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 g 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. Kontroliuojamomis aplinkos s lygomis tirtas ultravioletin s (UV-B) spinduliuot s (8 kJ m–2 d–1) ir ozono (240 μg m–3) poveikis septynioms vasarini 3 mie i 3 (Hordeum vulgare L.) veisl ms. Tirt 3 mie i 3 veisli 3 jautrumas ultravioletin s spinduliuot s poveikiui labai skyr si nuo j 3 jautrumo ozono poveikiui. Daugeliu atvej 3 veisl s, pakan ios UV-B spinduliuotei, buvo jautrios ozono poveikiui ir atvirk iai. Nustatyta, kad abu tirti stresoriai slopino chlorofilo sintez , chlorofilo a koncentracija suma jo labiau nei chlorofilo b. Taip pat suma jo chlorofilo a ir chlorofilo b santykis. D l UV-B spinduliuot s karotinoid 3 koncentracija lapuose padid jo, d l ozono poveikio, prie ingai, karotinoid 3 koncentracija vis 3 tirt 3 veisli 3 mie i 3 lapuose suma jo.