Tesis
Lignina no tegumento de semente de soja: deterioração por umidade e dano mecânico e tamanho de amostra para o teste de tetrazólio
Fecha
2015-02-20Registro en:
HUTH, Caroline. Lignin on soybean seed coat: deterioration in humidity and mechanical damage and sample size for tetrazolium test. 2015. 96 f. Dissertação (Mestrado em Agronomia) - Universidade Federal de Santa Maria, Santa Maria, 2015.
Autor
Huth, Caroline
Institución
Resumen
Soybeans are the main oilseed grown in the world, and among the factors that hinder the
production of high-quality soybeans, is the frequent rainfall during periods of maturation and
preharvest. Characteristics of seeds as the seed coat lignin content may reflect a greater or
lesser susceptibility to deterioration from humidity and mechanical damage. Thus, although
there are data and evidence that the lignin content confers resistance to deterioration from
humidity, there is a lack of experiments with methods which are similar to the adverse
weather conditions that the seeds remain exposed in the field. Therefore, this study was
developed in order to evaluate the relationship between the lignin content of soybean seed
coat, with tolerance to deterioration from humidity and mechanical damage. The work
primarily consists of a brief literature review, Chapter I, and two more chapters. Chapter II
contains the work that evaluates the relationship between seed coat lignin content of soybean
seeds with tolerance to deterioration from humidity and mechanical damage. Chapter III, to
qualify the experiments in the area, is aimed to estimate the ideal sample size, in number of
seeds required for the tetrazolium test for soybean seeds. The CD 208 and CD 215 cultivars,
with higher lignin content in seed coat, 4.19% and 2.64%, respectively, had higher vigor after
stress with simulated rainfall. Furthermore, the cultivar CD 208, was also less susceptible to
damage from humidity and mechanical damage. Oxidative stress in shoots and roots of the
seedlings was demonstrated by the enzyme peroxidase activity Guaiacol, which increased the
cultivars CD 215, CD 202 and BRS 184, with lower lignin content in seed coat than 3%.
About the seeds, the cultivar BRS 184 with lower lignin content, 1.69%, showed a higher
oxidative stress due to increased activity of the enzyme Guaiacol Peroxidase and lipid
peroxidation. The sample size in number of seeds, to assess humidity damage through the
tetrazolium test in soybean seeds is dependent on the physiological quality of cultivars,
recommending to the highest level of precision 200 seeds per lot, and for a below level and
acceptable accuracy, 0.5% CI, 121 seeds.