biologia plantarum

Biologia plantarum 51:791-794, 2007 | DOI: 10.1007/s10535-007-0162-1

Root morphology and cadmium uptake kinetics of the cadmium-sensitive rice mutant

J. Y. He¹, C. Zhu^1,*, Y. F. Ren², D. A. Jiang², Z. X. Sun³

¹ College of Life Science, Zhejiang University, Hangzhou, P.R. China

² College of Life Science, South China Agriculture University, Guangzhou, P.R. China

³ China National Rice Research Institute, Hangzhou, P.R. China

To understand the physiological mechanism that confers Cd sensitivity, root morphology and Cd uptake kinetics of the Cd-sensitive mutant and wild type rice were investigated. The root length, root surface area, and root number of mutant rice decreased more significantly with increasing Cd concentration in growth media compared with the wild type rice. The uptake kinetics for ¹⁰⁹Cd²⁺ in roots of both the mutant and wild type rice were characterized by a rapid linear phase during the first 6 h and a slower linear phase during the subsequent period. Concentration-dependent Cd²⁺ influx in both species could be characterized by the Michaelis-Menten equation, with similar apparent K_m values for mutant and wild type rice (2.54 and 2.37 µM, respectively). However, the V_max for Cd²⁺ influx in mutant root cells was nearly 2-fold higher than that for wild type rice, indicating that enhanced absorption into the root is one of the mechanisms involved in Cd sensitivity in mutant rice.

Keywords: Oryza sativa; Cd-accumulation; Cd-translocation

Subjects: cadmium; metals; mutagenesis, mutants; Oryza sativa; rice

Received: January 4, 2006; Accepted: August 15, 2006; Published: December 1, 2007  Show citation