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A MORPHOMETRIC ANALYSIS OF CYTOLOGICAL CHANGES DURING SPORE MATURATION IN THE MYXOMYCETE DIDYMIUM IRIDIS
Author(s) -
Fagerberg W. R.,
Mims C. W.
Publication year - 1985
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1985.tb05361.x
Subject(s) - spore , biology , organelle , vacuole , ultrastructure , volume (thermodynamics) , botany , microbiology and biotechnology , cytoplasm , physics , quantum mechanics
Ultrastructure of spore maturation in the myxomycete Didymium iridis was investigated using morphometric analytical techniques. Changes in actual volume (μm 3 ) and relative volume (Vv) of nuclei, autophagic vacuoles, mitochondria, microbodies, lipid droplets, and spore wall were described for spores in three stages of development. Stage I spores were newly formed, surrounded only by the cell membrane. Stage II spores were approximately 1 hr older than Stage I spores and possessed surface spines, but little if any additional wall material. Stage III spores were 24 hr old and possessed a fully formed, multilayered wall. The results of this study indicate that spore maturation in D. iridis is a multistep process involving a decrease in spore volume and coordinated changes in specific organelle compartments. From Stage I to Stage III, mean spore volume decreased by more than 50%. Percent volume data (Vv) showed that Stage I spores allocated volume equally to all measured organelles except microbodies and the spore wall, the latter of which had not yet begun to develop. By Stage II, only the nucleus and spore wall showed significant changes in Vv values, both increasing. In terms of actual volume, the nucleus, autophagic vacuole and spore wall increased by Stage II. Between Stages II and III the cell wall was the only component to increase in volume, all others decreased in volume. Our data indicate a close relationship between a decrease in organelle volume and an increase in cell wall volume in the Stage III spore. The autophagic vacuole and the cell wall dominated the volume of the Stage III spore while the remaining volume was allocated unequally to the other components.