Journal of Plant Process and Function

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Abstract Cadmium (Cd) is easily absorbed by root system in many plant species and due to its solubility in water and toxicity is considered as a major pollutant. A factorial pot experiment was conducted on two cultivated and wild safflower species, in which four cultivated genotypes (Arak-2811, Saffire, C111, and AC-Sterling) and four wild genotypes (Arak, Shiraz, Isfahan and Azari) were treated by four levels of Cd (0, 1, 5, and 10 mg CdNo3/kg soil). Based on Cd Tolerance Index, chlorophyll (Chl) concentrations and lipid peroxidation Ac-Sterling, Isfahan, and Arak-2811 were ranked tolerant and Arak, C111 and Shiraz sensitive to the Cd stress. Wild and cultivated safflowers did not appear to differ in terms of the latter attributes. The greatest activities of ascorbate peroxidase (APX) and catalase (CAT) were observed to be at the 5 mgkg-1 level of Cd. The tolerant genotypes indicated a greater increase in their APX and CAT activity, compared to the sensitive genotypes. It was concluded that the enzymatic antioxidant defence system in safflower plays a major role in its response to Cd and APX and CAT antioxidants play a more crucial role in this regard, relative to GR.

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Air pollution is a serious problem at recent years which progressively increases. This study was accomplished in order to more understanding of morphological and physiological responses of acid rain on Persian maple trees as an ornamental and industrial plant. Accordingly, three-year old Persian maple seedlings were submitted based on completely randomized design to four different acid rain regimes: pH 3, 4, 5 and near neutral (pH 6) as control, in tree replications, during 10 days. At the end of experiment, some visible changes such as necrotic spots and leaf marginal wrinkle were observed in the plant leaves sprayed only with AR of pH 3. Results showed that electrolyte leakage (EL) and lipidperoxidation (LPO) amount significantly increased as pH values of AR decreased. However, reducing of AR had no effect on leaf chlorophyll content by pH 4.0, whereas AR of pH 3.0 dramatically degraded it. In addition, AR did not significantly affect superoxide dismutase (SOD) activity. On the contrary, it enhanced peroxidase (POD) and ascorbate peroxidase (APX) activities by pH 4.0, but AR of pH 3.0 markedly decreased them, thereby, the antioxidative system was weakened and injury appeared. Overall, our results cleared that Persian maple was resistant to AR by pH 4.0, while it is certainly susceptible to pH 3.0 and lower pH values.