An endogenous rhythm in the rate of carbon dioxide output of Bryophyllum - III. The effects of temperature changes on the phase and period of the rhythm

作者：M. B. Wilkins · 发表于：Proceedings of the Royal Society B Biological Sciences · 年份：1962 · DOI：10.1098/rspb.1962.0041 · 被引用次数：45 · 研究领域：Biocrusts and Microbial Ecology、Slime Mold and Myxomycetes Research、Lichen and fungal ecology

Abstract 1. Excised leaves of Bryophyllum fedtschenkoi show an endogenous rhythm in their rate of carbon dioxide output when they are kept in darkness and at a constant temperature. The effects of various constant ambient temperatures and of changes in temperature on the phase and period of this rhythm have been investigated. 2. Both the phase and period of a rhythm initiated by transferring leaves from light to darkness are determined by the constant ambient temperature between 16 and 31°C. The time between the onset of darkness and the first peak of the rhythm (the transient, Tt) deter­mines the phase. This time is 16.8 ± 0.3 h at 31°C and 24.7 ± 0.3 h at 16°C. The period reaches a steady value after the first peak of the rhythm and is temperature compensated to a greater extent than the transient. It is 20.8 + 0.4 h at 31°C and 23.9 + 0.2 h at 16°C. The ratio of (period at 16°C)/(period at 26°C) is 1.06 whereas, that of (transient at 16 °C)/(transient at 26°C) is 1.30. 3. The rhythm is inhibited in leaves held at 36°C but begins again when the temperature is reduced to 26 or 16 °C. The first peaks occur 18 to 19 h and 24 to 25 h respectively after the change to the lower temperature. These times are similar to those between the end of an inhibitory light treatment and the first peak of the rhythm in leaves held at 26 and 16°C. 4. When leaves kept in darkness at either 26 or 16°C are exposed to 36°C for several hours it is found that: (a) the phase of the rhythm is reset by...