NEUTRON-DIFFRACTION AND PROTON NUCLEAR-MAGNETIC-RESONANCE - COMPLEMENTARY PROBES OF IN-SITU CELLULOSE DIMENSIONS AND PRIMARY PLANT-CELL WALL STRUCTURE

Neutron diffraction was used to monitor the microscopic structure of c ell walls from etiolated bean (Phaseolus vulgaris L.) hypocotyls after successive chemical fractionations with ammonium oxalate - oxalic aci d and potassium hydroxide. Wide angle neutron scattering measurements showed that there was no highly ordered long range structure and confi rm results from proton nuclear magnetic resonance techniques that ther e is alteration of the cell wall cellulose by chemical fractionations. Small angle scattering measurements showed that the residual cellulos e microfibrils increased in diameter from 75.0 +/- 2.3 to 110.0 +/- 4. 2 Angstrom (1 Angstrom = 0.1 nm) after successive treatments with ammo nium oxalate - oxalic acid and potassium hydroxide. The technique has potential applications to study cellulose dimensions in situ.