Efforts Of Drought Resistance Characteristics And Mechanism Of The Compensation In Ulmus Parvifolia And Celtis Sinensis Seedlings

In this study,Ulmus parvifolia and Celtis sinensis seedlings are used to study the effects of different soil dry and wet treatments on the growth by pot experiment.In order to explore the drought resistance and resistance mechanism of Ulmus parvifolia Jacq and Celtis sinensis,the test studied their growth status,physiological and biochemical reactions,also provide theoretical basis and practical experience for further study on the stress resistance and compensation effect of woody plants.In this experiment,CK,T1,T2 and T3 were designed to analyze the number of dry and wet treatments in four different soils.Measured the growth status,photosynthetic parameters and chlorophyll fluorescence parameters,osmotic adjustment substances,MDA content,cell membrane permeability,protective enzyme activity and other physiological and biochemical indicators.The drought tolerance indexes and the drought tolerance of Ulmus parvifolia Jacq and Celtis sinensis were compared and analyzed by Excel and SPSS.Thought analysis the drought tolerance indexes and the drought tolerance for further research of ulmaceae plants dry-tolerance provided theoretical basis.Biomass,photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),chlorophyll fluorescence parameters,soluble protein,soluble sugar,Pro,MDA,membrane permeability,SOD,POD and other indexes were selected.Comprehensive analysis found that:Under the water stress,the growth status of Ulmus parvifolia Jacq and Celtis sinensis can reflect the drought tolerance of the tree species.Through the growth of the seedlings,the Celtis sinensis are more sensitive to water stress,and the Ulmus parvifolia Jacq of the resistance is relatively stable,stronger.The photosynthetic parameters and chlorophyll fluorescence parameters of the leaves were decreased in different stages,which indicated that the water stress affected thephotosynthesis of the plants.The results showed that the photosynthetic parameters and chlorophyll fluorescence parameters of the Celtis sinensis seedlings were significantly decreased,which the Ulmus parvifolia Jacq were more stable,indicate that the Celtis sinensis are more susceptible to water stress and are more sensitive to water stress,Ulmus parvifolia Jacq has a stronger drought resistance.With the alternation of dry and wet soil,the soluble protein,soluble sugar and Pro content of Ulmus parvifolia Jacq and Celtis sinensis seedlings increased sharply during drought,and decreased slowly after rewatering,and showed a general trend of increasing.It was found that the content of Pro was inversely proportional to the drought tolerance of the plant,that is the worse the drought tolerance of the plant,the more accumulation of Pro content.By comparison,it was found that the drought tolerance of the Ulmus parvifolia Jacq>the Celtis sinensis.The results showed that the content of MDA in the plant has a certain relationship with the cell membrane permeability.The higher the cell membrane permeability was,the higher the MDA content was.Drought stress resulted in increased MDA and cell membrane permeability.The results showed that MDA and cell membrane permeability of Celtis sinensis was higher than that of Ulmus parvifolia Jacq.Ulmus parvifolia Jacq has a stronger drought tolerance than the Celtis sinensis.The activity of SOD and POD in the Ulmus parvifolia Jacq and Celtis sinensis seedlings was increased and decreased with the wet and dry treatments,but it was significantly higher than that of CK,indicated that the activity of the enzyme play an important role in Ulmus parvifolia Jacq and Celtis sinensis physiological activities.Compared with the activity of the enzyme,the activity of Celtis sinensis enzyme was changed,Ulmus parvifolia Jacq enzyme was relatively stable,indicating that the Celtis sinensis are more sensitive to water and the Ulmus parvifolia Jacq drought resistance are stronger.Plant single traits or an indicator of the determination of the results,it is difficult to accurately reflect the degree of drought tolerance of plants,need for comprehensive evaluation of a number of physiological indicators and the indicators prevail.Comprehensive analysis of multiple physiological indicators found: the drought resistance of Ulmus parvifolia Jacq> Celtis sinensis.