Study On High Temperature Stress Of Sedum Lineare ’JinYe’ And Sedum Spurium ’Coccineum’

The heat resistance of Sedum lineare ’JinYe’and Sedum spurium ’Coccineum’ under normal watering and drought condition were researched in order to extending their landscape application. The chlorophyll fluorescence parameters, relative chlorophyll content, relative conductivity, relative water content, and morphological characteristics were selected as factors for single factor experiments to study the physiological response and adaptive mechanism of the two sedum plants under the conditions of high temperature. The conclusions can be drawn as follows:(1) Chlorophyll fluorescence parametersFo value of Sedum spurium ’Coccineum’in 45℃ group reached maximum after high temperature treatment for 7 days with normal watering, while the Fo value of Sedum lineare ’JinYe’in 45℃ group reached maximum after high temperature treatment for 9 days. However, the Fo value of Sedum lineare ’JinYe’changed slightly and Fo value of Sedum spurium ’Coccineum’decreased after high temperature treatment. The Fo value of Sedum spurium ’Coccineum’and Sedum lineare ’JinYe’increased at early stage of high temperature treatment under drought condition. The Fo value of Sedum lineare ’JinYe’in 40℃ group started to decrease after high temperature treatment for 15 days, while the Fo value of Sedum spurium ’Coccineum’increased.The Fv/Fm value decreased at the whole stage of high temperature treatment under drought condition with normal watering.The qP value of the two plants decreased remarkably and decreased at the whole stage after high temperature treatment for 7 days under drought condition with normal watering.The ETR values of the two plants remarkably decreased compared with control group when the temperature higher than 35℃ after high temperature treatment for 7 days with normal watering. The ETR values of every groups decreased obviously compared to control group after high temperature treatment for 7 days under drought condition.The Fv’/Fm’ value of the two plants in 45℃ group decreased remarkably compared to control group after high temperature treatment for 7 days with normal watering. The Fv’/Fm’ value of Sedum lineare ’JinYe’started to decrease after high temperature treatment for 4 days under drought condition, while the Fv’/Fm’ value of Sedum spurium ’Coccineum’started to decrease after high temperature treatment for 7 days. The Fv’/Fm’ value of both the two plants decreased at the whole stage.(2) Relative chlorophyll contentThe relative chlorophyll content of the two plants decreased with high temperature treatment prolonging and normal watering. The relative chlorophyll content of the two plants changed with no remarkably law under drought condition.(3) Relative conductivityThe relative conductivity of Sedum lineare ’JinYe’changed slightly after high temperature treatment for 4 days with normal watering, while The relative conductivity of Sedum spurium ’Coccineum’started to increase. The relative conductivity of the two plants increased at the whole stage under drought condition.(4)Relative water content of leavesThe relative water content of the two plants leaves changed slightly with high temperature forcing and normal watering. The relative water content of Sedum lineare ’JinYe’leaves changed unobviously under drought condition, while the relative water content of Sedum spurium ’Coccineum’decreased with small degree.(5) Morphological characteristicsSmall section of Sedum lineare ’JinYe’leaves appeared yellowing and fading with high temperature forcing and normal watering. Most section of leaves in 45℃ group become wilting and sheding at later stage of high temperature treatment. The leaves of Sedum spurium ’Coccineum’appeared greening and wilting at early stage of high temperature stage and fading for most sections at later stage. The leaves of Sedum lineare ’JinYe’appeared yellowing, fading and partly wilting under drought condition with high temperature treatment, while the leaves of Sedum spurium ’Coccineum’appeared deeply purpling, wilting, even fading.(6) Sedum lineare ’JinYe’has better heat resistance than Sedum spurium ’Coccineum’(7) The application experiment results showed that Sedum lineare ’JinYe’and Sedum spurium ’Coccineum’can be applied in vertical planting, roof greening, outdoor wall greening, rock slope greening and flower bordering.