Department of Biology, University of Padua, Padua, Italy.
Mol Biol Evol. 2012 Jan;29(1):409-19. doi: 10.1093/molbev/msr244. Epub 2011 Oct 4.
Botanical fruits derive from ovaries and their most important function is to favor seed dispersal. Fleshy fruits do so by attracting frugivorous animals that disperse seeds together with their own excrements (endozoochory). Gymnosperms make seeds but have no ovaries to be transformed into fruits. Many species surround their seeds with fleshy structures and use endozoochory to disperse them. Such structures are functionally fruits and can derive from different anatomical parts. Ginkgo biloba and Taxus baccata fruit-like structures differ in their anatomical origin since the outer seed integument becomes fleshy in Ginkgo, whereas in Taxus, the fleshy aril is formed de novo. The ripening characteristics are different, with Ginkgo more rudimentary and Taxus more similar to angiosperm fruits. MADS-box genes are known to be necessary for the formation of flowers and fruits in Angiosperms but also for making both male and female reproductive structures in Gymnosperms. Here, a series of different MADS-box genes have been shown for the first time to be involved also in the formation of gymnosperm fruit-like structures. Apparently, the same gene types have been recruited in phylogenetically distant species to make fleshy structures that also have different anatomical origins. This finding indicates that the main molecular networks operating in the development of fleshy fruits have independently appeared in distantly related Gymnosperm taxa. Hence, the appearance of the seed habit and the accompanying necessity of seed dispersal has led to the invention of the fruit habit that thus seems to have appeared independently of the presence of flowers.
植物果实来源于子房，其最重要的功能是促进种子传播。肉质果实通过吸引食果动物，将种子与其自身的排泄物一起传播（内动物传播）。裸子植物产生种子，但没有子房转化为果实。许多物种用肉质结构包围种子，并利用内动物传播来传播它们。这些结构在功能上是果实，可以来源于不同的解剖部位。银杏和红豆杉的果实状结构在解剖学起源上有所不同，因为银杏的外种皮肉质化，而红豆杉的肉质假种皮是新形成的。成熟特征也不同，银杏更为原始，而红豆杉更类似于被子植物的果实。众所周知，MADS 框基因对于被子植物花和果实的形成是必要的，但对于裸子植物雌雄生殖结构的形成也是必要的。在这里，一系列不同的 MADS 框基因首次被证明也参与了裸子植物果实状结构的形成。显然，相同的基因类型在系统发育上相距较远的物种中被招募，以形成具有不同解剖学起源的肉质结构。这一发现表明，在肉质果实发育中起主要作用的分子网络在亲缘关系较远的裸子植物分类群中独立出现。因此，种子习性的出现以及随之而来的种子传播的必要性导致了果实习性的出现，而果实习性似乎独立于花的存在而出现。
