O in bread wheat Triticum

 
 
Fig. 1. Changes in the AsA amount (A), APX activity (B) in bread wheat genotypes (Gobustan and Tale 
38) at the wax ripening stage of ontogenesis. C-control, D-drought, R-rewatering. Means ± SD of three 
replicates. Results of Student's t-test: *, **, *** – significance at the 0.01, 0.05, and 0.1 probability levels, 
respectively, ns – not significant. FM – fresh mass. 
Fig. 2. Changes in the GR activity (A) and GSH amounts (B) in bread wheat genotypes (Gobustan and Tale 
38) at the wax ripening stage of ontogenesis. C-control, D-drought, R-rewatering. Means ± SD of three 
replicates. Results of Student's t-test: *, **, *** – significance at the 0.01, 0.05, and 0.1 probability levels, 
respectively, ns – not significant. FM – fresh mass.

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Ascorbate-glutathione cycle for scavenging H
2
O
2
 in bread wheat (Triticum aestivum L.) genotypes 
65 
Glutathione, enzymatic, and non-enzymatic 
antioxidant systems reduce osmotic stress in maize 
and wheat caused by drought. Thus, the effect of 
osmotic stress caused an accumulation of GSH in 
maize and an increase in the GR activity in wheat 
(Hasanuzzaman et al., 2017). We observed the 
increased GR activity in the drought-exposed 
variants of the Gobustan variety, which was 
partially recovered after rehydration. However, in 
the Tale 38 variety, the GR activity decreased 
compared with the control in the drought-exposed 
variants and recovered after rehydration. The 
activity of GR was found to increase in both 
varieties under drought and recovered after 
rehydration. In the Gobustan variety the enzyme 
activity decrease was relatively small (Fig. 2A). 
As H
2
O
2
is a substrate for many enzymes, an 
increase in its amount results in the enhancement of 
the activities of the respective enzymes. Besides, 
H
2
O
2
is used as a source of oxygen in light 
reactions of photosynthesis and may have a 
stimulating effect on plant growth (Huseynova et 
al., 2015). Hydrogen peroxide amounts on a fresh 
weight basis were greater in all variants of the 
Gobustan variety compared with the Tale 38 
variety. But in these varieties, the tendency of the 
change was the same.