Search

To investigate the effects of aluminum stress on root exudates of Helianthus tuberosus and the alleviating effect of exogenous salicylic acid(SA), we used aluminum-tolerant Nanjing H. tuberosus and aluminum-sensitive Ziyang H. tuberosus as experimental materials and set aluminum concentration of 500 μmol·L-1 by soil culture method, and analyzed the effects of different concentrations(10, 100, 1 000 μmol·L-1)of SA on the organic acids and amino acids in root exudates of H. tuberosus and related metabolic enzymes in root tips under aluminum stress. The results were as follows:(1)Concentrations of citric acid, oxalic acid and malic acid in the root exudates of H. tuberosus increased under single Al stress, and the increase was greater in Nanjing H. tuberosus than in Ziyang H. tuberosus; The activities of citrate synthase and malate dehydrogenase increased under single Al stress; The proline content increased significantly, and the concentration of total amino acids decreased significantly.(2)The concentrations of citric acid, oxalic acid and malic acid secreted by the root system ofNanjing H. tuberosus were increased to different degrees after the addition of exogenous SA, but the oxalic acid secreted by the root system of Ziyang H. tuberosus was significantly reduced after treatment with high concentration(1 000 μmol·L-1)of SA, and there was no significant change in malic acid concentration under all concentrations of SA treatment; The citrate synthase activity appeared to be enhanced to different degrees, but it had little effect on malate dehydrogenase activity in the root tips of Nanjing H. tuberosus, and malate dehydrogenase activity in the root tips of Ziyang H. tuberosus was significantly reduced after treatment with high concentration(1 000 μmol·L-1)of SA; The proline content decreased significantly, from terms of changes in total amino acid concentration, the maximum alleviating effect was obtained at high concentration(1 000 μmol·L-1)SA for Nanjing H. tuberosus and at low concentration(10 μmol·L-1)SA for Ziyang H. tuberosus. Therefore, H. tuberosus responds to aluminum toxicity by secreting organic acids, and exogenous SA can promote the rate of organic acid metabolism in the root system of H. tuberosus to secrete more organic acids to alleviate aluminum stress, and this alleviation effect is better in Nanjing H. tuberosus, which is relatively strong in aluminum tolerance. [ABSTRACT FROM AUTHOR]

Copyright of Progress in Modern Biomedicine is the property of Publishing House of Progress in Modern Biomedicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)