Effects of Cadmium Stress on Physiological Characteristics, Pod Yield, and Kernel Quality in Peanut

The objectives of this study were to study the effect of cadmium (Cd) stress on peanut (Arachis hypogaea L.) growth and kernel yield and quality, and provide a guide for the safe production of peanut. In the pot experiments carried out in 2009 and 2010, 2 cultivars, Yuhua 15 and XB023, were cultured under light (1.0 mg kg⁻¹), medium (2.5 mg kg⁻¹), heavy (7.5 mg kg⁻¹), and high (15.0 mg kg⁻¹) Cd stress. No Cd stresses treatment was used as the control. The vegetative growth of peanut plants were stimulated under light and medium Cd conditions, but depressed under heavy and high Cd conditions. The chlorophyll contents and photosynthetic rates of leaves of Yuhua 15 decreased with the increase of Cd concentrations. The chlorophyll contents of XB023 were increased under light and medium Cd stresses and decreased under heavy and high Cd stresses, while photosynthetic rates of leaves of XB023 decreased with the increase of Cd concentrations. The sensitivities of yield to Cd stress were different in the 2 cultivars. Yuhua 15 were more sensitive to Cd stress than XB023, because yield per pot, kernel weight per pot, kernel rate per pod, and pod number per plant in Yuhua 15 were significantly reduced under medium or higher Cd concentrations, while those in XB023 were significantly reduced under heavy and high Cd concentrations. The influence of Cd stress on seed quality also had genotypic interaction. In Yuhua 15, Cd stress increased the content of soluble sugar and decreased the contents of protein and oil, as well as the ratio of oleic-acid-to-linoleic-acid (O/L); in XB023, Cd stress decreased the contents of soluble sugar and oil and O/L ratio, and light and medium Cd stresses increased the contents of protein and its components of Lys and Thr in peanut kernels. In both cultivars, the Cd contents in kernel were higher than that in the control. Yuhua 15 had higher Cd content in plant and lower Cd content in kernel than XB 023.