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ULTRASTRUCTURE OF TALL FESCUE ( FESTUCA ARUNDINACEA SCHREB. CV. S170) CELLS FIXED WHILE EXPOSED TO LETHAL OR NON‐LETHAL EXTRACELLULAR FREEZING
Author(s) -
PEARCE R. S.
Publication year - 1982
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1982.tb03384.x
Subject(s) - festuca arundinacea , extracellular , ultrastructure , biology , chloroplast , meristem , membrane , cytoplasm , thylakoid , intracellular , microbiology and biotechnology , botany , anatomy , biophysics , biochemistry , poaceae , shoot , gene
SUMMARY A freeze‐substitution method was used to fix tissues (from roots, leaf laminae and leaf meristem of tall fescue) subjected to lethal or non‐lethal extracellular freezing, which induced intracellular dehydration. There was no evidence of direct (tearing) damage by extracellular ice. In the tissues fixed while so frozen, the cytoplasm was coherent and the plasmalemma was present but the trilamellar structure of membranes was not always evident, e.g. it was usual in thylakoid membranes but was rare in the peripheral membranes of chloroplasts. An abnormal feature was the presence of strongly osmiophilic material, often associated with membranous structures and possibly of more than one type. The appearance of the frozen tissues and the amount of strongly osmiophilic material did not vary with hardiness. When a lethal freezing treatment was given, strongly osmiophilic material occurred at the same sites in both frozen and thawed tissues, but it was largely absent from thawed non‐lethally frozen tissues, though present in the same material before thawing. The occurrence of intact plasmalemmata in tissues fixed while lethally frozen and of strongly osmiophilic material in tissues fixed while non‐lethally frozen, are in contrast to some other recent work.