Yield gains in wheat are a result of greater plant photosynthetic efficiency and better ability to tolerate biotic or abiotic stresses due to the protection of photosynthetic structures from reactive oxygen species (ROS) by efficient antioxidative system. The slower rate of senescence could be associated to higher grain yield. The objective of this study was to identify antioxidative signalling in two different winter wheat varieties which regulates the process of senescence. Concentration of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) content, activities of the antioxidant enzymes (catalase (CAT; EC 1.11.1.6), ascorbate peroxidase (APX; EC 1.11.1.11), guaiacol peroxidase (GPOD; EC 1.11.1.7) and polyphenol oxidase (PPO; EC 1.14.18.1)), chlorophyll (Chl) and carotenoid (Car) concentration as well as photosynthetic efficiency in the flag leaves were determined. Results showed that compared to high-quality variety (Olimpija), Kraljica (high-yielding variety) increased CAT, APX, GPOD and PPO activities earlier during the course time experiment, which could be the reason of delayed senescence process. Oxidative damage resulting from increased H₂O₂ accumulation with increased lipid peroxidation and a decline in antioxidative enzymes activity may contribute to accelerated senescence in Olimpija. Furthermore, delay in senescence in Kraljica was associated with a decrease in the grain protein content. As a result of declination in Chl a + b and carotenoid content, MDA concentration in the flag leaves of Olimpija gradually increased at each sampling point with decline in antioxidant enzymes activity. However, the rate of protein and chlorophyll degradation occurs normally below the green tissue where Kraljica maintained higher chlorophyll level longer then Olimpija.

小麦的增产是由于有效的抗氧化系统保护了光合结构免受活性氧（ROS）的侵害，从而提高了植物的光合作用效率，提高了其承受生物或非生物胁迫的能力。衰老速度较慢可能与谷物产量较高有关。这项研究的目的是鉴定两种不同的调节衰老过程的冬小麦抗氧化信号。丙二醛（MDA）和过氧化氢（H ₂ O ₂）含量，抗氧化酶（过氧化氢酶（CAT; EC 1.11.1.6），抗坏血酸过氧化物酶（APX; EC 1.11.1.11），愈创木酚过氧化物酶（GPOD; EC 1.11.1.7）和多酚氧化酶（PPO; EC 1.14.18.1）的活性）），测定旗叶中的叶绿素（Chl）和类胡萝卜素（Car）浓度以及光合作用效率。结果表明，与优质品种（Olimpija）相比，Kraljica（高产品种）在实验过程中较早地增加了CAT，APX，GPOD和PPO的活性，这可能是衰老过程延迟的原因。H ₂ O ₂增加导致的氧化损伤脂质过氧化作用的增加和抗氧化酶活性的下降可能会促进Olimpija的衰老。此外，克拉丽卡（Kraljica）衰老的延迟与谷物蛋白质含量的降低有关。由于Chl a  +  b的下降和类胡萝卜素的含量，Olimpija旗叶中的MDA浓度在每个采样点逐渐增加，而抗氧化酶活性下降。然而，蛋白质和叶绿素的降解速率通常发生在绿色组织以下，而卡拉利卡州保持较高的叶绿素水平的时间要长于Olimpija。