不同因子对荞麦中草酸含量的影响

Effect of Some Factors on Oxalate Content in Buckwheat Seedlings

用不同化合物从根部喂荞麦幼苗,测定其根叶中草酸含量的变化。结果表明:异柠檬酸、抗坏血酸及其前体物均可不同程度地降低荞麦根叶中草酸含量;而乙醇酸与乙醛酸则显著提高其草酸含量,表明荞麦叶片草酸合成主要来自乙醇酸途径,而非来自抗坏血酸等途径。水培条件下,以铵态氮或尿素等作唯一氮源时,荞麦中草酸含量远低于以硝态氮培养的;将谷氨酸或丝氨酸加到含硝态氮培养液中也能显著降低其草酸含量,不同氮素影响荞麦草酸含量可能与乙醇酸途径有关。

Buckwheat (Fagopyrum esculentum Moench) seedlings in Hoagland solution were fed with different substances, and oxalate contents in the roots and leaves were determined after 36 hours. The results showed that ascorbate and its precursors as well as isocitrate decreased to some extent the oxalate content in roots and leaves, whereas glycolate and glyoxylate significantly increased oxalate content, suggesting that oxalate in the leaves was synthesized mainly from glycolate pathway. Oxalate content in leaves of buckwheat seedlings cultured under hydroponic condition with ammonium nitrogen or urea as the only nitrogen source was much lower than that with nitrate nitrogen. The same result was observed under hydroponic condition with nitrate nitrogen in which glutamate or serine was added. It was shown that different nitrogen sources affecting oxalate accumulation in buckwheat leaves were closely related to glycolic acid metabolism.