Effect of exogenous dithiothreitol and lipoic acid on the content of photosynthetic pigments in oilseed rape Brassica napus L.

Abstract

We studied the effect of exogenous antioxidants dithiothreitol and lipoic acid on the contents of photosynthetic pigments, including total chlorophyll and carotenoids, in the leaves of regenerated shoots of the oilseed rape cultivars Mirakel, Lagonda and Menthal (Brasisca napus L.). The shoots were obtained from hypocotyl segments cultured for six weeks on in vitro regeneration media supplemented with dithiothreitol and lipoic acid at concentrations of 1 mg.dm-3 and 10 mg.dm-3, respectively. The application of DTT and LA resulted in a significant increase in the content of total chlorophyll and carotenoids, maintaining or increasing the Chl/carotenoids ratio in the cultivars Mirakel and Menthal. Unlike the cultivar Menthal, the frequency of explant regeneration significantly decreased in the cultivar Mirakel, which may be attributed to genotype-specific responses. Mirakel exhibited a higher frequency of regeneration under control conditions compared to Lagonda and Menthal. In the leaves of the cultivar Lagonda regenerated in the presence of DTT, there was a significant reduction in chlorophyll and carotenoid contents, along with a decrease in the Chl a/Chl b ratio, suggesting a conversion of Chl b to Chl a and a biphasic effect of DTT.