Fig. 3. Mycorrhizal root colonization of rice plants in the absence (C) or presence of 50 μM L−1 arsenate (AsV) and arsenite (AsIII) in the nutrient solution. The different letters indicate significant differences by Tukey’s test (5%) between the As treatments (C, AsV and AsIII). (The bars indicate the standard error, n = 4.) The photographs show the root segments that were colonized by the arbuscular mycorrhizal fungus and the fungal structures. (ARB: arbuscules; IRM; intraradical mycelial; ERM: extraradical mycelia; VES: vesicles.)Figure optionsDownload full-size imageDownload as PowerPoint slide
The arsenic concentration in the shoots and Tariquidar increased in the plants that were exposed to AsV and AsIII in the nutrient solution, and the As accumulation in plant tissues did not show significant differences between these plants; on average the As-exposed plants showed 5.3 μg g−1 dry weight basis of As. The metalloid was preferentially accumulated in the roots, with significantly higher As concentrations than in the shoots (Fig. 4). The arsenic concentration in the shoots was similar among the M and NM plants when AsV was added to the nutrient solution, whereas that in the roots was significantly higher in the NM than in the M treatments. Under AsIII exposure, the M plants showed higher As concentrations in both the shoots and roots than did the NM plants (Fig. 4).