Studies On The Ultra Weak Luminescence And Excitation Mechanism Regulation Of Reactive Oxygen Species Under Drought Stress In Sedum. Plants

The dynamic variation of ultraweak luminescence(UWL)and growth vigor,active oxygen system,photosynthetic characteristics,energy level and the relationship between them were studied during the simulated of PEG solution drought stress and active oxygen radical scavenger of hydrogen peroxide(H2O2)treatment and inducer of active oxygen species of sodium benzoate treatment under the simulated of PEG solution drought stress process in Sedum hybridum.The main research results were as follows:1.The UWL intensity of Sedum hybridum was related to drought stress.Under PEG simulated drought stress,the UWL intensity decreased and was lower than that of CK.which indicated that drought stress could affect UWL intensity.And under drought stress,plant growth activity decreased,O2-production rate,MAD content,relative electric conductivity increased,UWL was highly negative correlated with O2-production rate.MAD content,relative electric conductivity,and the difference was significant.The photosynthetic rate,chlorophyll a,chlorophyll b and total chlorophyll content decreased,UWL was positively correlated with photosynthetic rate,chlorophyll a,chlorophyll b and total chlorophyll content,and the difference was significant.The content of ATP decreased,the energy charge decreased,and the content of ADP and AMP increased,ATP and energy charge were positively correlated with UWL,and the difference was significant.These results indicated that accumulation of reactive oxygen species was not the direct source of UWL,and photosynthesis and energy levels were related to the production of UWL.2.Under PEG+H2O2 treatment,PEG+sodium benzoate treatment and PEG treatment(CK),the UWL intensity of Sedum hybridum decreased.O2-production rates,MDA content and relative electric conductivity of H2O2 treatment were all higher than those of CK but UWL intensity was lower than that of CK,and under H2O2 treatment,the photosynthetic rate,chlorophyll a,chlorophyll b and total chlorophyll content were lower than those of the CK,and the energy level represented by ATP was lower than that of the CK.While O2-production rates,MDA content and relative electric conductivity of benzoate treatment were all lower than those of CK but UWL intensity was higher than that of CK,and under sodium benzoate treatment,photosynthetic rate,chlorophyll a,chlorophyll b and total chlorophyll content were higher than those of CK,and ATP content was higher than that of CK.Under the active oxygen regulates drought stress,UWL was negative correlated with O2-production rate,MAD content,relative conductivity,and the difference was significant.Meanwhile UWL was positively correlated with photosynthetic rate,chlorophyll a,chlorophyll b and total chlorophyll content,and the difference was significant.UWL was also positively correlated with ATP and energy charge,and the difference were significant.The above results were further explained that reactive oxygen species was not the direct source of UWL,and that photosynthesis and energy levels were related to the production of UWL.