Radish plant behaviour under short-term elevated ozone fumigation

Abstract

Effects of short-term ozone (O3) fumigation on radish (Raphanus sativus L.) plants were examined in growth chambers under controlled environment conditions. Plants were exposed to 0 μg/m3 (reference), 80 μg/m3, 160 μg/m3 and 240 μg/m3 O3 concentrations for 7 h per day for five days. Day/night temperature was 21°C/14°C and photoperiod 16 h. Chlorophyll content was evaluated spectrophotometrically. Chromatographic analysis of saccharides was also undertaken. The results showed that elevated O3 inhibited the growth of radish rhizocarps, net assimilation rate and biomass accumulation. O3 induced leaf desiccation, necrosis and premature senescence, but a typical reaction of plants to O3 stress was the rapid regeneration of new leaves. O3 inhibited accumulation of carotenoids more than chlorophylls. The higher photosynthetic pigment content in newly generated radish leaves may be regarded as an adaptation of the photosynthetic system to O3. Leaf saccharide metabolism and incorporation depended on O3 concentration. Rapid regeneration of new leaves and increased content of photosynthetic pigments is the typical reaction of radish plants to O3 stress. © 2010 Versita Warsaw and Springer-Verlag Wien.