IMPACTS OF OZONE CONCENTRATION CHANGES ON CROPS AND VEGETABLES IN CHINA

The controlled simulation experiments revealed that ozone concentration increases cause various degrees of injury to leaves of crop and vegetable.The injury to vegetables is greater than that to crops.Ozone can dramatically affect stomatal conductance,photosynthetic rate and transpiration rate,and consequently the yield of crops.No matter how long exposure time was, stomatal conductance increased and photosynthetic and transpiration rates decreased with increases in ozone concentration.When ozone concentration was 100 nmol/mol,yields of rice and winter wheat declined by 27.1% and 60.5% respectively.When up to 200 nmol/mol,there was a significant reduction of yields:a decline up to 33.7% for rice and 81.3% for winter wheat.On the other hand,ozone benefits the improvement of grain quality such as amino acid and protein.