Abstract: To have a deep understanding on the mechanisms of cadmium (Cd) toxicit y on peanut plants is of theoretical and practical significances for the selecti on and utilization of Cd-resistant peanut germ plasm resources. With fourteen peanut varieties as test materials and taking the chlorophyll content of functio nal leaves, malondialdehyde (MDA) content and cell membrane permeability of root s and leaves, and oxidative vitality of roots at flowering stage as test physiol ogical parameters, a sand culture experiment was conducted in an artificial clim a te chamber to investigate the physiological responses of different peanut variet ies to six levels of Cd stress. The results showed that within the range of 0〖 KG-*2〗-〖KG-*7〗60 mg Cd·L-1 addition, the chlorophyll content of functional leaves and the oxida tive vitality of roots decreased significantly with increasing Cd addition, whil e the MDA content and cell membrane permeability of leaves and roots were in adv erse. The cell membrane permeability of roots and leaves was the most sensitive physiological parameter, while the chlorophyll content of functional leaves was the least sensitive one in the responses of peanut plant to Cd stress. In the li near regression equations describing the relationships between test physiologica l parameters and Cd concentrations in nutrient solution, the absolute value of s lope (b)/intercept (a) ratio, ︱b/a︱, could better describe the sen sitivity of peanut plants to Cd stress. It was known from the integrative evaluation of︱b/a︱values and the cluster analysis of sensitivity that among the fourteen peanut varieties, “Zhonghua-4”, “Xiangnong-55” and “Xiangnong-3010-w” were hi ghly sensitive to Cd stress (first grade), “Lainong-29”, “Xiangnongxiaoguo-w2-7”, “Fenghua-2”, “Lainong-13”, “Yuhua-15” and “Fenghua-3” were sensitive (second grade), “Xiangnong-312”, “Qiyangxiaozi” and “Pingdu-01” were less sensitive (third g rade), while “Huayu-20” and “Huayu-23” were insensitive (forth grade).

Key words: Yellow River Delta, spatial variability, soil salinity, multi-scale