Akbar Shabani, Mohsen Saeidi, Ali Ahmadi, Foad Moradi:
Some Physiological and Biochemical Treatments in Relation to Sink and Source Strength in a Water Stress Resistant and a Sensitive Cultivars of Wheat under Post Anthesis Water Stress


1Dry Land Agricultural Institute of Iran, Iran
2Razi University, Crop Production and Plant Breeding, Iran
3Tehran University, Crop Production and Plant Breeding, Iran
4Agricultural Biotechnology Research Institute of Iran, Physiology and Proteomics, Iran

The grain development and filling stage is one of the main steps in the formation of the final economic yield of wheat. In Mediterranean regions (such as Iran) occurrence of water stress during the grain filling period is the main factor for a significant yield reduction. This research was performed in order to evaluation the effects of post anthesis water stress on some physiological characteristics in relation to sink and source strength of two wheat cultivars: Zagros cultivar (ZC) and Marvdasht cultivar (MC) that are resistant and sensitive to post anthesis water stress, respectively. This study was performed in the research greenhouse of the agricultural faculty of Tehran University, Iran in 2005 and 2006. A factorial experiment on base of a randomized completed block design with three replications was used.

Under no-stress conditions the grain yield, biomass yield, 1000 grains weight and no of grains in spike of MC was higher than ZC. Under stress situations all characteristics, but for the no of grains in spike, decreased more for the MC than for the ZC. Under control treatment, chlorophyll a and b and soluble protein concentration, photosynthesis rate and stomatal conductance of ZC flag leaves were greater than MC.

After post anthesis, the maximum concentration of IAA was found at the early grain growth stage (cell division and cell growth) and the maximum ABA concentration at the beginning of grain filling (17 days after anthesis). Water stress significantly decreased IAA and increased ABA concentration in the grains of both cultivars. In the control and the water stress treatments ABA concentration in the grains of MC was higher than ZC.

With respect to the results of this research, IAA may be involved in the regulation of cell division and cell growth and hence in the formation of sink size. A reduction in IAA and an increase in ABA concentration at the beginning of grain filling stage may be the most important factor that is involved in switching from cell division and enlargement phase to grain filling phase.

Keywords: Abscisic acid, Indole acetic acid, photosynthesis, soluble protein, stomatal conductance, water stress, wheat

Full paper: http://www.tropentag.de/2010/abstracts/full/149.pdf


Contact Address: Akbar Shabani, Dry Land Agricultural Institute of IranVila Street, 6714647169 Kermanshah, Iran, e-mail: ashabani51@yahoo.com
Andreas Deininger, October 2010