title: Iodate and iodide effects on iodine uptake and partitioning in rice (Oryza sativa L.) grown in solution culture.
abstract: In the Xinjiang province of western China, conventional methods of iodine (I) supplementation (i.e, goiter pills and iodinated salt) used to mitigate I deficiencies were ineffectual. However, the recent addition of KIO3 to irrigation waters has proven effective. This study was conducted to determine the effects of I form and concentration on rice (Oryza sativa L.) growth, I partitioning within the plant, and ultimately to assist in establishing guidelines for incorporating I into the human food chain. We compared IO3- vs. I- in order to determine how these chemical species differ in their biological effects. Rice was grown in 48 L aerated tubs containing nutrient solution and IO3- or I- at 0, 1, 10, or 100 micromoles concentrations (approximately 0, 0.1, 1, and 10 mg kg-1 I). The IO3- at 1 and 10 micromoles had no effect on biomass yields, and the 100 micromole treatment had a small negative effect. The I- at 10 and 100 micromoles was detrimental to biomass yields. The IO3- treatments had more I partitioning to the roots (56%) on average than did the I- treatments (36%), suggesting differences in uptake or translocation between I forms. The data support the theory that IO3- is electrochemically or biologically reduced to I- prior to plant uptake. None of the treatments provided sufficient I in the seed to meet human dietary requirements. The I concentration found in straw at 100 micromoles IO3- was several times greater than seed, and could provide an indirect source of dietary I via livestock feeding on the straw.
authors.affiliation: Department of Plants, Soils, and Biometeorology, Utah State University, Logan, UT, USA. cmackow@cc.usu.edu
authors.forename: C L
authors.initials: CL
authors.lastname: Mackowiak
authors.forename: P R
authors.initials: PR
authors.lastname: Grossl
mesh_terms: D018533:Biomass; D003470:Culture Media / Q000493:pharmacokinetics; D004305:Dose-Response Relationship, Drug; D018527:Hydroponics; D007452:Iodates / Q000493:pharmacokinetics*; D007454:Iodides / Q000493:pharmacokinetics*; D007455:Iodine / Q000032:analysis / Q000378:metabolism*; D009753:Nutritive Value; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism*; D014867:Water / Q000378:metabolism
chemical_list: D003470:Culture Media; D007452:Iodates; D007454:Iodides; D014867:Water; D007455:Iodine