Effect of chronic ultraviolet b radiation on pea plants

Aim. The effect of chronic ultraviolet B (UV-B) radiation on shoots growth, content of photosynthetic pigments and hydrogen peroxide (HP) in the leaves of pea plants (Pisum sativum L.) was studied. Methods. Pea plants cultivar Gotivsky were irradiated by chronic UV-B during 5 days in the doses from 2.5 to 4 kJ/m2 per day with a power of 1 W/m2. The length of plant shoots was measured during 7 days after the end of radiation. Content of photosynthetic pigments and HP in leaves were measured on the 7 day after radiation. Results. It was shown that after the chronic UV-B radiation of pea plants with doses from 2.5 to 4 kJ/m2 per day, the length of shoots increased, most significantly after the dose of 3 kJ/m2 per day. Content of HP in mature leaves was in 2 times higher than the level of control in all variants, the content of chlorophyll and carotenoids decreased compared to the control, most significantly after a dose 4 kJ/m2 per day. Conclusions. It was shown that after the UV-B chronic radiation with doses from 2.5 to 4 kJ/m2 per day of pea plants, shoot growth increased. The content of HP in mature leaves increased, the content of photosynthetic pigments decreased. The chronic UV-B radiation caused the destruction of the pigment complex of mature pea leaves and oxidative stress, but the absence of UV-B in the light can cause the decrease of growth.