Photoperiodic induction of pupal diapause in the flesh fly,Sarcophaga crassipalpis: embryonic sensitivity
Photoperiodic induction of pupal diapause in the flesh fly,Sarcophaga crassipalpis: embryonic sensitivity
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肉蝇蛹滞育的光周期诱导，石蝇：胚胎敏感性
DOI：
10.1007/bf00683221
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
D. Denlinger
中科院分区：
文献类型：
--
作者：
A. Gnagey;D. Denlinger
胚胎发育的最后两天对肉蝇Sarcophaga crassipalpis的蛹滞育至关重要。短日照（大于10 1/2小时的黑暗）在此期间允许滞育的表达，而长日照在此短暂的敏感阶段消除滞育的潜力。虽然需要三小时的光照来分隔连续的黑暗期，但暗相的长度而不是暗相的长度决定了滞育的程序。在暗相早期，光敏性仅限于蓝光（小于540 nm）。根据光中断对滞育表达的影响，暗期可分为4个阶段。在第一阶段（0-6小时后，暗期发病）胚胎是高度敏感的光中断和滞育被有效地消除。一段时间的不敏感的光，第二阶段，从6小时后开始的暗期。10- 11小时的光中断与临界暗相长度一致，导致滞育的部分减少。在第四阶段，暗相反应完成，滞育能力即使在光的存在下也被保留。虽然光中断导致在整个阶段I滞育的消除，从1小时光中断的恢复时间（黑暗的长度需要对抗光中断的影响）显着不同，取决于光中断时提出。在第一阶段的早期（0- 3小时），光中断的恢复是迅速的，而在第一阶段的晚期（4- 6小时），光的影响是不容易逆转的。因此，暗相反应似乎遵循逐步进展，而不是代表简单的线性反应。我们提出了一个分子模型，可以解释的暗相反应的动力学。
The last two days of embryonic development are crucial in programming pupal diapause in the flesh fly,Sarcophaga crassipalpis. Short daylength (greater than 10 1/2h of darkness) during this interval permits expression of diapause while long daylength during this brief sensitive stage eliminates the potential for diapause. Length of scotophase rather than photophase programs the diapause although three hours of light is needed to separate tandem dark periods. Early in the scotophase, photosensitivity is restricted to blue light (less than 540 nm). The scotophase can be divided into 4 phases according to the effect of light breaks on diapause expression. During Phase I (0–6 h after scotophase onset) embryos are highly sensitive to light interruption and diapause is effectively eliminated. A period of insensitivity to light, Phase II, extends from 6–hh after onset of scotophase. Light breaks at 10–11h coincide with the critical scotophase length and result in a partial reduction of diapause. In Phase IV, the scotophase reaction is complete and diapause competence is preserved even in the presence of light. Although light breaks result in elimination of diapause throughout Phase I, recovery time from a 1 h light break (length of darkness needed to counter the effect of a light break) differs dramatically depending upon when the light break is presented. Early in Phase I (0–3h) recovery from light interruption is rapid, while late in Phase I (4–6h), the effects of light are not readily reversible. The scotophase reaction thus appears to follow a step-wise progression rather than represent a simple linear response. We present a molecular model that could account for the dynamics of the scotophase reaction.