title: DNA-protein cross-links involved in growth inhibition of rice seedlings exposed to Ga.
abstract: Hydroponic experiments were conducted with rice seedlings (Oryza sativa L. cv. XZX45) exposed to gallium nitrate (Ga(3+)) to investigate the accumulation of Ga in plant tissues and phytotoxic responses. Results showed that phyto-transport of Ga was apparent, and roots were the dominant site for Ga accumulation. The total accumulation rates of Ga responded biphasically to Ga treatments by showing increases at low (1.06-8.52 mg Ga/L) and constants at high (8.52-15.63 mg Ga/L) concentrations, suggesting that accumulation kinetics of Ga followed a typical saturation curve. Higher amount of Ga accumulation in plant tissues led to significant inhibition in relative growth rate and water use efficiency in a dose-dependent manner. DNA-protein cross-links (DPCs) analysis revealed that overaccumulation of Ga in plant tissues positively stimulated formation of DPCs in roots. Likewise, the measure of root cell viability evaluated by Evan blue uptake showed a similar trend. These results suggested that Ga can be absorbed, transported, and accumulated in plant materials of rice seedlings. Overaccumulation of Ga in plant tissues provoked the formation of DPCs in roots, which resulted in cell death and growth inhibition of rice seedlings.
authors.affiliation: The Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, College of Environmental Science & Engineering, Guilin University of Technology, Guilin, 541004, People's Republic of China, yuxiaozhang@hotmail.com.
authors.forename: Xiao-Zhang
authors.initials: XZ
authors.lastname: Yu
authors.forename: Xue-Hong
authors.initials: XH
authors.lastname: Zhang
mesh_terms: D018744:DNA, Plant / Q000737:chemistry / Q000378:metabolism; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D005708:Gallium / Q000378:metabolism / Q000633:toxicity*; D018527:Hydroponics; D012275:Oryza / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism
chemical_list: D018744:DNA, Plant; D004785:Environmental Pollutants; D010940:Plant Proteins; D005708:Gallium; C027235:gallium nitrate