Abstract: With the Pressure-State-Response (PSR) model developed by the Organization for Economic Cooperation and Development (OECD) and United Nations Environment Program (UNEP), this paper assessed the ecological security of the regions along Huaihe River in Anhui Province. Based on it, a revised integrative assessment model of regional ecological security and corresponding indicator system were built, in light of the social, economic and environmental characteristics of the regions. The weight of 17 indicators was estimated by Analytic Hierarchy Process (AHP) and Delphi technique, and three mathematical functions for these indicators were established. The results showed that the integrative ecological security degree of the regions based on PSR model was 0.41, and that after adding social-economic components was 0.34. Compared with the criterion set in this paper, the two assessment results of the regions were at comparatively unsafe level. However, the difference between the two results was 20.6%. To confirm the main elements that affect regional ecological security, the assessment model and corresponding indicator system should be combined with regional characteristics, and assessed with multi-model.

Key words: Wheat, Enhanced ammonium nutrition (EAN), Net photosynthetic rate, Soluble sugar, Nitrate reductase (NR)