Drought stress at grain filling is the prominent and inevitable characteristic of arid and semi-arid areas. The objectives of this research were to determine the effect of drought stress and the role of current of assimilates on grain filling, storage capacity and contribution of stem reserves to the growing grains. Therefore, an experiment was carried out in a split-plot factorial arranged in a randomized complete blocks design with three replications during 2010-2011 season cropping cycle in research farm of Razi University in Iran. The moisture regimes were well watered (non-water stress) and drought stressed (post-anthesis water deficiency with withholding of irrigation and continued until physiological maturity). The barley cultivars (Hordeum vulgare L.) including Aras, Afzal, Jonub, Reihan, Zarjo, Sararud, Sahra, Fajr-30, Karoun, Gorgan-4, Makuei and Nosrat, also the source manipulation treatments including control, defoliation of flag leaf, defoliation of all leaves except the flag leaf, de-awning and ear shaded were imposed at anthesis. The results showed that, grain yield (GY) was reduced by 20.7% under drought due to 9.8 and 15.3% reduction in thousand grain weight (TGW) and number of grains per spike (NGS), respectively. Under removing of assimilate sources, remobilization of stored material from the stem internodes was increased and these results suggest the compensatory role of different part of stem in preventing yield loss. Drought stress could not increase the remobilization efficiency (RE), but in terms of mentioned traits, there were significant differences between cultivars and different removing photosynthetic sources. Cultivars with longer internodes had greater amounts of photo-assimilates in different parts of the stem and also higher amount of remobilization to the growing grains than in comparison to cultivars with shorter internodes. In both well water and drought stress treatments, the amounts of remobilization from different parts of stem to the growing grains were similar, but under well watered condition due to higher photosynthesis rate compare to drought stress condition, GY was higher
کلید واژگان :barley; drought stress; grain growth; internode; remobilization
ارزش ریالی : 500000 ریال
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