Studies on Boron Function and Distribution in Higher Plant Cells

以萝卜根为原料，经分级、乙醇、甲醇/氯仿洗涤、冷冻干燥等步骤制备粗细胞壁。通过果胶酶消化和DEAE-TOYOPERL、Superdex-75和DEAE-Sephacel柱层析，从萝卜粗细胞壁中溶解和纯化了含硼多糖。纯化后的多糖相对分子质量为7000，其中糖醛酸含量为52%，阿拉伯糖含量为17.4%，半乳糖含量为4.9%，鼠李糖含量为9.8%，表明该含硼多糖为鼠李半乳糖醛酸苷。~(11)B核磁共振分析表明，该多糖的一个分子中含有一个硼分子作为硼酸，该多糖中的硼的回收率达到了细胞壁中硼的80%，这表明硼几乎是以结合形式存在于细胞壁中的。我推测，硼可能是通过与这种多糖结合来发挥作用的。

Crude cell walls were prepared from radish roots with grading, ethanol- and methanol/chloroform-washing and freeze-drying. The boron-containing polysaccharide was solubilized and purified from the crude radish cell walls by pectinase digestion and subsequent column chromatography on a DEAE-Toyopearl, Superdex-75 and DEAE-Sephacel. The purified polysaccharide had a molecular weight of 7,000 and comprised of uronic acid 52%, abarinose 17.4%, galactose 4.9% and rhammnose 9.8%, suggesting the boron-containing polysaccharide was a Rhammnogalacturonan. One molecule of the polysaccharide contained one molecule of boron as boric acid, as revealed with 11B NMR.Recovery of boron in this polysaccharide amounted to 80% of the boron of the cell walls, indicating that boron occurs in cell walls as a bound form almost exclusively with this polysaccharide. I speculate that boron may fulfill its function through binding with this polysaccharide.