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GERMINATION OF THE LIGHT‐SENSITIVE SEEDS OF CUCUMIS ANGUR1A AND RUMEX OBTUSIFOLIUS : EFFECTS OF TEMPERATURE
Author(s) -
Felippe G. M.
Publication year - 1980
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.1469-8137.1980.tb04551.x
Subject(s) - cucumis , darkness , germination , rumex , biology , botany , far red , red light , white (mutation) , white light , horticulture , physics , biochemistry , gene , optics
S ummary The effect of temperature and exposure to far red light were compared using positively photoblastic seeds of Cucumis and negatively photoblastic seeds of Rumex . Short exposure of Cucumis seeds to 45°C was without effect but exposure at 0°C for 1 to 3 h promoted subsequent germination in white light at a constant temperature of 25°C. In contrast, white light alternating temperatures 25/10 and 25/5°C fully counteracted the inhibitory effect of light on germination of Cucumis seeds. The temperature pairs 15/35, 20/35, and 25/35°C were tested with both Rumex (in darkness) and Cucumis (in light). Seeds of both species had their germination strongly promoted by the 15/35°C pair. The pair 25/35°C had a promotive effect in Rumex and no effect in Cucumis , while the pair 20/35°C was very effective for Rumex but much less so for Cucumis . In experiments in which the alternating pair 25/5°C was combined with far red (followed by darkness and white light), Rumex and Cucumis seeds behaved similarly. With both, when far red was given during the 5°C period followed by light or darkness at 25°C germination was promoted (but the inhibitory effect was completely reversed only where far red was followed by white light). When far red was given at 25°C followed by white light or darkness during the 5°C period germination was not promoted. Thus, both positively and negatively photoblastic seeds show the same behaviour in relation to light and temperature when exposed to far red.