Iodate and iodide effects on iodine uptake and partitioning in rice (Oryza sativa L.) grown in solution culture

• Published in: Plant and soil 1999, Vol.212 (2), p.135-143
• Main Authors: Mackowiak, C.L. (Utah State Univ., Logan, UT (USA). Dept. of Plants, Soils and Biometeorology), Grossl, P.R
• Format: Article
• Language: English
• Subjects: Agricultural soils; Agronomy. Soil science and plant productions; Biological and medical sciences; Biomass; CARENCE DU SOL; CULTIVO HIDROPONICO; CULTURE HYDROPONIQUE; Culture Media - pharmacokinetics; DEFICIENCIAS DEL SUELO; Dose-Response Relationship, Drug; Feed and pet food industries; Food industries; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Generalities. Production, biomass, yield. Quality; Human physiology applied to population studies and life conditions. Human ecophysiology; HYDROPONICS; Iodates - pharmacokinetics; IODE; IODIDES; Iodides - pharmacokinetics; IODINE; Iodine - analysis; Iodine - metabolism; IODURE; Medical sciences; Nutrient solutions; Nutritional survey. Food supply and nutritional requirement; Nutritive Value; Oryza - growth & development; Oryza - metabolism; ORYZA SATIVA; Plant roots; Plant Roots - growth & development; Plant Roots - metabolism; Plants; Rice; Seeds; Seeds - growth & development; Seeds - metabolism; Short Communication; SOIL DEFICIENCIES; Space life sciences; Water - metabolism; Water treatment; YODO; YODUROS
• ISSN: 0032-079X; 1573-5036

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 $IO_3^ - $ 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 $IO_3^ - $ or I⁻ at 0, 1, 10, or 100 µM concentrations (approximately 0, 0.1, 1, and 10 mg kg⁻¹ I). The $IO_3^ - $ at 1 and 10 µM had no effect on biomass yields, and the 100 µM treatment had a small negative effect. The I⁻ at 10 and 100 µM was detrimental to biomass yields. The $IO_3^ - $ 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 $IO_3^ - $ 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 µM $IO_3^ - $ was several times greater than seed, and could provide an indirect source of dietary I via livestock feeding on the straw.