Abstract: Alginatederived oligosaccharide plays an aregulatory role in the growth and development of plants. The alleviation effects of spraying alginatederived oligosaccharide at different concentrations (0, 0.05%, 0.1%, 0.2%, 0.4%) on physiological characters of wheat (Qingfeng No. 1) seedlings under chlorpyrifos stress were investigated in order to discuss the influences of alginatederived oligosaccharide on plant resistance. The results showed that chlorpyrifos decreased the contents of chlorophyll a, chlorophyll b and total chlorophyll in wheat seedlings (P<0.05), but significantly increased the contents of proline, soluble protein and soluble sugars (P<0.05), thus inhibited the accumulation of total biomass and aboveground biomass, making the ratio of root to shoot increase. By contrast, spraying alginatederived oligosaccharide played a significant role in mitigation in all the above mentioned physiological and biochemical changes (P<0.05), especially at the concentration of 0.4% (P<0.01). It was concluded that alginatederived oligosaccharide improved the physiological activity of wheat seedlings to some extent, thus strengthened the plant resistance against chlorpyrifos stress.

Key words: paddy field and irrigable land, soil organic carbon density, Kriging interpolation, spatial heterogeneity, land use type