Influences Of Different Types Of Acid Stress On The Resistant Physiology In Picea Asperata And Lolium Multifolorum

China is the third largest acid rain area in the world. With the development of industry in our country, the increasing proportion of NOx pollution has offset the effect of pollution controlling in SO2 on a certain extent, and result in the pollution type changed from the previous sulfuric-rich acid into the sulfuric-nitric mixed acid rain gradually. However, the systematic researches on the influences of varied acid rain types on plant harming mechanism are still scarce. Co element is considered to be one of the beneficial elements during plant growth and development, the researches on Co physiological role during acid stress and its implications are also relatively less. In this paper, both the effects of different types of simulated acid rain stress on spruce, and the phsiological role of CoCl2 on Lolium multiflorum seed's germination and seedling's growth during acid stress are systematicly investigated.The first part of this study aimed at the resistant physiology of the vitro spruce leaves which were treated with the simulated solution of sulfuric-rich acid rain (SAR), mixed acid rain (MAR) and nitric-rich acid rain (NAR).The results showed that: With the decline in acid solution pH value, the O 2? production rate, H2O2 and MDA content increased markedly, while the content of the MSI, chlorophyll and carotenoid decreased, the activities of antioxidant enzyme and the content of soluble sugar and proline increased and then decreased. Compared the injury levels of these three types of simulated acid rain to spruce, we found that NAR was much higher damage than the MAR and SAR, this may relate to the stronger oxidation of dilute nitric acid compared with dilute sulfuric acid.In the second part, the Lolium multiflorum which was dipped in different CoCl2 concentrations had been chosen as the experimental material, the influence on seed germination and seedling growth were studied after the treatment of acid stress.The results indicated that there was no significant influence on Lolium multiflorum seed germination and seedling growth when CoCl2 concentration was 0.01mmol/L.0.1mmol/L CoCl2 treatment under acid rain decreased the MSI, O 2? production rate, H2O2, MDA content, POD activity. Meanwhile, it improved Lolium multiflorum seed germination significantly, and it alleviated the acid rain stress on the Lolium multiflorum seeds and seedlings. 1.0mmol/L CoCl2 increased the seed germination ability, stem length, dry weight of the lower floor, MSI, and SOD activity during the pH3.0 acid treated, reduced the production rate of O 2? and H2O2 content, however, the root length inhibition index, chlorophyll content and MDA content had no obviously response to this treatment.In conclusion, different types of acid stress existed discrepancy in resistance physiology of vitro spruce leaves at low pH levels.The damage caused by NAR stress acidity (when it was pH2.0, pH1.0) on spruce leaf was bigger than SAR and MAR. (2) Compared the influence of the Lolium multiflorum seed germination and seedling caused by different concentrations CoCl2 and acid stresses, we found that: Lolium multiflorum seed pretreated in low CoCl2 concentration could enhance the seed germination when it grew under the acid rain obviously, it can also relieve the adverse effects on Lolium multiflorum seed germination and seedling growth which were caused by acid rain. The most obviously effect obtained when 0.1mmol/LCoCl2 treated.10mmol/LCoCl2 and acid stress synergistic inhibited Lolium multiflorum seed germination and seedling growth.