Responses of wheat grain weight and remobilization of solube carbohydrates to source limitation

While lacking water threaten the Production of agricultural products, any growth behavior is irrelevant, wasting water and inefficient. The aim of this study was to determine the optimal Wheat leaf area to achieve the balance in wheat leaves under water stress conditions was the source and sink.This experiment was a split plot based on RCBD with three replications on the Pishtaz variety of wheat were done in educational-research farm of Tehran University (Karj) during 2014-2015. The main plot with two humidity levels of normal and moderate stress and the secondary plot with four separate level of defoliation were designed. Analysis of data showed that there was no significant interaction between different level of defoliation and humidity stresses beside it has been reviled that humidity stresses hadn’t had a significant effect on yield of spike. In contrast defoliation had significant effect on yield of spike and seed weight in different parts; in this respect, there was a significant difference between defoliation levels. Among different part of spike the mid part had the less reduction of seed weight. The number of seed in different parts of spike hadn’t had any significant changes after defoliation and Water treatments. Between applied defoliation and humidity stress treatments in term of releasing soluble stored carbohydrates was a significant interaction leading to significant increase in remobilization of stem soluble carbohydrates toward seed.