Growth and physiological features of pea (Pisum sativum L.) of different morphotypes under ozone exposure

Abstract

Two different morphotypes of peas (Pisum sativum L.), the leafy form ‘Ilgiai’ and the subleafy form ‘Profi’, were examined under ozone exposure. A day after exposure, adverse effects of ozone on ‘Ilgiai’ morphometric features were observed, while certain processes in ‘Profi’ were stimulated. After three days of exposure, the leaf area of leafy peas was reduced by 34%, Hile in subleafy peas it increased by 33% under the 160 μg m–3 ozone level. Chlorophyll and carotenoid content in leaves of leafy peas decreased with increasing exposition time and ozone concentration. However, a linear dependence between the content of photosynthetic pigments in leaves of subleafy peas and exposition time / ozone concentration was determined, and only the highest ozone level significantly decreased the content of those pigments. The ratio of hexoses to sucrose increased in leafy peas after one day of ozone exposure, but it tendentiously decreased as the time of exposure increased. The same trends were observed also for subleafy peas, though the variation range was not so intense. However, pronounced changes in the ratio of soluble sugars were determined only after five days of exposure. Keywords: growth, ozone, peas, pigments, sugars