Diurnal change in temperature sensitivity gibba G3 induced by acetylcholine in continuous light

When Lemna gibba G3 was in contact with 10^–5 M Ach oreserine, floral response to chilling changed diurnally under24(0)], as was the case for control cultures exposed to 16(8)].On the other hand, with a rise in temperature, the min-24(0)]decreased discontinuously in 24-hr units in Ach cultures subjectedto 24(0)], as did the min-16(8)] in control cultures. Thusin the presence of Ach or eserine, this long-day plant tookthe continuous light regime, i.e. 24(0)], for another typeof long-day regime consisting of a long light period and a shortdark period, e.g. 16(8)]. In Ach cultures, the lower limitof the min-24(0)] (72 hr) was attained at 22.5?C and remainedunaltered at the higher temperatures examined. The min-16(8)]for control cultures, however, known to reach its lower limit(48 hr) at 26?C. Sodium lauryl sulphate (10^–5 M) and ouabain(10^–6 M) also caused a similar diurnal change in temperaturesensitivity of 24(0)] cultures. We surmised that exogenous Ach or inserted dark period modifiesthe relative rates chemical and physical component reactionsinvolved in the floral evocation processes, resulting in therhythmical floral response to chilling. (Received August 1, 1974; )