背景回顾：Biological rhythms are ubiquitous. They can be generated by circadian oscillators, which produce daily rhythms in physiology and behavior, as well as by developmental oscillators such as the segmentation clock, which produces modular developmental units in a periodic fashion. 

主要发现：Here, we show that the circadian clock controls the timing of late-stage floret development, or anthesis, in domesticated sunflower. 

结果1-向日葵花发育模式：In these plants, what appears to be a single inflorescence consists of up to thousands of individual florets tightly packed onto a capitulum disk. While early floret development occurs continuously across capitula to generate iconic spiral phyllotaxy, during anthesis floret development occurs in discrete ring-like pseudowhorls with up to hundreds of florets undergoing simultaneous maturation. 

结果2-生物钟介导的花发育调控：We demonstrate circadian regulation of floral organ growth and show that the effects of light on this process are time-of-day dependent. Disruption of circadian rhythms in floral organ development causes loss of pseudowhorl formation. 

结论：Thus, we show that the sunflower circadian clock acts in concert with environmental response pathways to tightly synchronize the anthesis of hundreds of florets each day, generating spatial patterns on the developing capitulum disk. 

意义：This coordinated mass release of floral rewards at predictable times of day likely promotes pollinator visits and plant reproductive success.

Developmental patternsobserved when sunflowers undergoanthesis in different environmental conditions.

Speculative modelfor transition of floret developmentfrom age-dependent continuous gradients to organization into discrete pseudowhorls that undergocoordinated anthesis.

生物节律无处不在。其可以由生物钟振荡器产生，在生理和行为上产生日节律，也可以发育振荡器产生，如以周期性方式产生模块化发育单元等分段时钟。本文中，作者发现在驯化的向日葵中，生物钟控制着晚期小花发育的时间或者开花的时间。在这些植物中，看上去似乎是一个单一的花序，但其实是由多达数千个紧密地排列的小花组成的头状花序。虽然小花的早期发育在头状体上持续发生，以产生标志性的螺旋叶序，但在开花期间，小花的发育发生在离散的环状拟轮生体中，多达数百朵小花同时成熟。作者证明了花器官生长的生物钟调节，并发现光照对这一过程的影响依赖于当日时段。花器官发育过程中生物节律的扰乱，导致了拟轮生形成的缺失。因此，作者提出向日葵的生物钟与环境响应途径协同作用，从而保证每天数百朵小花的同步开花，在发育中的头状花序中产生空间模式。这种在一天中可预测的时间协调大量花朵的同步开放可能会促进授粉者的访问和植物的生殖成功。

This paper, of relevance to a broad range of plant biologists and colleagues in the circandian field, reports important results that demonstrate circadian coordination of characteristic floral development in sunflower. The current manuscript includes convincing observations and possible hypotheses, but the ecological relevance of the temporally-controlled flower development is incompletely shown.

本文的研究属于植物生物学中涉及生物钟领域方向，报道了向日葵中生物钟协调花发育时空模式的重要结果。目前的手稿包括令人信服的试验观察以及可能的假设，但是有关花发育的时间控制在生态上的意义仍不完备。

p.s. eLife近期宣布引入新的论文发表模式，即经过同行评议的论文不在选择‘拒稿/接收’，而是直接发布，同时附上eLife的评估（assessment）以及公众评论。作者也可以发表对审稿人或者eLife assessment的回应。而后，作者可以选择修改和重新提交，也可以选择不修改，直接为最后的版本记录（final Version of Record）。

p.s. 论文后面同时附上了三位审稿人的评议，有兴趣的可以查看原文。

** Stacey L. Harmer **