Summary
The ultrastructural changes occurring in cotyledon protein bodies of germinating squash seeds were investigated using mainly the freeze-etching technique. The appearance and subsequent disappearance of soft globoid-like material in the proteinaceous matrix was documented as the first major ultrastructural change. The globoid crystal was digested either by the formation of internal pitted regions or through external digestion. During later stages of breakdown the protein bodies became a series of largely aqueous vacuoles containing irregularly shaped pieces of protein material. This protein material eventually disappeared and the vacuoles fused to form the central vacuole of the mesophyll cells. This fusion of vacuoles was followed in living cells using Nomarski optics.
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This research was supported by grants from the National Research Council of Canada. The authors gratefully acknowledge the technical assistance of Mr. J.Darley, Mr. P.Larsen, and Miss C.Turner. The criticisms of the manuscript provided by Dr. L.Peterson were most helpful.
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Lott, J.N.A., Vollmer, C.M. Changes in the cotyledons ofCucurbita maxima during germination. Protoplasma 78, 255–271 (1973). https://doi.org/10.1007/BF01275695
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DOI: https://doi.org/10.1007/BF01275695