KEYWORDS Fe oxide nanoparticles Iron deficiency Chlorosis in vitro Citrus volkameriana ABSTRACTPresent study was undertaken to explore of the effect iron nanoparticles (uncoated iron oxide nanoparticles, iron oxide nanoparticles coated with polyethylene glycol and FeEDTA and FeEDDHA chelates) on prevention of chlorosis in Citrus volkameriana. Study was carried out under the in vitro condition on MS medium supplemented with different iron compositions. Various growth attributes such as chlorophyll a, b, iron content of leaves, root and shoot length, number and area of leaves, degree of chlorosis, dry and fresh weights of seedling, roots and shoots were measured in end of study. Results of study revealed that seedlings grown on MS culture medium supplemented with uncoated nanoparticles of iron oxide had the highest rates of iron uptake and the lowest degree of chlorosis. Further, plant cultured on the MS medium with uncoated iron nanoparticles significantly increased vegetative growth characteristics such as, fresh and dry weights and chlorophyll content over the control (MS without chelated iron). Plant cultured on MS medium supplemented with uncoated iron oxide nanoparticles showed superiority over the plant cultured on MS media without iron and improved leaves growth characteristics and decreased chlorosis.