigor, corroborating with Silva et al (2012), who studied beans of high vigor; with Fessel et al (2010) who tested soy seeds stored at 10 and 20 ºC, and finally with Soares et al (2010), using sorghum seeds. However, the test was effective to distinguish beans vigor in Santos et al (2005) work, and also to batches of beans studied by Cassol et al (2012), during storage for eight and three months, respectively.…”

“…Kikuti et al (2008) and Binotti et al (2008) found a strong correlation between great release of K + and lower physiological quality of beans and peanut seeds. Different authors have been stated that potassium is the most released ion by seeds (VANZOLINI;NAKAGAWA, 2003;MARCOS FILHO, 2005;FESSEL et al, 2006;COSTA et al, 2008;FESSEL et al, 2010;SILVA et al, 2012). The results were higher than the ones observed by Binotti et al (2008), for pearl beans (0.17 mg g -1 ), and by Pereira et al (2011), for creole beans in two years of cultivation (10.92 to 20.21 mg kg -1 ).…”

“…Similar results were found by the present study, which wasn't able to use this variable (Ca) when analyzing seeds vigor. Whereas calcium increase was documented by Fessel et al (2006) for corn, by Fessel et al (2010) for soy seeds with high and low vigor, and by Silva et al (2012) in lots of beans with lower physiological quality.…”

“…High concentrations -of the above substances -can be an indicative of vigor and germination loss (MARCOS FILHO, 2005;BINOTTI et al, 2008). Among the best studied electrolytes, to try establishing a correlation with physiological quality of seeds, are calcium, magnesium and potassium, which are researched by many authors (BINOTTI et al, 2008;COSTA et al, 2008;FESSEL et al, 2010;SILVA et al, 2012).…”