Evaluation of lignin content of soybean seed coat stored in a controlled environment

Abstract

-Breeding soybean for high seed quality is an important approach for developing cultivars for tropical regions, and the lignin content in the seed coat is one of the screening parameters for this trait. Considering that many breeding lines are evaluated in each growing season using the presently recommended method for lignin determination, a long period is required for the evaluation of the whole breeding program. This time limitation may influence lignin content assessment, if lignin is degraded during storage. This research reported was designed to determine whether lignin was degraded in the seed coat of soybean seed cultivars stored for one year in a controlled environment (10°C temperature and 50% air relative humidity). Seeds of 12 selected soybean cultivars that had a range in seed coat lignin content were evaluated. Seeds were hand harvested just after physiological maturity and evaluated for seed coat lignin content at harvest and after one year of storage in a cold room (10°C and 50% RH). The lignin content in seed coats differed significantly among cultivars in both analyses, but for both results the sequence of cultivar classification and the lignin content values of each cultivar did not change. A regression analysis of lignin content at harvest and after one year of storage indicated a direct relationship between both lignin determinations suggesting no differences between the lignin content of each cultivar due to prolonged storage (r 2 = 0.98***).This indicates that the lignin determination in the soybean seed coat can be performed over a long time period without any bias due to change in its content.Index terms: Glycine max, plant breeding, seed quality, seed storage AVALIAÇÃO DO CONTEÚDO DE LIGNINA DO TEGUMENTO DE SEMENTE DE SOJAARMAZENADA EM AMBIENTE CONTROLADO RESUMO -O melhoramento de soja para alta qualidade de semente é um importante enfoque para o desenvolvimento de cultivares para as regiões tropicais, e o conteúdo de lignina no tegumento da semente é um parâmetro para seleção, visando essa característica. Considerando que muitas linhagens são avaliadas em cada safra, utilizando a metodologia recomendada para a determinação de lignina, um longo período de avaliação é requerido para atender todo o programa de melhoramento. Se a lignina se degradar durante esse período de armazenamento, o tempo total de avaliação do programa pode ser uma limitação a influenciar nos resultados. O presente estudo foi planejado para avaliar se a lignina sofre degradação durante um ano de armazenamento em ambiente controlado (10 ºC de temperatura e 50% de umidade relativa do ar). Sementes de 12 cultivares selecionadas com distintos conteúdos de lignina no tegumento foram avaliadas. As sementes foram colhidas logo após o ponto de maturidade fisiológica ter sido atingido (R7) e avaliadas para o conteúdo de lignina na época de 221

Influence of lignin content in soybean seed coat on the incidence of the storage fungus Aspergillus flavus

“…The differences observed for lignin content on seed coat among the cultivars assessed in the present study were statistically significant (Table 2); as found by Gris et al (2010) in studies performed with conventional and transgenic (RR) soybean seeds. However, it has not been found statistically significant changes for this parameter after a 180 days storage period (Table 2), as observed by Krzyzanowski et al (2008) after a storage period of 12 months. Results on lignin content present in the seed coat and in the ranking of cultivars are in agreement with those results previously observed by Alvarez et al (1997).…”

Methodology for the selection of soybean strains for germination, vigour and field emergence

“…Alguns trabalhos foram realizados visando selecionar caracteres para a melhoria da qualidade de sementes de soja, buscando: resistência a dano mecânico, alto desempenho germinativo em ambientes tropicais de alta temperatura e umidade relativa, resistência a doenças, tamanho da semente, permeabilidade da parede da vagem e propriedades do tegumento (CARBONELL; KRZYZANOWSKI, 1995;DELLAGOSTIN et al, 2011;GASPAR-OLIVEIRA, 2014;KRZYZANOWSKI, 1998;KRZYZANOWSKI et al, 2008).…”

Soybean Seed Phenolics, Sugars, and Minerals Are Altered by Charcoal Rot Infection in MG III Soybean Cultivars

“…Our results support the previous research in that lignin could be related with mechanical support, water transport, and defense against pathogens [33] [34], and lignin deposition in the seed coat tissue provides mechanical resistance and cell wall protection against microorganisms. When six soybean cultivars were investigated, it was found that the cultivars Doko and Parana had higher content of lignin and peroxidase activities compared with cultivars Savana, Paranagoiana, FT-10, and Santa Rosa, indicating that phenolics, including phenol, lignin, and isoflavones, are associated with defense against charcoal rot [35] [36]. The higher concentrations of total isoflavones in MR cultivar than in S cultivar in NINF and INF under irrigated and non-irrigated indicated also possible association between charcoal rot resistance and isoflavones levels.…”

“…Lignin constitutes a major component of cell wall, giving rigidity, structural support and impermeability to water [33] and is important for mechanical support, water transport and resistance against pathogens in vascular plants [33] [34]. Previous research showed that lignin deposition is related with mechanical resistance, cell wall protection and microorganism resistance [35], and mechanical damage was related to lignin content and peroxidases activity [36].…”