Study On Absorption And Accumulation Characteristics Of Four Perennial Flowers To Lead And Cadmium

With Hemerocallis×hybrida‘stella deoro’,Hosta‘so sweet’,Hemerocallis fulva and Hosta ensata as test materials,under the treatment of the Pb 600mg/kg and the Cd 40mg/kg concentration.as the accumulation of lead and cadmium in plants with different time,we had a research of physiological growth response of the four kinds of materials. And overall evaluation their resistance by subordinate function method. Using the time Dynamics method to study the four flowers’ absorption characteristics to Lead and cadmium.Combining with subcellular fractionation and chemical speciation sequential extraction techniques to research subcellular distribution and chemical combined forms of lead and cadmium in four flowers’ above and under ground part.To investigate the mechanism of lead and cadmium tolerance and detoxification of the four flowers,and to provide a reference for the selection and application of urban greening plants.The results are as follows:(1)Besides increasing the height of Hosta ensata’ contrast and treatment and then decreased after the first show,the other three have been increasing.Increasing speed of root length significantly reduced and root length of treatments were lower than the contrasts’ with lead and cadmium accumulation in the plant.Which shows that growth and development of the four flowers would be affected when lead and cadmium accumulate to a certain extent.(2)Chlorophyll contents of the four perennial flowers have increased in a short lead accumulation time,but they began to decline along with the continuation of treatment time, chlorophyll content of Pb treatment were lower than the contrasts’.Indicating that short Pb treatment promoted chlorophyll synthesis.With the extension of cadmium stress time, four flowers showed no significant variation of chlorophyll content, which may be the result of different processing time cadmium and different plant maturity. Four floral chlorophyll content in lead and cadmium treatment in 64 days significantly were lower than the first day and the smallest decrease one is Hosta‘so sweet’.That’s means it has the strongest ability on lead and cadmium.(3)With the extension of Pb treatment time, SOD activity of four plants almost reduce after the first rise, and POD activity exhibited the trends of after the first lift; With increasing Cd treatment time, in addition to POD and SOD activity of Hosta ensata has been declining and relatively small the first day, other the latter three are the first increases and then decreases and finally higher than on the first day.Different plants’ POD and SOD activity are different magnitudes in different treatment of Cadmium. The effect of heavy metal to POD and SOD activity changes with the increasing of processing time, the increasing accumulation of heavy metals in plants causing more toxic to plants.(4) Overall evaluating four kinds s of perennial flowers by subordinate function method, the resistance of Pb and Cd from strong to weak as Hosta‘so sweet’,Hemerocallis×hybrida‘stella deoro’,Hemerocallis fulva, Hosta ensata. After comparing the heavy metal contents in four plants find that Pb accumulation capacity as Hosta‘so sweet’>Hemerocallis×hybrida‘stella deoro’>Hosta ensata>Hemerocallis fulva and Cd accumulation capacity as Hosta‘so sweet’ >Hemerocallis fulva>Hosta ensata>Hemerocallis×hybrida‘stella deoro’. From resistance and content of Pb and Cd can be seen: Hosta‘so sweet’ is a kind of high accumulation and high tolerant plants to heavy metals Pb and Cd,Hosta ensata is a kind of high accumulation and low tolerance plants.(5) For long time(0-40 days),the content of Pb and Cd in the underground part of four perennial flowers is more than that in aboveground portion.With increasing Pb and Cd treatment time,the four plants all emergence a maximum absorption content in the process.But the time of four flowers to reach absorption maximum are different.The transport coefficients of Hosta‘so sweet’ and Hemerocallis fulva for Pb significantly reduced when Hemerocallis×hybrida‘stella deoro’ and Hosta ensata increased first decreased;the transfer coefficient of the four flowers or Cd all reduced.(6) Subcellular distribution of lead in above and under ground parts of the four flowers is: the vacuolus and cellular soluble parts>the cell wall and its residue>the cell membranes and organelles,and subcellular distribution of cadmium is:the cell wall and its residue>the vacuolus and cellular soluble parts>the cell membranes and organelles. The part of the soluble and part of the cell vacuole containing Pb accounted for the largest part in above and under ground parts of the four flowers,about 42.91%-66.56%. The important part(48.64%-91.25%) of containing Cd is the part of the cell wall and the residue.(7)From the chemical forms distribution of lead can see: lead content of different chemical forms in above and below ground parts of Hemerocallis fulva descend to Pb HCl>Pb Na Cl>Pb W> Pb E>Pb HAc>Pbr and Hemerocallis × hybrida ‘ stella deoro ’ size Pb HCl>Pb HAc>Pb Na Cl>Pb W> Pb E>Pbr while Hosta‘so sweet’and Hosta ensata size Pb HCl>Pb W>Pb E>Pb Na Cl>Pb HAc>Pbr. Various chemical forms in above and below ground parts of Hemerocallis fulva,Hemerocallis×hybrida‘stella deoro’,Hosta‘so sweet’and Hosta ensata all are Pb HCl that accounted highest percentages 53.59% and 61.22%,42.82% and 42.67%,44.95% and 49.54%,56.45% and 37.17%.(8) From the chemical forms distribution of cadmium can know :cadmium content of different chemical forms in above and below ground parts of Hemerocallis fulva,Hemerocallis×hybrida‘stella deoro’and Hosta ensata descend to Cd E>Cd Na Cl>Cd W>Cd HAc>Cd HCl>Cdr when Hosta‘so sweet’ size Cd E>Cd W>Cd Na Cl>Cd HAc>Cd HC>Cdr.