Ornamental Evaluation And Drought And Flooding Tolerance Of Perennial Flowers In Chongqing Area

The thesis is based on the present situation of water resources shortage,abundant rainfall in rainy season,extremely imbalance precipitation in Chongqing.We preliminarily screened 26 species of perennial flowers suitable for the application of landscape in Chongqing,to observe their phenophase and evaluate their ornament.And then we conducted a research on water stress(drought tolerance and flooding tolerance)of 10 perennial flowers with high ornamental.Through ornamental evaluation and water stress research,we expected to screen out the perennial flowers with good performance in the open field planting in Chongqing,and also provide experience for the plant planting in drought and flooding environment.Results are as follows:1?Field planting and phenological observation of 26 perennial flowers were conducted to observe their germination stage,initial flowering stage,final flowering stage and wilting stage.The results showed that 19 of them were evergreen perennials,8 of them had significant wilting period,and 22 of them were flowering in spring,22 of them were flowering in summer,8 of them were flowering in autumn,3 of them were flowering in winter.2?The thesis established a comprehensive evaluation model suitable for the evaluation of perennial flowers in Chongqingthe by the Analsis Hierarchy Process(AHP).According to the actual distribution of comprehensive evaluation values and the results of field observations,the 26 perennial flowers are divided into 3 levels:Grade I(?3.0): perennial flowers with high ornamental value,totaling 10 varieties.Grade II(3.0~2.0): Perennial flowers with general ornamental value,totaling 13 varieties.Grade III(?2.0): Perennial flowers with poor ornamental value,totaling 3 varieties.It can be concluded that there are 10 species of perennial plants with high ornamental value in the open field planting in Chongqing,they were Hemerocallis fulva,Dianthus chinensis ‘thunderbolt',Tulbaghia violacea,Coreopsis basalis 'double sunburst',Iris tectorum ‘kobayashii',Salvia leucantha,Coreopsis basalis ‘sun kissed',Penstemon laevigatus subsp.Digitalis,Iris tectorum ‘louisiana',Tradescantia pallida,respectively.And the results can provide a certain basis for the introduction,popularization and application of perennial flowers in Chongqing.3?In the drought stress research,most varieties had changed a lot with the extension of the stress time,except for the leaves of Iris tectorum ‘louisiana' and Iris tectorum ‘kobayashii' blades.With the increase of stress,the SOD activity of 10 perennial flowers was on the rise,of some is rising first and then falling,among which the growth rate of Tulbaghia violacea Harv.,Iris tectorum ‘kobayashii',Iris tectorum ‘Louisiana' and Tradescantia pallida(Rose)D.R.Hunt is the fastest.The MDA content of 10 perennial flowers was also gradually rise,and all reached the maximum on the 8th day.The conductivity increased fastest in Salvia leucantha Cav.and Penstemon laevigatus subsp.Digitalis(Nutt.ex Sims)Bennett with the extension of the stress time,indicating that the drought tolerance of the two plants was weak.The drought tolerance of 10 perennial flowers was obtained by membership function method: Iris tectorum ‘louisiana'> Iris tectorum ‘kobayashii' > Tulbaghia violacea Harv.> Tradescantia pallida(Rose)D.R.Hunt > Hemerocallis fulva var.aurantiaca(Baker)M.Hotta>Coreopsis basalis ‘sun kissed'> Coreopsis basalis ‘double sunburst'> Dianthus chinensis ‘thunderbolt'> Penstemon laevigatus subsp.Digitalis(Nutt.ex Sims)Bennett > Salvia leucantha.4.In the flooding stress research,most plants had almost no significant change,the growth status was better,except Hemerocallis fulva var.aurantiaca(Baker)M.Hotta and Salvia leucantha Cav.,with an obvious change in leaves in late stage of experiment,indicating that most perennial flowers have a strong adaptability to flooding stress.The change of SOD activity in 10 perennial flowers was complex,some were gradually rising,while some were rising first and then decreasing.The MDA content of 10 perennial flowers was gradually rise,with the largest rising in Salvia leucantha Cav.and Hemerocallis fulva var.aurantiaca(Baker)M.Hotta,The conductivity showed different changes,showing an upward trend overall and a negative correlation between changes of conductivity value and flooding tolerance.The flooding tolerance of 10 perennial flowers was obtained by membership function method: Iris tectorum ‘louisiana'> Iris tectorum ‘kobayashii'> Tradescantia pallida(Rose)D.R.Hunt >Coreopsis basalis ‘double sunburst'>Tulbaghia violacea Harv.> Dianthus chinensis ‘thunderbolt'> Penstemon laevigatus subsp.Digitalis(Nutt.ex Sims)Bennett>Coreopsis basalis ‘sun kissed' > Hemerocallis fulva var.aurantiaca(Baker)M.Hotta > Salvia leucantha.