1993 Fiscal Year Final Research Report Summary

Studies on Boron Function and Distribution in Higher Plant Cells

Research Project

Project/Area Number	04660069
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	土壌・肥料
Research Institution	KYOTO UNIVERSITY
Principal Investigator	MATOH Toru Kyoto University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (50157393)
Project Period (FY)	1992 – 1993
Keywords	Boron / Boric acid / Pectic substances / Rhammnogalacturonan / Radish
Research Abstract	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.