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Cellular Responses to Thermal and Photo Stress I. Euglena and Chlamydomonas *
Author(s) -
GROSS J. A.,
JAHN T. L.
Publication year - 1962
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1962.tb02631.x
Subject(s) - euglena , chlamydomonas , chloroplast , biophysics , botany , euglena gracilis , biology , chemistry , biochemistry , gene , mutant
SYNOPSIS.Euglena and Chlamydomonas were cultured in an organic medium in the dark and at several light intensities (15, 60 and 150 ft‐c) at temperatures from 20d̀ to 35d̀C. Below 32.5d̀, growth of Euglena was independent of light. Chlamydomonas was light dependent at all temperatures where growth occurred; there was no growth in the dark, at 15 ft‐c, or at temperatures above 32.5d̀. At 35d̀, growth of Euglena became inversely light dependent; the higher the illumination, the poorer the growth. Multinucleated, giant euglenas were found at 35d̀, a greater percent of abnormal cells appearing at the higher light intensities. Monsters were not observed in Chlamydomonas. To explain the growth‐inhibiting, monster‐inducing effect of elevated temperatures on Euglena , it is postulated that a dark‐formed thermosensitive protein, essential for normal cell division, is denatured. Light may increase the effect of heat on chlorophyll and the chloroplast, possibly by being converted to intraplastidic heat through the plastid carotenoids, thus having some indirect synergistic role in the phenomenon.