Effects of day-night supplemental UV-A on growth, photosynthetic pigments and antioxidant system of pea seedlings in glasshouse

Abstract

A glasshouse experiment was carried out to investigate the effects of day-night supplemental UV-A on growth, photosynthetic pigments and antioxidant system (contents of antioxidant substances and antioxidant enzyme activity) of pea seedlings substrate-cultivated in glasshouse. The results show that supplemental UV-A did not significantly affect shoot and root to shoot ratio of pea seedlings, but root and total biomass were modified.  Day supplemental UV-A slightly increased root and total biomass of pea seedlings, while night supplemental UV-A significantly decreased the root and total biomass. Supplemental UV-A did not affect the contents of  shoot chlorophyll a and carotenoid of pea seedlings. Nevertheless, day supplemental UV-A significantly  decreased chlorophyll b content in shoot of pea seedlings, while night supplemental UV-A slightly decreased  shoot chlorophyll b content. In addition, supplemental UV-A did not significantly affect the contents of shoot  vitamin C, phenolic compounds and flavonoid of pea seedlings. However, day supplemental 6 h and night  supplemental 3 h slightly decreased shoot anthocyanin content of pea seedlings, while night supplemental 6 h significantly reduced shoot anthocyanin content. Finally, supplemental UV-A did not significantly affect shoot peroxidase activity and catalase activity.

Key words: UV-A, photosynthetic pigment, antioxidant enzymatic activity, antioxidant substance, pea seedling