Transboundary air pollution has become a major environmental issue in Japan, while more serious air pollution has been simulated around the source area and the suburbs. Therefore, we investigated the responses to ozone increase and/or water shortage of plants growing in semiarid grasslands in Northeast China.
Shrubs (Artemisia halodendron, Caragana korshinskii, etc.) were grown in environment-controlled growth cabinets (14/10hrs (L/D), 25/15°C (L/D), 50/60%RH (L/D), 1,550μmol/m²/s (PPFD)) for 4weeks. Irrigation corresponding to precipitation (30, 60, 90, 120mm/month) was conducted every 2-3days (-15.2, -6.7, -3.1, -2.6kPa, respectively). An average of 50ppb (20-100ppb) or 0ppb ozone was exposed.
For A. halodendron, with increasing water stress and by ozone exposure, height growth was reduced and leaf withering was accelerated. New leaf emergence became the maximum with 90 mm irrigation and ozone tended to promote it.
For C. korshinskii, height growth became the maximum with 60-90mm irrigation and was reduced by ozone. Leaf withering was accelerated with increasing water stress and by ozone exposure, while new leaf emergence became the maximum with 90mm irrigation and ozone tended to suppress it.
The response to water and/or ozone stresses differed depending on shrub species. More precise investigation is required for future rehabilitation of desertificated semiarid grasslands.