(A) Gas chromatography of alditol acetates of methylated sugars from laminarin (top) and cellulose (middle) standards and from the glucan purified from the ammonium oxalate fraction from shoots of rsw1 grown at 31°C (bottom). Coincident peaks show that the rsw1 glucan is 1,4-linked. (B through E) Roots frozen in nitrogen slush without cryoprotection were freeze-fractured with the use of double replica holders in a Balzers BAF 400T (18). (B) Normal microfibrils in rsw1 (18°C). (C) Rosettes (P face) of the mutant are indistinguishable from the wild type at 18°C, but (D) are rare and sometimes irregular in rsw1 seedlings within 3 hours of transfer to 31°C. (E) Particles in rows (arrows) can curve or cluster (box) under longer (18-hour) exposures. Scale bars, 50 nm. [from Arioli et al. 1998]