The Influence Of Drought Stress On Plants Methane Emissions

As the second most important greenhouse gas after carbon dioxide,methane play an important role in the greenhouse effect.Although there were controversies on whether terrestrial plants emit methane under aerobic conditions,more and more researches confirmed that terrestrial plants themselves did emit methane,and most of the methane was produced under stress constitutions.In this study,we observe the methane emission of Cunninghamia lanceolata and Castanopsis carlesii under drought stress by potted simulation experiments,and discuss the mechanism of methane emissions.We discussed the source of methane emit from Cunninghamia lanceolata and Castanopsis carlesii under drought stress.At last,we attempted to verify the important role of reactive oxygen(ROS)in methane emit from plants by ROS generator experiments and ROS scavenger experiments.The main conclusions that we concluded as follows:(1)The emission rates of Cunninghamia lanceolata and Castanopsis carlesii increased significant under drought stress,and it increased significant with the increase of drought level and extension of time.(2)under drought stress,the physiological ecology characteristics of plants influence the methane emission of Cunninghamia lanceolata and Castanopsis carlesii,and the ROS and MDA of leaves play a positive role to increase the methane emission,while the role of protective enzyme system of the leaves organization were not significant.(3)There were significant differences in the stable carbon isotopic value of labeled and unlabeled leaves between Cunninghamia lanceolata and Castanopsis carlesii,the stable carbon isotopic value(?13C)of the labeled Cunninghamia lanceolata and Castanopsis carlesii leaves was 13.53 and 11.83 times than unlabeled ones.The stable carbon isotopic value of methane(?13CH4)isotopic signatures of methane,which emitted from Cunninghamia lanceolata and Castanopsis carlesii were 1.58 and 1.63 times higher than that of the unlabeled ones.The ?13CH4 of methane increased significant under drought stress,and it increased significant with the increase of drought level and extension of time.Cultivated 36 hours,the ?13CH4 of methane from the soil decreased significant as well as the methane emission rate.(4)Due to ROS generator experiments and ROS scavenger experiments,We verified that increase hydrogen peroxide(H2O2)concentration stimulate the methane emission of plants,while ROS scavenger restrain methane emit from plants.