| Green roof as the “fifth facade” of the city has attracted more and more attention because it can better coordinate the contradiction between the green area and the building area in the city.The existing light roof greening is mostly“a green”type.The landscape,the single material selection,the monotonous color,such roof greening can no longer satisfy people’s pursuit of human settlements,and the urban landscape with color sense,layering and artistic sense is more sought after by people,therefore,green plants on the roof In the process of breeding and research and development,in addition to breeding plants with excellent resistance,it is equally important to breed colorful leafy plants.In order to adapt to the water and light conditions in the habitat,plants have long formed their unique adaptation pathways to maintain their normal life activities.In this study,four species of comfrey plants were used for control experiments,by setting different water and Light gradient,analysis of leaf color changes,plant pigments,plant antioxidant system,plant osmotic adjustment,etc.of different plants under different water and light conditions,exploring different water and light treatments on four species of comfrey plants The main research results are as follows:1.Plant leaf color characteristicsDrought stress caused the Belosynapsis ciliata,Murdannia simplex to turn from green to red,Murdannia loriformis,and Callisia repens to change from green to yellowish green;shady treatment resulted in false purple evergreen,fine bamboo sedge leaf color From red to green,yoke grass,paved brocade grass leaves turn from green to yellow green.2,plant leaf pigmentUnder drought stress,the content of anthocyanin in Belosynapsis ciliata and Murdannia simplex increased significantly.There was no significant change in the content of anthocyanin in Murdannia loriformis and Callisia repens under different treatments.The drought stress caused chlorophyll content and carotenoids in four plants.The content was significantly reduced,and the carotenoid content ofBelosynapsis ciliata and Murdannia simplex decreased greatly.With the increase of shading degree,the content of anthocyanin in Belosynapsis ciliata and Murdannia simplex was significantly reduced,and shading treatment resulted in 4 kinds.The chlorophyll content of plants increased significantly,and the carotenoid content of Murdannia loriformis,and Callisia repens significantly increased.There was no significant change in the carotenoids of Belosynapsis ciliata and Murdannia simplex.3.Total antioxidant activity and protective enzyme activity of plantsDrought stress led to the increase of POD,SOD,CAT activity and total antioxidant activity of Belosynapsis ciliata and Murdannia simplex,while the Murdannia loriformis and Callisia repens showed a first up and then down trend,and the Belosynapsis ciliata and Murdannia simplex The total antioxidant capacity and protective enzyme activities of Valeriana under severe drought stress were higher than that of Murdannia loriformis and Callisia repens;shading treatment resulted in significant reduction of total antioxidant activity and protective enzyme activity of four plants,The reduction of Belosynapsis ciliata and Murdannia simplex were greater than that of Murdannia loriformis and Callisia repens.Under low light treatment,Murdannia loriformis and Callisia repens were under low light stress,and the total antioxidant capacity and protective enzyme activity increased.4.Plant anthocyanin-related enzyme activityDrought stress caused the activity of phenylalanine ammonia-lyase(PAL)in Belosynapsis ciliata and Murdannia simplex to increase continuously,and the activity of PAL in Murdannia loriformis and Callisia repens decreased continuously.The activity of enzyme(CHI)increased first and then decreased with the increase of drought stress.Under shading treatment,the activity of phenylalanine ammonia-lyase(PAL)and chalcone isomerase(CHI)were signifi-cantly decreased in 4 plants.Strong light can effectively induce the activity of PAL and CHI in Belosynapsis ciliata and Murdannia simplex.The activity of PAL is positively correlated with the content of anthocyanin in Belosynapsi s ciliata and Murdannia simplex.There was no correlation between the conten ts,and the CHI activity was not a simple linear relationship with the four plant anthocyanins.5.Plant osmotic adjustment substancesThe drought stress caused the MDA content of the four plants to increase continuously.The increase of Murdannia loriformis and Callisia repens was higher than that of Belosynapsis ciliata and Murdannia simplex,and the soluble sugar of Belosynapsis ciliata and Murdannia simplex decreased with the increase of drought stress.The content of soluble sugar in the Murdannia loriformis and Callisia repens increased continuously,and the soluble protein of the four plants increased with the increase of drought stress.With the decrease of light intensity,The Belosynapsis ciliata and Murdannia simplex aldehyde content decreased significantly,while the Murdannia loriformis and Callisia repens showed a trend of decreasing first and then increasing.The soluble sugar content of the four plants decreased significantly with the decrease of light intensity.The solubility in the leaves under different light treatments The sugar content is highest at higher light intensity and lowest at lower light.The soluble protein content of the leaves of the four plants had no significant changes under different light intensity treatments,and there was no significant difference in the soluble protein content of the leaves.6.Correlation analysis of physiological indicatorsThere was a positive correlation between the content of anthocyanins and the activities of flavonoids,total antioxidants,protective enzymes and anthoc yanin-related enzymes in Belosynapsis ciliata and Murdannia simplex,and neg-ative correlation with carotenoid content and MDA content.There was a posi tive correlation between chlorophyll and carotenoids and protective enzyme act ivities,and a negative correlation with MDA and soluble sugar content. |
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