Study Of Water Stress On Growth And Physiology Of Four Rosaceae Perennial Flowers

With the development of human society,people are increasingly pursuing a spiritual life,and their environmental requirements are increasing.As an important part of urban infrastructure,landscaping construction should maximize its ecological benefits and ornamental value,and should choose Plants suitable for environmental factors such as soil and climate in various regions.Therefore,the understanding of plant growth characteristics and stress resistance has become the focus of research.Perennial flowers breeding,ornamental and maintenance costs have certain advantages,and they have been liked and concerned by the public in landscaping.In this experiment,Geum aleppicum Jacq.,Potentlla chinensis Ser.,Potentilla bifurca L.And Sanguisorba officinalis L.were uesd as experimental materials.Physiological indexes of 4 kinds of perennial flowers at various drought stress points were determined by natural drought method;Physiological indexes of four kinds of perennial flowers at various water-stressed time points were measured by the immersion pot method.The membership function analysis method was used to compare the drought resistance and water resistance of the four plants.The specific research results are as follows:(1)Effects of natural drought stress on plants:With the prolongation of drought stress,the leaves of the four types of perennial flowers showed yellowing,wilt,and withering.Among them,Geum aleppicum Jacq.withered at 6 days stress.Under drought stress,the relative water content of leaves of all four plants showed a downward trend;Except for intercellular CO2,the four photosynthetic indicators showed a relatively stable trend,and the other three indicators showed a downward trend;Both proline content and malondialdehyde content increased with drought stress time;SP,SOD activity and POD activity all showed an"increasing-decreasing" trend.From the morphological changes and membership function analysis physiological index,it can be concluded that Potentilla chinensis Ser.has the strongest drought resistance,and Geum aleppicum Jacq.has the weakest drought resistance.(2)Effects of water flooding on plants:With the prolonged flooding time,the leaves of the four kinds of perennial flower plants all showed symptoms of blackening and wilting.Among them,new leaves of Geum aleppicum Jacq.and Potentilla chinensis Ser.in the early stage of flooding.But at the end of the 45day flooding period,the leaves turned black and wilted.Under water stress,the relative water content of the leaves of the four kinds of perennial flowers did not change significantly in the early stage of water flooding,and the decline was slow;Free proline content increased in the first and middle stages and slightly downward trend in the later period;The content of SP and soluble sugar,as well as the activity of SOD and POD,all showed an upward trend and then a downward trend;The content of malondialdehyde increased with the increase of the time of water flooding stress,gradually stabilized during stress 45d-60d;Combining the morphological changes and membership functions of four kinds of plants to analyze physiological indicators,it can be concluded that the Geum aleppicum Jacq.has the strongest water resistance,and the second column Potentilla bifurca L.has the least water resistance.(3)The drought resistance and waterlogging resistance of the four plants can be obtained through research as follows:The order of drought resistance is:Potentilla chinensis Ser.>Potentilla bifurca L.>Sanguisorba officinalis L.>Geum aleppicum Jacq.;the order of water resistance is:Geum aleppicum Jacq.>Potentilla chinensis Ser.>Sanguisorba officinalis L.>Potentilla bifurca L..According to the above ranking,the water adaptability of the four plants is as follows:Potentilla chinensis Ser.is highly adaptable to water,drought resistance and waterlogging resistance are strong;Potentilla bifurca L.has strong drought resistance,weak water resistance;Geum aleppicum Jacq.has weak drought resistance and strong waterlogging resistance;Sanguisorba officinalis L.is the least adaptable to water.