Abstract: With winter wheat variety Yamgmai 12 as test object, a field experiment was conducted to study the stress of simulated acid rain on its growth and development. The results showed that simulated acid rain had considerable effect on wheat growth and yield. When the pH of acid rain was ≤3.5, the growth of leaf area as well as the mass of fresh leaf per unit area declined greatly, and the yield was significantly lower than CK. When pH was ≤2.5, the plant height was obviously lowered, and the visible injury on leaf surface was observed. Under acid rain stress, the contents of leaf chlorophyll a, chlorophyll b, and carotenoid, especially chlorophyll a, decreased obviously. Acid rain also suppressed the synthesis of soluble sugar and reduced sugar, and the suppression was stronger at pH≤3.5, and became much stronger with increasing acidity. The total free amino acid and soluble protein contents in leaves decreased with increasing acidity, and were significantly lower than CK when the pH was ≤3.5 and ≤4.5, respectively.

Key words: western mountainous China, ecosystem service, tradeoffs, synergies, Bailongjiang watershed of Gansu