Geometric and crystallographic measurements of grain‐boundary thermal grooves and surface faceting behavior as a function of orientation have been used to determine the surface energy anisotropy of SrTiO3 at 1400°C in air. Under these conditions, thermal grooves are formed by surface diffusion. The surface energy anisotropy was determined using the capillarity vector reconstruction method under the assumption that Herring's local equilibrium condition holds at the groove root. The results indicate that the (100) surface has the minimum energy. For surfaces inclined between 0° and 30° from (100), the energy increases with the inclination angle. Orientations inclined by more than 30° from (100) are all about 10% higher in energy and, within experimental uncertainty, energetically equivalent. A procedure for estimating the uncertainties in the reconstructed energies is also introduced. Taken together, the orientation dependence of the surface‐facet formation and the measured energy anisotropy lead to the conclusion that the equilibrium crystal shape is dominated by {100}, but also includes {110} and {111} facets. Complex planes within about 15° of {100} and 5° of {110} are also part of the equilibrium shape.

Measurements of the grain boundary population as a function of misorientation and boundary plane orientation show that the distribution is inversely correlated to the sum of the energies of the surfaces comprising each boundary. The observed correlation suggests that the difference between the energy of a high‐angle grain boundary and the two component surfaces is relatively constant as a function of misorientation. Two exceptions to this correlation were identified: low‐misorientation‐angle boundaries and the coherent twin boundary, where the (111) planes in the adjoining crystals are parallel to each other, but rotated by 60° around the [111] axis. In these cases, the high degree of coincidence across this interface probably lowers the boundary energy with respect to that of the component surfaces. For all other boundaries, the anisotropy of the population is accurately predicted by the surface energy anisotropy, and in general, boundaries display a preference for {100} orientations, the planes of minimum surface energy.

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Glutathione reductase (GR; EC 1.6.4.2) was purified from spinach roots (rGR) to homogeneity in terms of SDS‐PAGE, and its properties were compared with those of the enzyme from spinach leaves (IGR). The two enzymes had similar native molecular (118000) and subunit masses (58000) and immunochemical properties, but different pH optima (ca pH 7.8 for IGR, ca pH 7.2 for rGR) and amino acid compositions. Peptide maps of two GRs showed that they differed from each other. The N‐terminal amino acid of the IGR was glycine and that of the rGR was blocked. The partial amino acid sequence of the N‐terminal region of the IGR was determined to the 11 th residue and it was found that the sequence of 8 amino acids of the IGR had 100% homology with that of the putative chloroplast GR from Arabidopsis and pea.