Study On The Effects Of Simulated Geological Storage CO₂ Leakage On The Growth Environment And Growth Effect Of Rice

CO₂ capture and storage?CCS?technology is currently an effective method to restrain the excessive growth of CO₂in the atmosphere.It is considered as the most promising and advantageous technology for the utilization and long-term storage of CO₂from large-scale emission sources.It's also an important measure to achieve a significant reduction of man-made CO₂emissions,and an effective mitigation of global warming.However,due to the unstable factors such as changes in technology and geological conditions during the implementation of the CCS project,there is still a risk of CO₂ leakage affecting the surface environment and ecology,which poses a huge threat to water environment,soil environment,plant growth and human health.Longjing 31 and Longdao 18 were taken as experimental objects,and box simulation technology was used to study the response of rice field water quality indexes(D_CO2?p H?DO and ORP),rice growth characteristics?Maximum root length,plant height,fresh weight,dry weight and total ear weight?and rice physiological indexes?Soluble proteins,antioxidant enzymes and MDA?to different geological storage CO₂ leakage rates,and to explore the effects of geological storage CO₂ leakage on rice growth environment and growth effects.The main conclusions are as follows:?1?Under the conditions of CO₂ leakage,the long-term changes of D_CO2,p H,DO and ORP in rice field water have an exponential function relationship with time.Among them,D_CO2and ORP are significantly positively correlated with CO₂ leakage rate,p H and DO are significantly negatively correlated with CO₂ leakage rate,and the equilibrium time of each water quality index decreases as the CO₂ leakage rate increases.After the balance of all indexes,the water quality indexes of paddy field water showed obvious diurnal variations,in which D_CO2was high in the morning and evening,and low in noon,while p H,DO and ORP were opposite.?2?Under CO₂ leakage conditions,the water quality indicators of paddy field water are significantly different from the control group.The differences in p H and ORP between the different CO₂ leakage rate groups are weak,and the differences between D_CO2and DO are significant.It is suggested that D_CO2in paddy field water should be taken as the main index of CO₂ leakage monitoring in paddy field system,and p H,DO and ORP should be used as the auxiliary indexes of CO₂ leakage monitoring.?3?The response of rice growth to CO₂ leakage was obvious.With the increase of CO₂ leakage rate,the maximum root length of the two rice varieties showed a trend of decreasing with the increase of CO₂ leakage rate,and with the extension of the penetration time of CO₂,the difference with control group was more significant.Under the CO₂ leakage rate of 0.48L·m^-2·min^-1,the maximum root length of Longjing 31 and Longdao 18 at harvest time decreased by 13.87%and 18.70%respectively compared with CK.With the increase of CO₂ leakage rate,the height of Longjing 31 increases first and then decreases,while that of Longdao 18 decreases.The biomass of the two rice varieties increased first and then decreased with the increase of CO₂ leakage rate.Under the CO₂ leakage rate of 0.06L·m^-2·min^-1,the biomass accumulation of rice was significantly promoted.When harvesting,the fresh weight,dry weight and total panicle weight of Longjing 31 and Longdao 18increased by 27.66%,33.35%,23.75%and 30.44%,34.00%,35.81%respectively compared with CK.In addition,at harvest time,Longdao 18 showed inhibition trend at 0.48 L·m^-2·min^-1CO₂ leakage rate,and its fresh weight,dry weight and total panicle weight decreased by2.51%,3.15%and 1.26%respectively compared with the control,while Longjing 31 showed no inhibition trend.?4?Under the condition of CO₂ leakage,the changes of osmotic regulation and antioxidant enzyme in rice metabolism are complex.In the early stage of CO₂ leakage,the soluble protein content,SOD and POD activity in the leaves of the two varieties of rice were increased,while the promoting effect was gradually weakened or even inhibited under the long-term leakage.CAT activity is more sensitive than the above three indicators.In addition to the improvement of CAT activity in the group with a small leakage rate within a certain leakage time,CAT activity starts to be inhibited under the condition of short-term CO₂ leakage with a large rate.With the extension of the life process of rice,both SOD and POD activity could maintain a high level and continue to exert resistance,while soluble protein and CAT activity gradually decreased,but did not reflect the difference in the effect of CO₂ leakage on this phenomenon.?5?Under the condition of CO₂ leakage,the variation amplitude of MDA content and CK in leaves of Longdao 18 was greater than that of Longjing 31and there is little difference in MDA content in leaves of Longjing 31.However,the MDA content of the 0.48 L·m^-2·min^-1CO₂ leakage rate group of Longdao 18 showed a trend higher than that of the control.The MDA content increased by 25.48%and 9.87%compared with the control at 56 days and 84days of ventilation.Based on the response trends of the two rice growth traits,it is preliminarily judged that both varieties have a certain tolerance to CO₂ leakage,and the tolerance threshold of Longjing 31 is slightly larger than that of Longdao 18.