Organo-specific accumulation of phenolic compounds in a buckwheat seedlings under aluminium-acid stress

Abstract

Toxic effect of aluminum contamination is one of the causes of valuable crops yield loss all over the world. It is considered that plants’ phenolic compounds play a key role in aluminium detoxification by chelation of aluminium ions in the aboveground part of aluminium-accumulating plants. However, recent evidence shows the chelating ligands involvement in both the internal and external aluminium detoxification in plants. The aim of the study was to determine the total phenolic compounds, flavonoids, anthocyanins accumulation and the activity of phenylalanine ammonia-lyase (PAL) as the key enzyme in phenolic compounds synthesis in seedlings of common (Fagopyrum esculentum Moench.) and tartary (Fagopyrum tataricum (L.) Gaertn.) buckwheat in response to the chronic aluminium-acid stress. It was recorded that addition of 50 μM Al2(SO4)3·18H2O to the nutrient medium led to the accumulation of phenolic compounds in all organs of both studied species on the tenth day of the plant exposure to stress. Species-specific and organ-specific accumulation of certain classes of phenylpropanoids was recorded. On the tenth day of stress, PAL activity was increased in the leaf tissues of both buckwheat species, but was decreased in common buckwheat root tissues and no statistically significant changes were observed in tartary buckwheat root tissues. Species and organ specificity of phenylpropanoids accumulation in the studied species is considered to be an adaptive reaction under conditions of aluminum stress.

Keywords

• aluminium phytotoxicity
• phenolic compounds
• phenylalanine ammonia-lyase
• fagopyrum esculentum
• fagopyrum tataricum