Department of Plant Biology, Cornell University, Ithaca, New York 14853 USA.
Am J Bot. 2009 Jan;96(1):366-81. doi: 10.3732/ajb.0800126. Epub 2008 Dec 19.
The rapid diversification and ecological dominance of the flowering plants beg the question "Why are there so many angiosperm species and why are they so successful?" A number of equally plausible hypotheses have been advanced in response to this question, among which the most widely accepted highlights the mutually beneficial animal-plant relationships that are nowhere better developed nor more widespread than among angiosperm species and their biotic vectors for pollination and dispersal. Nevertheless, consensus acknowledges that there are many other attributes unique to or characteristic of the flowering plants. In addition, the remarkable coevolution of the angiosperms and pollination/dispersal animal agents could be an effect of the intrinsic adaptability of the flowering plants rather than a primary cause of their success, suggesting that the search for underlying causes should focus on an exploration of the genetic and epigenetic mechanisms that might facilitate adaptive evolution and speciation. Here, we explore angiosperm diversity promoting attributes in their general form and draw particular attention to those that, either individually or collectively, have been shown empirically to favor high speciation rates, low extinction rates, or broad ecological tolerances. Among these are the annual growth form, homeotic gene effects, asexual/sexual reproduction, a propensity for hybrid polyploidy, and apparent "resistance" to extinction. Our survey of the literature suggests that no single vegetative, reproductive, or ecological feature taken in isolation can account for the evolutionary success of the angiosperms. Rather, we believe that the answer to Darwin's second "abominable mystery" lies in a confluence of features that collectively make the angiosperms unique among the land plants.
“为什么有这么多种被子植物，它们为什么如此成功？”针对这个问题，提出了许多同样合理的假设，其中最广泛接受的假设强调了动植物之间互利的关系，这种关系在被子植物及其生物传粉和传播媒介中得到了 nowhere better developed nor more widespread 的发展和传播。然而，共识承认，开花植物还有许多其他独特的属性。此外，被子植物与传粉/传播动物媒介的显著共同进化可能是开花植物内在适应性的结果，而不是它们成功的主要原因，这表明寻找根本原因应该集中在探索可能促进适应性进化和物种形成的遗传和表观遗传机制上。在这里，我们以一般形式探讨了促进被子植物多样性的属性，并特别关注那些单独或集体地被经验证明有利于高物种形成率、低灭绝率或广泛生态耐受性的属性。其中包括一年生生长形式、同源基因效应、无性/有性繁殖、杂种多倍体的倾向以及明显的“抗灭绝”能力。我们对文献的调查表明，没有任何单一的营养、生殖或生态特征可以单独解释被子植物的进化成功。相反，我们认为，达尔文第二个“可恶的谜团”的答案在于一系列特征的融合，这些特征使被子植物在陆地植物中独树一帜。
