Secretion of malate and citrate from roots is related to high Al-resistance in Lespedeza bicolor

• Published in: Plant and soil Vol. 306; no. 1-2; pp. 139 - 147
• Main Authors: Dong, Xiao Ying, Shen, Ren Fang, Chen, Rong Fu, Zhu, Zhao Liang, Ma, Jian Feng
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.05.2008; Springer; Springer Netherlands; Springer Nature B.V
• Subjects: Acid soils; Acids; Agronomy. Soil science and plant productions; Al resistance; Aluminum; Animal, plant and microbial ecology; Anion-channel inhibitors; Anions; Anthracene; Biological and medical sciences; Biomedical and Life Sciences; Carboxylic acids; Citrate; Citrates; Ecology; Fundamental and applied biological sciences. Psychology; Lanthanum; Lespedeza; Lespedeza bicolor; Lespedeza cuneata; Life Sciences; Malate; Organic acids; Plant Physiology; Plant resistance; Plant roots; Plant Sciences; Plants; Regular Article; Root exudates; Roots; Secretion; Seedlings; Soil fertility; Soil Science & Conservation; Soils; Specific secretion; Studies; Citrate; Al resistance; Malate; Specific secretion; Anion-channel inhibitors; Soil plant relation; Lespedeza bicolor
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-008-9564-x

Lespedeza bicolor (Lespedeza bicolor Turcz. cv. Jiangxi) is a leguminous shrub that is well adapted to acid infertile soils. However, the mechanisms of aluminum resistance in this species have not been established. This study aimed to assess the possible resistance mechanisms of this plant to Al. An Al-sensitive species of Lespedeza, sericea lespedeza [Lespedeza cuneata (Dum.-Cours.) G. Don cv. Zhejiang], was used as a reference. The roots of L. bicolor secreted both malate and citrate after exposure to Al, but roots of L. cuneata did not. The secretion of organic acids from L. bicolor was specific to Al; neither 15-day P starvation nor 50 μM lanthanum induced the secretion of these organic acid anions. Secretion of organic acid anions in L. bicolor was detected after 3-6 h exposure to Al, and the amount increased significantly after 6 h exposure, suggesting that this plant shows a pattern II-type organic acid secretion. This is supported by the finding that the secretion was significantly inhibited by a protein-synthesis inhibitor, cycloheximide. Two kinds of anion-channel inhibitors had different effects on Al-induced secretion of organic acids: 9-anthracene carboxylic acid completely inhibited secretion, phenylglyoxal had no effect. Root elongation in L. bicolor was more severely inhibited by Al in the presence of 9-anthracene carboxylic acid. All these results indicated that the secretion of malate and citrate is a specialized response to Al stress in L. bicolor roots, which might be one of the Al-resistance mechanisms in this species.