| With the continuous growth of population,the needs of national industrial and social development and the increase of a series of factors such as natural drought and water shortage,the phenomenon of water shortage is becoming increasingly serious.Therefore,the current situation of water shortage determines the necessity of drought resistant plants research in arid and semi-arid areas.Rose is one of the perennial woody flowers with high ornamental value and production value in the world.Drought stress is one of the most important factors restricting the growth of rose.It is of great significance to study the effect of drought stress on the growth of rose for water-saving planting and expanding the production and planting of rose in arid and semi-arid areas.In this experiment,"Fenghua 1" rose,"Fenghua 2" rose,"Russian White" rose and "Lengxiang"rose were taken as the research objects.Firstly,the drought resistance of edible rose varieties under different drought stress treatments were studied from different varieties and different degrees of drought stress.The physiological and biochemical indexes of four different edible roses varieties under drought stress were evaluated by laboratory identification method the changes of water physiology,cell membrane permeability,osmotic regulation system,antioxidant enzymes and chlorophyll system were analyzed.The membership function method and principal component analysis method are used for comprehensive evaluation.The main results were as follows:1.With the extension of drought stress time,the leaf water content and relative water content of four different varieties of rose showed a downward trend.The relative water content of "Fenghua 2"decreased by 1.73 times compared with the control,and the leaf water content decreased by 71.35%compared with the control.The variation trend of chlorophyll a,chlorophyll b and total chlorophyll content varied with different varieties.The chlorophyll a,chlorophyll b and total chlorophyll content of"Lengxiang" and "Russian White" showed an upward trend,while the chlorophyll a and total chlorophyll content of "Fenghua 1”and "Fenghua 2" showed an upward trend first and then a downward trend,However,the content of chlorophyll b showed the trend of first decreasing,then increasing and then decreasing,and the trend of first increasing and then decreasing.According to the analysis of the total chlorophyll content in leaves,"Fenghua 2" showed the worst performance.The total chlorophyll accumulation was 1.25 mg/g at 12 h of stress,which decreased by 0.54 mg/g compared with the control.The tolerance of "Lengxiang" and "Russian White" to drought stress was still within the tolerance range,which were 2.42 mg/g and 1.76 mg/g,respectively.The relative electrical conductivity and MDA content of all rose varieties showed an upward trend.Compared with the control,the relative electrical conductivity and MDA content of "Fenghua 2" leaves were the highest after 12 h stress,with the cumulative amounts of 73.16%and 35.39 μmol/g,respectively.The relative conductivity and MDA content of "Russian White" leaves were 31.14%and 24.06 μmol/g,respectively.Compared with CK,the water saturation deficit of "Fenghua 2","Fenghua 1","Russian White" and "Lengxiang" increased by 59.65%,99.19%,202.19%and 102.9%,and the soluble sugar content increased by 2.35%,1.37%,1.48%and 1.98%,respectively;Soluble protein showed two different trends under drought stress,and"Lengxiang" showed a trend of first decrease and then increase,while the other three varieties showed a trend of first increase,then decrease and then increase.At the later stage of drought stress,the increase of soluble protein content was the smallest,increased by 3.24 mg/g,3.35 mg/g,3.22 mg/g and 2.88 mg/g,respectively.Proline increased first and then decreased.When the stress reached 6 h,the rose content of "Fenghua 2","Fenghua 1","Russian White" and "Lengxiang" all reached their peaks,which were 563.38 μg/g,593.78 μg/g,444.58 μg/g and 638.37 μg/g,respectively,compared with the control,the increase was 129.68 μg/g,164.48 μg/g,92.97 μg/g and 184.06 μg/g,respectively;The proline content of "Fenghua 2","Fenghua 1","Russian White" and "Lengxiang" decreased after 12 h stress,but the accumulation was still higher than that of the control.The proline content of the four varieties was 2.18 times,2.09 times,2.85 times and 2.06 times higher than that of the control,respectively.SOD in the antioxidant enzyme system showed a continuous upward trend,POD showed a trend of first rising and then decreasing.At 12 h,SOD activity increased by 180.02%,116.96%,143.04%and 108.15%,POD activity increased by 7.25 times,3.17 times,2.51 times and 2.72 times.2.The principal component analysis was used to screen out 12 indexes,such as relative water content,water saturation deficit,leaf water content,relative conductivity,soluble protein,soluble sugar,malondialdehyde,proline,total chlorophyll,chlorophyll a,chlorophyll b and POD.The cumulative contribution rate of principal component reached 87.065%,which could be used as the drought resistance identification index of edible rose.3.According to the graph analysis of physiological and biochemical indexes and subordinate function analysis,the order of drought resistance of the four rose varieties from strong to weak was:"Lengxiang">"Russian White">"Fenghua 1”>"Fenghua 2". |
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