Morphology and Development of Calcium Oxalate Deposits in Gilbertella Persicaria (Mucorales)

Walls of sporangiophores and sporangia of Gilbertella persicaria contain conspicuous deposits of calcium oxalate. The morphology of these crystalline deposits varies with location on the fruiting structure. Deposits over most of the sporangiophore consist of elongate, flattened plates embedded in the sporangiophore wall, and these plates often bear single or paired, upright appendages. In the area of transition between sporangiophore and sporangium the crystals consist of short, verrucose projections borne on flattened, polygonal basal plates. Crystals on the sporangium proper are morphologically complex, composed of an apical, flattened, polygonal cap, an angular, upright column, and a flattened, polygonal base plate. Scanning electron micrographs and X-ray elemental analysis of these crystals are presented. The morphology of these crystals and their relationship to sporangiophore and sporangium development are discussed, along with speculations on the function of these deposits.