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The relationship between hydrogen peroxide and the metabolism of polyamines and the role of NADPH oxidase (NOX) in that relationship under drought conditions remains unclear. To reveal the relationship, expression levels of the genes in polyamine metabolism, such as arginine decarboxylase, agmatine aminohydrolase, spermidine synthase, S-adenosyl methionine decarboxylase, diamine oxidase, and polyamine oxidase were determined by RT PCR under drought stress combined with exogenous hydrogen peroxide (H2O2) and diphenyleneiodonium chloride (DPI) treatments in maize seedlings. In addition, some basic stress parameters (leaf water potential, lipid peroxidation), levels of polyamines (putrescine, spermidine, and spermine), and gene expression of NOX were measured under drought stress. Exogenous H2O2 induced the polyamine content by up-regulating polyamine-synthesizing genes and downregulating polyamine oxidizing genes. When the NOX enzyme was inhibited by DPI, the polyamine pathway tended towards degradation instead of production. Exogenous H2O2 regulated the metabolism of polyamines to promote their synthesis, and NOX played a key role in that regulation.

The negative effects of drought stress, which is the most effective type of stress on the yield loss of crops with a rate of 26% among abiotic stresses, are increasing day by day with global warming. The purpose of the study is to find out if Acetone O-(4 chlorophenylsulfonyl) oxime (AO) has positive effects on the metabolism of maize seedlings under drought or not. The following experimental setup was established: 18 hours distilled water Control (C), 6 hours 0.66 mM AO+12 hours distilled water (AO), 6 hours distilled water+12 hours 3% PEG (D), and 6 hours 0.66 mM AO+12 hours 3% PEG (AO+D). While ABA content decreased in AO application compared to control, it was determined that ABA decreased in AO+D application compared to D. While a difference could not be determined between AO by control and between D by AO+D applications on RWC content, it was observed that stress significantly reduced in RWC. It was determined that AO increased the Photosynthetic pigment content in the AO+D compared to the D. It was determined that AO reduced MDA and H2O2 content by regulating the activities of antioxidant system enzymes. It was observed that the proline content increased in AO application compared to control and in AO+D application compared to D. While ASA content decreased in AO application compared to control, it was determined that ASA content increased in AO+D application compared to D. Significant fluctuations in the contents of phenolic substances were determined. As a result, the pre-application of AO to maize under drought stress may prevent the formation of radicals, and this situation is thought to be due to the antioxidative properties of AO.