Bünning E, Moser I
Botanisches Institut der Universität Tübingen, Tübingen, Deutschland.
Planta. 1967 Jun;77(2):99-107. doi: 10.1007/BF00387447.
Shifting from DD (continuous darkness) to LL (continuous light; red with maximum at 660 nm) affects the circadian cycle of Phaseolus as follows. 1. The cycle which is directly influenced by this energy step (called the first cycle), is either shortened ("advance") or lengthened ("delay") as compared with the control cycle of about 28 hours (Fig. 1). The direction of this change, i.e., shortening or lengthening, is that which might be expected on the basis of the well known response curves. That means the influence of the single transition from DD to LL on this first cycle corresponds to the influence of light pulses in DD. 2. After light-pulses in DD, in Phaseolus as in the case of other species, a shortened first cycle will be followed by a shortened second one, a lengthened first cycle by a lengthened second one (see MOSER). After the step from DD to LL, however, a shortened first cycle is always followed by a lengthened second one (Fig. 2). A lengthened first cycle is followed either by a very short one (between about 10 and 18 hours), or by an extremely lengthened one (up to nearly 40 hours, Fig. 3). The curves reveal that the extremely short cycles are due to the initiation of a new oscillation superimposed on the preceding one which is still completing its last peak (Fig. 4). The frequency of new initiations depends on the height of the energy-step and on the phase of its occurrence (Fig. 3, 6). 3. The influence due to changing from LL to DD is rather slight (Fig. 5). 4. The experiments favor the assumption that circadian oscillations follow the model of certain biological oscillations with higher frequencies: apparently we are dealing with a chain of all-or-none reactions separated by refractory periods. Advances are due to a premature breaking of the refractory period. Their frequency thus depends on the height of the energy step and on the time elapsed after the preceding peak (Fig. 6). Delays mean an extension of the reaction due to higher energy supply, that is, they are due to a longer lasting "climbing" towards a higher peak than the preceding one (Fig. 4a).
从持续黑暗（DD）转变为持续光照（LL；660纳米处峰值的红光）对菜豆的昼夜节律周期有如下影响。1. 直接受此能量变化影响的周期（称为第一个周期），与约28小时的对照周期相比，要么缩短（“提前”），要么延长（“延迟”）（图1）。这种变化的方向，即缩短或延长，是基于众所周知的响应曲线所预期的。这意味着从DD到LL的单次转变对这个第一个周期的影响与DD中光脉冲的影响相对应。2. 在DD中给予光脉冲后，和其他物种一样，菜豆中第一个周期缩短后，第二个周期也会缩短；第一个周期延长后，第二个周期也会延长（见莫泽的研究）。然而，从DD转变到LL后，第一个周期缩短后，第二个周期总是延长（图2）。第一个周期延长后，要么接着一个非常短的周期（约10至18小时），要么接着一个极长的周期（长达近40小时，图3）。曲线显示，极短的周期是由于在仍在完成其最后一个峰值的前一个振荡上叠加了一个新的振荡（图4）。新振荡开始的频率取决于能量变化的幅度及其发生的相位（图3、6）。3. 从LL转变为DD的影响相当轻微（图5）。4. 这些实验支持这样一种假设，即昼夜节律振荡遵循某些频率更高的生物振荡模型：显然我们处理的是一系列由不应期分隔的全或无反应。提前是由于不应期过早结束。因此，它们的频率取决于能量变化的幅度以及前一个峰值之后经过的时间（图6）。延迟意味着由于更高的能量供应导致反应延长，也就是说，它们是由于比前一个峰值向更高峰值的持续“攀升”时间更长（图4a）。
