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Biomedical subjects

R M Klein

Publications and source records attributed to R M Klein.

At least 199 records · Page 11Linked to original sources
PubMed1972

Phytochrome control of growth cessation and initiation of cold acclimation in selected woody plants.

Short day enhancement of cold acclimation in twigs of Cornus (red-osier dogwood), Weigela, and Pyracantha (firethorn) was studied using dark interruptions with red or with red-far red radiation. Hardiness was estimated by freezing stem tissues to preselected temperatures and evaluating injury electrolytically. Dark-period interruptions with red radiation suppressed cold acclimation in Cornus and Weigela. When red light was followed by far red light, suppression was relieved. No radiation control of acclimation was found with Pyracantha. The short day enhancement of cold acclimation in Cornus and Weigela appears to be phytochrome-mediated.

Journal Article↗
PubMed1966

Substitution of redox chemicals for radiation in phytochrome-mediated photomorphogenesis.

The reducing agents, potassium ferrocyanide, beta-mercaptoethylamine, cysteine, reduced DPN, ferrous sulfate, methyl viologen and ascorbic acid caused the expansion in darkness of disks of primary leaf tissue cut from dark-grown bean plants. The reducing agents interacted synergistically with low irradiances of red radiation and additively with high irradiance of red light. Exposure of disks treated with reducing agents to far red light repressed disk expansion and the decay in sensitivity to far red radiation showed the same time relations as sequential exposure to red and far red radiation.The oxidizing agents, 1,4-naphthoquinone, ferric sulfate, hydrogen peroxide, t-butyl hydroperoxide, cystine, and potassium ferricyanide repressed the expansion of leaf disks initiated by exposure to red radiation. The oxidizing agents interacted synergistically with low irradiances of far red light and additively with irradiances of far red light.

Journal Article↗