Abstract: The study shows that soaking maize seeds with 100 and 1000 mg· L^-1 of extract B from Cyperus rotundus ca promote their seedling growth and uptake of N, P and K, but 10000 mg· L^-1 of the extract will inhibit P absorption. Soaking rice seeds with 1000 mg·L^-1 of it can inCrease the vitality of the root system of their seedlings, the uptake of P and K,the number of productive tiller and the yield of grain. At ear forming stage of rice, the activities of nitrate reductase and peroxidase in terminal leaves are increased, but that of fumaric reductase in root system is decreased.

Key words: Cyperus rotundus, Extract B, Soaking seed, Enzyme activity, Bioeffect, ecological quality index, Beijing-Tianjin-Hebei (BTH) urban megaregion, remote sensing, ecological quality assessment