اثر كاهش قدرت منبع بر انتقال مجدد كربوهيدراتهاي محلول ساقه در سه رقم جو

Effects of source strength reduction on retranslocation of stem water-soluble carbohydrates in three barley cultivars

In a field experiment, effects of source strength reduction including removal of flag leaf, removal of leaves below flag leaf and removal of awns at anthesis in three six-rowed barley cultivars (Hordeum vulgare L.) named Star, Reihan and Walfajr were studied using a randomized complete block design as split split plot with three replications. Results showed that flag leaf removal did not affect dry weight and water soluble carbohydrates (WSC) content of stem top or low part; however, removal of leaves below flag leaf both in stem maximum weight and at maturity significantly reduced WSC content of stem parts. On the other hand, while awns removal was a kind of source strength reduction, WSC content of stem parts significantly increased at maturity. Probably reduction of cytokinins transport from roots to ears and decreased number of endospermic cells in grains results in reduction of sink demand for assimilates. Based on differences of WSC content between stem maximum weight and maturity, in each cultivar top part of stem contributed WSC to grain filling more than low part. Generally, retransloction of stem WSC to grains of main ear in Star, Reihan and Walfajr were 1.83, 6.39 and 0 percent of final grain weight of barley main ear,respecyively.