光照强度对小麦苗期草酸氧化酶活性的影响

Oxalate Oxidase Activities of Wheat Seedlings under Different Light Intensities

以小麦品种‘烟优361’(Triticum aestivum L.cv.Yanyou 361)萌发4 d幼苗为试验材料,分析了草酸氧化酶(OxO)在幼苗中的定位和表达,以及光照强度处理对小麦幼苗OxO活性的影响。实验结果显示,萌发后小麦幼苗的OxO分布在子叶与根的连接处和成熟的根中,其活性随光照强度的增加而下降;200μmol.m-2.s-1的强光显著抑制了OxO活性,该处理培养4 d幼苗的OxO活性仅为40μmol.m-2.s-1光照培养条件下的18.7%;强光还缩短OxO在苗期的表达时间,抑制了OxO的mRNA表达量。同时,光照强度还能影响小麦幼苗中H2O2的含量,200μmol.m-2.s-1处理幼苗的H2O2的含量显著下降,其培养4 d的幼苗H2O2含量仅为40μmol.m-2.s-1光照强度培养条件下的18.0%。研究发现,光照强度可通过调节OxO的活性和表达量来控制H2O2的产量,从而影响幼苗的生长发育。

Wheat（Triticum aestivum L.cv.Yanyou361） seedlings were cultured under different light intensities to study the effects on the oxalate oxidase activities.The results showed that the oxalate oxidase of wheat seedlings distributed in the junction of cotyledon and root and distributed in the mature root.The oxalate oxidase activities decreased with the increase of light intensities.200 μmol·m-2·s-1 light intensities significantly inhibited the oxalate oxidase activities.The oxalate oxidase activity of 4 d seedlings cultured under 200 μmol·m-2·s-1 was only 18.7% of that cultured under 40 μmol·m-2·s-1 light intensity,the oxalate oxidase expression time was also shortened in the seedling stage,and the mRNA expression of the oxalate oxidase was inhibited.The H2O2 contents of wheat seedlings were affected by the light intensities,decreasing under the high light intensities and the H2O2 content of 4 d seedlings cultured under 200 μmol·m-2·s-1 was only 18.0% of that cultured under 40 μmol·m-2·s-1 light intensity.Based on these results,we conclude that the light intensities affect the seedlings growth by adjusting the OxO activities and expressions to control the H2O2 outputs.