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The effect of terminal water stress on physiological cahracteristics and sink- source relations in two bread wheat (Triticum aestivum L.) cultivars
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Abstract: (4344 Views) |
| In arid and semi arid areas as Iran water stress at different grain growth stages is one of the major concerns for wheat production. This research was conducted to evaluate the effects of two levels of water stress (at cell division and grain filling stages) on some physiological and biochemical characteristicss related to the sink-source relationship of two bread wheat cultivars (Marvdasht and Zagrose sensitive and resistant to post-anthesis water stress, respectively). A factorial experiment based on randomized complete block design with three replications was used in greenhouse conditions. The treatments were two levels of water stress including (1) water stress (50% of FC) during fist 14 days following anthesis and re-watering (stage 1) and (2) water stress from 14 days after anthesis to physiological maturity (stage 2) and (3) control (the water status maintained at FC). In control treatment grain yield, biomass, 1000 grains weight and number of grains.spike-1 in Marvdasht was significantly greater than Zagrose. Water stress levels significantly reduced all traits in both cultivars, with greater effect on Marvdasht. Effect of wtare stress in stage 2 was more severe than in stage 1. Water stress significantly reduced photosynthesis rate, stomatal conductance, chlorophyll a and b and soluble protein content in flag leaves of both cultivars. However, concentrations were higher in the flag leaf of Zagrose. The highest concentrations of IAA and ABA were observed in stage 1 and early stage 2, respectively. Water stress in grain filling stage significantly increased ABA in the grains of either cultivars. Based on these results, water stress during stage 2 had more effect on grain yield. Water stress during cell division (stage 1) with increased ABA and reduction IAA content might reduced cell division, while during grain filling (stage 2) increasing ABA content reduced enzyme activity and duration of grain filling, hence grain yield decreased. . |
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| Keywords: Abscisic Acid (ABA), Cell division, Grain filling, Indole Acetic Acid (IAA), Photosynthesis, Water stress and Wheat |
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Full-Text [PDF 513 kb]
(1914 Downloads)
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Type of Study: Scientific & Research |
Subject:
Special
Received: 2015/02/22 | Accepted: 2015/02/22 | Published: 2015/02/22
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