Science. 1979 Oct 5;206(4414):20-3. doi: 10.1126/science.206.4414.20.
In the primitive angiosperms, closed carpels are believed to have evolved as protection for ovules, which would otherwise be injured by animal pollinators. The hypothesis is presented that, whatever the origin and other functions of angiosperms, insect pollination and closed carpels may, in combination, reduce the influence of random variation on pollen tube competition, thus enhancing the ability of natural selection to act on the gametophytic phase of the life cycle. The microgametophytic phase represented by vast numbers of haploid individuals can then serve, by insect pollination and closed carpels, as a screen against any genome not functioning with a high degree of metabolic vigor. Poorly balanced genomes could thus be eliminated at relatively little cost. Insect-pollinated angiosperms would therefore benefit from positive aspects of sexual recombination. Such a system may have allowed the angiosperms to undergo their rise to dominance.
在原始的被子植物中，封闭的心皮被认为是为保护胚珠而进化的，否则胚珠会被子植物的动物传粉者所伤害。本文提出了一个假说，无论被子植物的起源和其他功能如何，昆虫传粉和封闭的心皮可能会共同减少随机变异对花粉管竞争的影响，从而增强自然选择在配子体阶段发挥作用的能力。通过昆虫传粉和封闭的心皮，由大量单倍体个体代表的小配子体阶段可以作为一种屏障，防止任何基因组不能以高度代谢活力发挥作用。因此，不平衡的基因组可以以相对较小的代价被淘汰。传粉昆虫的被子植物因此可以受益于有性重组的积极方面。这样的系统可能使被子植物得以占主导地位。
