Treatment with polyamines alleviates the effects of concomitantlyapplied aluminum in sunflower (Helianthus annuus L.) leaves

Abstract

Contamination of agricultural soils with heavy metal is a significant risk for the environment. Many substances are reported to alleviate the toxic effects of heavy metals such as polyamines. The aim of this study is to examine whether the toxic effects of 0.1 mM aluminum, which is previously detected in sunflower leaves, might be alleviated with 0.1 mM putrescine, spermine or spermidine and to compare the effects of putrescine, spermine and spermidine in the ameliorating process. Chlorophyll a, carotenoid and anthocyanin content increased after putrescine, spermine and spermidine treatment under aluminum toxicity. However, chlorophyll b and total chlorophyll content only increased after spermine treatment. Intense accumulation of reactive oxygen species under aluminum toxicity decreased after putrescine, spermine and spermidine treatment while the spermine showed the maximum decrease. Superoxide dismutase enzyme activity and hydrogen peroxide content increased after putrescine, spermine and spermidine treatment while the spermine showed the maximum increase. Besides, catalase enzyme activity increased only after spermine treatment. Results showed that 0.1 mM putrescine, spermine and spermidine increased the 0.1 mM aluminum toxicity tolerance of sunflower leaves by modulating the reactive oxygen species detoxification metabolism. Spermine was the most effective polyamine in improving the aluminum tolerance.