Studies on Boron Function and Distribution in Higher Plant Cells

以萝卜根为原料，经分级、乙醇和甲醇/氯仿洗涤和冷冻干燥制备粗细胞壁。通过果胶酶消化和DEAE-Toyopearl、Superdex-75和DEAE-Sephacel上的柱层析，从粗萝卜细胞壁中溶解和纯化含硼多糖。纯化后的多糖分子量为7000，含糖量为糖醛酸52%、苦糖17.4%、半乳糖4.9%、鼠李糖9.8%，表明该含硼多糖为鼠李糖半乳糖酸。11B核磁共振显示，多糖的一个分子含有一个作为硼酸的硼分子。这种多糖中硼的回收率达到细胞壁硼的80%，表明硼几乎完全以这种多糖的结合形式存在于细胞壁中。我推测硼可能是通过与这种多糖结合来实现其功能的。

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.