Salk Institute for Biological Studies, Plant Biology Laboratory, La Jolla, CA, 92037, USA.
Howard Hughes Medical Institute Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
Plant Cell Environ. 2017 Nov;40(11):2487-2501. doi: 10.1111/pce.12900. Epub 2017 Feb 23.
Daily cycles of light and dark provide an organizing principle and temporal constraints under which life on Earth evolved. While light is often the focus of plant studies, it is only half the story. Plants continuously adjust to their surroundings, taking both dawn and dusk as cues to organize their growth, development and metabolism to appropriate times of day. In this review, we examine the effects of darkness on plant physiology and growth. We describe the similarities and differences between seedlings grown in the dark versus those grown in light-dark cycles, and the evolution of etiolated growth. We discuss the integration of the circadian clock into other processes, looking carefully at the points of contact between clock genes and growth-promoting gene-regulatory networks in temporal gating of growth. We also examine daily starch accumulation and degradation, and the possible contribution of dark-specific metabolic controls in regulating energy and growth. Examining these studies together reveals a complex and continuous balancing act, with many signals, dark included, contributing information and guiding the plant through its life cycle. The extraordinary interconnection between light and dark is manifest during cycles of day and night and during seedling emergence above versus below the soil surface.
昼夜循环为地球上的生命进化提供了组织原则和时间约束。虽然光通常是植物研究的焦点，但它只是故事的一半。植物不断地适应周围环境，将黎明和黄昏作为线索，将其生长、发育和代谢组织到一天中的适当时间。在这篇综述中，我们研究了黑暗对植物生理学和生长的影响。我们描述了在黑暗中生长的幼苗与在明暗循环中生长的幼苗之间的异同，以及黄化生长的进化。我们讨论了生物钟如何与其他过程整合，仔细研究了时钟基因与促进生长的基因调控网络在生长的时间门控中的接触点。我们还研究了每日淀粉的积累和降解，以及暗期特异性代谢控制在调节能量和生长方面的可能贡献。综合研究这些结果揭示了一个复杂而连续的平衡行为，许多信号（包括黑暗）提供信息并引导植物完成其生命周期。在白天和黑夜的循环以及种子在土壤表面上方和下方的萌发过程中，光和暗之间的非凡联系表现得尤为明显。
