Effects of Cadmium Stresses on Physiological Characteristics, Pod Yield and Seed Quality of Peanut

A pot experiment was carried out to study the effects of different cadmium concentrations on peanut physiological characteristics, yield and quality using peanut cultivars of Yuhua 15 and XB 023. Five Cd concentrations [0.0 mg kg^-1 (CK), 1.0 mg kg^-1 (light Cd stress), 2.50 mg kg^-1 (medium Cd stress), 7.50 mg kg^-1 (heavy Cd stress) and 15.00 mg kg^-1 (high Cd stress)] were treated by basal dressing in 2009 and 2010. The results showed that light and medium Cd stresses could promote peanut vegetative growth, but heavy and high Cd stresses inhibit its growth. Heavy and high Cd stresses decreased the chlorophyll content and photosynthetic rate of the two peanut cultivars while light and medium Cd stresses increased the chlorophyll content of XB023 leaves. Cd stresses decreased the yield of pod and kernel. The yield of Yuhua 15 decreased obviously when the Cd concentration reached 2.50 mg kg^-1 (medium Cd stresses), however, for XB023, reached 7.50 mg kg^-1 (heavy Cd stresses). Cadmium stress had different influence on peanut quality in different cultivars. It could increase the content of soluble sugar, decrease the content of protein and oil, and reduce the ratio of oleic acid to linoleic acid (O/L) in Yuhua 15 kernels, But decrease the content of soluble sugar and oil, reduce the ratio of oleic acid to linoleic acid(O/L) in XB 023 kernels. Light and medium Cd stresses could increase the content of protein and its components of Lys and Thr in peanut kernels. Cd stresses could increase the cadmium content in peanut. The cadmium content was higher in Yuhua 15 plants than in XB 023 plants, but was less in seed kernel than in XB 023 kernel.