Respostas ecofisiológicas, enzimáticas e de produtividade de plantas de trigo provenientes de sementes com diferentes níveis de vigor e expostas a restrição hídrica Felipe Koch Pelotas,

Abstract

The present work aims to evaluate enzymatic and chemical composition responses of seedlings and ecophysiological and plant productivity responses of different wheat cultivars from seeds with different levels of vigor and exposed to water restriction. Seeds of different cultivars were used, with high, medium and low vigor, and the water restriction was performed at different stages of crop development. In the field, experiments were carried out to study the relationship between cultivars x vigor of seeds, already in greenhouse, the experiments were to analyze the relationship between cultivars x level of seed vigor x water restriction. The use of low vigor seeds negatively affects the establishment of the wheat plant stand. The use of high vigor seeds provides a greater number of wheat and ear plants per area. The productivity was significantly affected by seed vigor levels, with up to 11% increase for high vigor batch compared to low vigor. Plants of high vigor seeds stand out in growth, with a superiority of up to 27% for leaf area index values, 28% for total dry matter, 30% for dry mass production rate, 19% for relative growth and up to 44% for the conversion efficiency of solar energy. The mass of one thousand seeds is superior for plants coming from seeds of high vigor. High vigor seeds provide a higher speed and seedling emergence percentage. The growth response of the wheat is independent of the cultivar employed, having superiority to plants originated from seeds with high vigor in field capacity. Plants exposed to water restriction have a higher activity of antioxidant enzymes, independent of the cultivar. The high vigor level of the seeds promotes an increase in the values of the enzymatic activity of the plants when exposed to the water restriction. The high vigor of the seeds results in the formation of plants with larger leaf area and superior allocation of dry mass in aerial part and in the roots, both in conditions of field capacity and in conditions of water restriction. The total dry matter production, dry mass production rate, net assimilation rate, leaf area index, leaf mass ratio and conversion efficiency of solar energy were higher for plants from high vigor seeds and kept under field. Yield is higher for plants originating from high vigor seeds than those with low vigor in soil maintained at field capacity.