Response of Several Spring Barley Cultivars to UV-B Radiation and Ozone Treatment
Experiments were conducted under controlled environmental conditions to assess the impact of UV-B radiation (8 kJ m-2 d-1) and ozone (240 μg m-3) on seven spring barley (Hordeum vulgare L.) cultivars. It has been established that the impact of UV-B and ozone on various spring barley cultivars differs greatly and in most cases the cultivars which are tolerant to an impact of ozone are sensitive to UV-B and vice versa. The impact of both investigated stressors resulted in a more pronounced decrease in chlorophyll a than chlorophyll b content while the chlorophyll a/b ratio in the leaves of different spring barley cultivars has also decreased. The reaction of carotenoids differs greatly depending on a stressor. UV-B radiation causes a significant increase in the content of carotenoids which is most likely a defence reaction against high energy short-wave radiation. The impact of ozone, in contrast, resulted in a decrease in carotenoids in the leaves of different spring barley cultivars.