Effects of salt and alkali stress on growth, accumulation of oxalic acid, and activity of oxalic acid-metabolizing enzymes in Kochia sieversiana

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• 作者：Y. Ma ; X. P. Wang ; S. F. Zhang ; D. C. Shi ; L. X. Sheng
• 关键词：Additional key wordsascorbic acid ; glycolate oxidase ; oxalate oxidase ; phosphoenolpyruvate carboxylase
• 刊名：Biologia Plantarum
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：60
• 期：4
• 页码：774-782
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Sciences;
• 出版者：Springer Netherlands
• ISSN：1573-8264
• 卷排序：60

文摘

Kochia sieversiana (Pall.) C.A. Mey. is a forage plant that can grow in extremely alkalinized grasslands at pH 10 or higher. Accumulation of a large amount of oxalic acid (OxA) is a primary characteristic of K. sieversiana. In our study, seedlings of K. sieversiana were exposed to the following conditions: non-stress, salinity (200 mM, a molar ratio of NaCl and Na₂SO₄ 1:1), and alkali stress (200 mM, a molar ratio of NaHCO₃ and Na₂CO₃ 1:1). Growth, water content, content of organic acids (including OxA), Na+, and K+, and activities of some OxA metabolism-related enzymes were determined. Results show that glycolate oxidase was the key enzyme for OxA synthesis; however, the carboxylation of phosphoenolpyruvate (PEP) by PEP carboxylase (PEPC) probably played a minor role in the OxA-synthetic pathway. The pathway of L-ascorbic acid catabolism was not the main source of OxA accumulation, and the activity of oxalate oxidase (OxO) involved in OxA decomposition was not a limiting factor for inner OxA accumulation. Taken together, accumulation of a large amount of OxA are not related to the degradation and secretion function of OxO but largely depend upon its synthetic function.