Abstract: Influences of CO2/salt shock on the growth status, chlorophyll contents and activities of enzymes including tricarboxylic acid cycle (isocitric dehydrogenase (IDH), malic dehydrogenase (MDH), succinic dehydrogenase (SDH)) and photorespiratory pathway (glycolate oxidase (GO), hydroxypyruvate reductase (HRR), catalase) in seedling of wheat with different salt tolerance have been studied. Results showed that the growth of two wheat varieties were inhibited by NaC1 and stimulated by CO2, the responses being greater in the salt-stressed than in the non-salt-stressed plants. The chlorophyll contents at two wheat varieties were decreased by NaC1 while chorophyll levels were elevated by CO2. The activities of SDH, IDH, MDH in TCAC, and GO, HPR in photorespiratory pathway were stimulated by NaCI in salt-sensitive wheat, whereas these enzymes activities were inhibited by CO2, their response being different in salt-tolerant wheat. Data suggested that increased CO2 levels might alleviate the adverse effects of salinity.

Key words: alt stress, CO2 double increase, Respiratory enzyme, Photorespiratory enzyme, Wheat