Fractionaton Of Cu,Zn And Fe Isotopes During Absorption And Transportation In Higher Plants

Studies of non-traditional stable isotopes have being developed rapidly in recent years thanks to the introduction of multi-collector plasma-source mass-spectrometry(MC-ICPMS),and researches on copper,zinc,iron isotopes variations among the most non-traditional stable isotopes,in geochemistry,cosmochemistry and biogeochemistry.Elsholtzia Splendens was selected for in verst igat ion of Cu?Zn?Fe isotope fractionation in plant.The main achievements of the thesis are as followings:1.Cu isotopic variations of Cu in higher plant has been reported for the first time(?65Cuoverground part-root=-0.36?0.02‰??65Cu leaves-stem+branch=0.13-0.53‰),Elsholtzia Splendens are enriched in light Cu isotopes relative to soil(?65Cu the whole plant-soil=-0.28?-0.7‰).2.Isotopic variations of Zinc in plant has been proved further(?66Znovergound part-root=-0.36?0.11‰??66ZZn leaves-stem+branch ?-0.04?0.31 ‰),herbage are enriched in light Zinc isotopes compared to soil,and the isotopic variability is small(?66Znplant-soil=-0.06?-0.23‰).3.Isotopic variations of iron in higher plant has been proved further(A56Feoverground part-root 0.57?0.96‰?A56Fe leaves-stem+branch=-0.60?-0.25‰)and the range has been increased due to this research,Strategy ? plant are enriched in heavy Iron Isotopes compared to soil(?56Feplant-soil?0.20‰),The small enrichment of heavy isotopes is likely to be due to an equilibrium fractionation during complexation of Fe to phytosiderophores in the rhizosphere.4.Isotopic variations of Elsholtzia Splendens are effected by the growth term and the condition of the soil etc.5.Isotopic variations of plants and soil are controlled by both passive procedure-dynamicss(diffusive),and active procedure-thermodynamics(exchange reaction of copper,zinc and iron between different chelate complex-chemical equilibrium).In rhizosphere of soil,the fractionation of copper and zinc are likely to be controlled by mass flow,the fractionation of iron are likely to be controlled by active process.In plant,the fractionation of copper and zinc and iron are controlled by active transport mainly.