Effect of N and drought stress on seed carbohydrate and nitrogen reserves and seedling vigor in barley(Hordeum vulgare L.)

Seed reserves are controlled by genetic and environmental condition such as nutrition, temperature, drought stress and light intensity. Strong seedling will produce from seeds with high reserves. Therefore, in this work that conducted in pot, field(in Tabriz university) and lab(in Shahrood university of technology) experiments, effect of pre-anthesis nitrogen application and a drought stress during grain filling stage on seed carbohydrate and nitrogen reserves and seedling vigor from these seeds were investigated. Two barley (Hordeum vulgare L.) cultivars named Walfajr and Reihan affected by nitrogen and drought stress levels in a randomized complete block design as factorial split plot with three replications. Three levels of nitrogen (60, 120 and 180 kgha-1) and three irrigation levels (80-85, 55-65 and 35-45 percentage of field capacity) were applied at heading and 10 days after anthesis, respectively. Soil water was controlled by pot weighing and determination of soil moisture in pot and field experiments, respectively. Seed reserves including soluble sugar, starch and nitrogen and seedling vigor from these seeds with different reserves were evaluated. The high N application improved seed reserves. The mild drought stress treatment compared with the well water treatment increased the grain non structural carbohydrate and nitrogen and seed weight, but, these traits decreased by sever drought stress treatments. The grain protein enhanced by 1.3-3.3 % at drought stress treatments. The seeds that harvested from NN MD treatment had proper reserves, and germination rate, coleoptile length, root length and shoot weight in these seeds were higher than from other treatments. EC was low in seeds that obtained from NN and HN significantly. Seed germination rate was higher in Reihan, but, seed reserves in Walfajr were higher and seedling in Walfajr was stronger.