Effect of Different Heavy Metals on Physiological Traits of Saffron (Crocus sativus L.)

Abstract

Increasing the concentration of different heavy metals, such as lead, copper, nickel and other heavy metals in air, soil and water can pose negative effects on the entire ecosystem and cause harmful health consequences for all forms of life. The major sources of pollution in many parts of world are overburdens of mine, industrial effluents, fertilizers and pesticides. In order to study the effects of different heavy metals on some of the physiological attributes of saffron such as photosynthetic pigments, Prolin and carbohydrates of leaf and the amount of crocin in the saffron stigmas, an experiment was conducted based on completely randomized design (CRD) with four replications and seven treatments. The experimental treatments were control and six different heavy metals (i.e. nickel nitrate, silver nitrate, zinc nitrate, copper carbonate, lead nitrate and manganese sulfate). Before sowing the corms, all of the heavy metals were added to the soil based on the concentration of 500 mg.kg-1 soil. The effects of experimental treatments on chlorophyll a, chlorophyll b, total chlorophyll and chlorophyll a/b were significant, but there was no significant effect on leaf carotenoids. Proline and soluble carbohydrates were significantly affected by the treatments. However, the effects of these treatments on reducing carbohydrates were not significant. Heavy metals also had significant effects on crocin content of the saffron stigmas. By using all of the heavy metals except for nickel nitrate, the amount of crocin increased.

Keywords

• Carbohydrates
• Environmental stress
• Proline
• secondary metabolites