Changes Of Ultraweak Luminescence In Cerasus Humilis And The Relationship Between Ultraweak Luminescence And Photosynthesis Under Drought Stress

In this experiment,the 'Mongolian' Cerasus humilis were used as the test material.The ultraweak luminescence(UWL),photosynthetic capacity,photosystem activity and photoenergy distribution,and photosynthetic pigment in Cerasus humilis were studied under drought stress and inhibition of photosystem activity under drought stress,to explore the relationship between ultraweak luminescence and photosynthesis and the mechanism of ultraweak luminescence.The main results of this study were as follows:1.The UWL intensity in leaves of Cerasus humilis was related to drought stress.Under drought stress,with the deepening of stress,the ultraweak luminescence of Cerasus humilis leaves decreased and was lower than that of the control,indicating that drought stress would lead to the decrease of ultraweak luminescence intensity in the leaves of Cerasus humilis,Ultraweak luminescence can reflect the degree of drought stress on plants.2.The UWL intensity in leaves of Cerasus humilis was related to photosynthesis.Under drought stress,with the deepening of stress,the photosynthetic system activity and light energy allocation index decreased,photosynthetic pigment content increased as a whole,chlorophyll a/b decreased,photosynthetic efficiency decreased,and ultra-weak luminescence intensity decreased;The ultra-weak luminescence intensity was highly positively correlated with the actual photochemical efficiency,moderately positively correlated with the antenna conversion efficiency,and moderately positively correlated with chlorophyll a/b in the leaves of Cerasus humilis,moderately negatively correlated with chlorophyll a content,chlorophyll b content and chlorophyll a+b content,highly positively correlated with transpiration rate,and moderately positively correlated with stomatal conductance and net photosynthetic rate,indicating that photosynthesis was related to the production of ultraweak luminescence.3.Under drought stress,under further inhibition of photosystem activity treatment,with the deepening of stress,the activity of photosystem decreased and the index of distribution of light energy decreased.The photosynthetic pigment showed an overall upward trend,the photosynthetic efficiency decreased,and the intensity of ultraweak luminescence showed a downward trend.The intensity of ultraweak luminescence was highly positively correlated with the actual photochemical efficiency and moderately positively correlated with the conversion efficiency of the antenna,the content of chlorophyll a and chlorophyll a+b were negatively correlated with ultraweak luminescence.The relationship between ultraweak luminescence and chlorophyll b?chlorophyll a/b content was very weak.Ultraweak luminescence was highly positively correlated with transpiration rate,and moderately positively correlated with stomatal conductance and net photosynthetic rate,which further indicated that photosynthesis was related to the production of ultraweak luminescence.4.Chloroplast had ultraweak luminescence phenomenon,and its ultraweak luminescence intensity decreased when the chloroplast function was inhibited,which indicated that chloroplast was one of the organelles that produced ultraweak luminescence phenomenon in leaves.