The Influence Of Ozone Stress On Physiological Function Of Grape Leaf

Under the background of global environmental change, the concentration of ozone (O3) is increasing constantly which caused obvious influence to crops including the grape. Ozone pollution has become an important factor affecting the development of agriculture. Therefore, the research on the harm and influence mechanism of ozone stress to grapes had great significance to guide culture practice and cultivate new varieties of ozone resistance.The suscepbility of three grape varieties to ozone stress were compared using open top chamber, The effct of ozone concentration on leaf physiological function of cabernet sauvignon and the combined effection of light intensity and ozone to grape leaf's physiological response were also studied. The research results are as follows:1. After treatment of ozone of 110 nl/L by 3h, the Fv/Fm of 5BB, cabernet sauvignon and frontanec were reduced by 6.6%,27.8% and 47.8% than controlm, respectively; the ABS/CSm was reduced by 9.1%,33.2% and 9.1%, respectively. Which indicated that the susceptiblity of the three grape varieties to ozone were as follow:frontanec>cabernet sauvignon>5BB.2. Under 55-105 nl/L ozone treatment, Pn reduced gradually with ozone concentration increasing, and was reduced by 17.9%?87.5% than control. The change trend of Gs was the same with Pn, and Ci was reduced first and then rised. Which indicated that under the stress of low concentration of ozone, the stomatal limitation is the dominant factor and with the increase of ozone concentration (>80nl/L), the limitation except stoma becomes the dominant factor.3. The influence of ozone stress on grape's photosynthetic function first characterized by inhibiting the electron transfer from body Qa - to QB.The concentration threshold is between 40 nl/L and 55 nl/L. With the increase of ozone concentration, the energy absorption of per unit area is reduced and the concentration threshold is between 55 and 80 nl/L.4. cpPS ? of grape leaf reduced gradually with ozone concentration increasing, NPQ increased first and then decreased. In the case of low concentration of ozone, the increasing of NPQ protected the photosynthetic mechanism by waste more excitation energy. Under the stress of high concentrations of ozone (105 nl/L), the structure relating to photochemical quenching was destroyed, which caused a decreasing tendency of NPQ. When the concentration of ozone is higher than 55nL/L,1-qP continues to increase with the increase of ozone concentration.5. The content of O2-, H2O2 and MDA in grape's leaf increased gradually with ozone concentration increasing. When the concentration of ozone more than a certain concentration between 55-80 nl/L, the content of Chl (a+b) gradually reduced.6. The enzyme activity of SOD and CAT increased gradually with ozone concentration increasing under the concentration of 40-80 nl/L. characterized by rising constantly. Uder the concentration of ozone by 105 nl/L, While the enzyme activity of SOD and CAT has a tendency to reduce when the ozone concentration higher than 105nL/L. The activity of POD decreased gradually with ozone concentration increasing.7. Under the stress of 105nL/L ozone, the shade alleviated the damage by ozone to grape leaf. Fv/Fm of the 1/3 and 2/5 shade treatment increased by 36.5% and 76.0% than control, and (pPS II increased by 113.6% and 136.0% than control.