Changes in photosynthetic dispositions in pea plants caused by fluoranthene and flurochloridone: from the subcellular level to the anatomical changes

Environment is polluted with the wide spectrum of foreign substances of the anthropogenic origin. Because plants are not able to move from place to place and they are able to take up these pollutants through roots and leaves, it can adversely affect their metabolism and growth. The present study refers about the effect of polycyclic aromatic hydrocarbon fluoranthene (FLT) and herbicide flurochloridone (FLC) on photosynthetic disposition of pea plants (Pisum sativum L.), using the traditional anatomical studies and modern non-invasive methods such as measurement of chlorophyll fluorescence. The presented results shown that 5 µM FLT and/or FLC negatively influenced photosynthetic system at all levels from the subcellular level, through the leaf anatomical structure, to the growth habit of the plants. Damages caused by both compounds were significantly observed as the decrease of chlorophyll fluorescence parameters which were in correlation with decrease in levels of photosynthetic pigments, mainly chlorophyll b and carotenoids. Significant changes were detected in the leaf anatomical structure, where influence of both substances led to the modification of the bifacial mesophyll. About the damage of chloroplasts and their membranes refer the higher levels of malondialdehyde and the smaller size of these plastids caused by FLT. The colorless plastids were observed in leaf cells of FLC-treated plants. Above-mentioned effects led to the growth inhibition and decrease in biomass production ability of the affected plants.