تاثير برخي آمينواسيدهاي غالب در ريزوسفر بر جذب سيمپلاسمي و آپوپلاسمي كادميم و روي توسط ريشه و انتقال آنها به شاخساره گندم

چكيده انگليسي :

73 Effect of Some Dominant Amino Acids in the Rhizosphere onApoplastic and Symplastic Root Uptake and Translocation of Zinc and Cadmium in Wheat Kianoush Khodamoradi k khodamoradi89@yahoo com July 22 2014 Department of Soil Science Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor A H Khoshgoftarmanesh amirhkhosh@cc iut ac irAbstractZinc Zn is an essential micronutrient which its deficiency is widespread in wheat growing areas of theworld particularly in alkaline soils On the other hand cadmium Cd is a heavy metal that occursnaturally in soils and is readily taken up and accumulated by plants Similar geochemical andenvironmental properties of Cd and Zn may lead to their interaction during root uptake and translocationto shoot Root exudates greatly affect plant uptake transport from roots to aboveground parts andaccumulation of heavy metals in plant edible parts Among several substances identified in root exudates amino acids AA have drawn considerable interest due to their role in processes at the root soil interfacesuch as metal chelating We investigated the influence of histidine and glycine in nutrient solution onapoplastic and symplastic uptake and root to shoot translocation of Zn and Cd in a triticale xTriticosecale and a bread wheat cultivar Seedlings of the two species were grown in nutrient solutionsand exposed to two levels of Zn 0 and 10 M and two levels of Cd 0 and 1 M and either 50 Mhistidine 50 M glycine or no amino acids were added 4 weeks after germination Control plants weregrown with no such supply of Zn or Cd and amino acids All plants were harvested after 21d exposure tothe nutrient and treatment solutions Higher concentrations of Zn were found in wheat and triticale plantssupplied with Zn than in the control plants without Zn supply Among the treatments with Zn supply histidine enhanced while glycine reduced symplastic root Zn concentration in bread wheat Both aminoacids decreased the symplastic root Zn concentration but had no effect on apoplasmic Zn in triticale Bothamino acid treatments also reduced Zn concentrations in the xylem sap of the two plant species comparedto the treatment with Zn alone In bread wheat the effect was stronger for glycine than histidine intriticale it was the same for both amino acids The concentration of Zn in xylem sap was always greater inwheat than in triticale Nonetheless addition of histidine to the nutrient solution resulted in higher totalshoot Zn uptake in triticale but not in bread wheat as compared to the treatment with only Zn whileglycine had no significant effect on shoot Zn uptake in either of the two plant species The results showthat the ability of amino acids to enhance Zn uptake and translocation into the aboveground parts ofcereals is not necessarily related to increased xylem loading Histidine increased while glycine decreasedthe symplasmic apoplasmic and total root Cd concentration in wheat Both amino acids reduced total andsymplasmic Cd uptake in triticale While histidine had no effect on Cd concentration of xylem sap glycine increased it in wheat Both amino acids reduced Cd concentration in xylem sap of triticalecompared with amino acid free treatment Based on the results obtained the effect of amino acids on rootuptake and translocation of metals in plant is dependent on the amino acid type and plant species Keywords amino acids symplasm heavy metals apoplasm transport xylem sap

خدامرادي، كيانوش

تاثير برخي آمينواسيدهاي غالب در ريزوسفر بر جذب سيمپلاسمي و آپوپلاسمي كادميم و روي توسط ريشه و انتقال آنها به شاخساره گندم

فلزات سنگين , آوندچوبي