Plant Root
Online ISSN : 1881-6754
ISSN-L : 1881-6754
Published on May 22, 2015
Exudation of fumarate from roots contributes to high aluminum resistance in Melaleuca cajuputi
Akira NoguchiYoshifumi HoumanFumie ShinmachiRong Fu ChenXue Qiang ZhaoRen Fang ShenIsao Hasegawa
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2015 Volume 9 Pages 15-23


Two Melaleuca species, M. cajuputi and M. bracteata, were compared to identify the factors determining their distinct aluminum (Al) resistance levels. The presence of Al in a liquid culture medium (maximum tested concentration, 2 mM) did not affect the growth of M. cajuputi, but severely inhibited the growth of M. bracteata. The Al content in the roots was 50% higher in Al-sensitive M. bracteata than in Al-resistant M. cajuputi. Al penetration and tissue damage were obvious in the roots of M. bracteata, but only mild in the roots of M. cajuputi. Relatively high levels of fumarate were released by the roots of M. cajuputi, but not by those of M. bracteata. Supplementation of Al-containing liquid media with fumarate resulted in a reduction of Al toxicity on M. bracteata. These results suggest that Al-resistant M. cajuputi releases fumarate from its roots, thereby detoxifying Al.

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© 2015 Japanese Society for Root Research
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