Effects of Saline-alkali Stress on Nitrogen Metabolism Activity and Root Yield and Sugar Content of Suger Beet Effects of different nitrogen forms on key enzyme activity involved in nitrogen metabolism and grain protein content in speciality wheat cultivars Effects of high temperature on key enzymes activity of nitrogen metabolism in flag leaf and protein content in grain after flowering of early-indica rice Effect of Salt Stress on Ammonium Assimilation Enzymes of the Roots of Rice (Oryza sativa) Cultivars Differing in Salinity Resistance Changes of Glutamine Synthetase and Other Ammonia-Assimilating Enzymes during the Germination of the Seed and the Development of the Cotyledon in Cushaw EFFECT OF NaCl STRESS ON GLUTAMATE SYNTHASE AND GLUTAMATE DEHYDROGENASE OF RICE PLANTS Effects of Low-temperature on Enzymes Activities of Nitrogen Metabollism and Free Amino Acids Contents in Root of Malus baccata Borkh. and Malus hupehensis Rehd. Seedlings Effects of Low-temperature on Enzymes Activities of Nitrogen Metabollism and Free Amino Acids Contents in Root of Malus baccata Borkh. and Malus hupehensis Rehd. Seedlings