Am J Bot. 1997 May;84(5):626.
This study explores whether ecological factors, such as pollinators and pollen flow, or variation in pollen and ovule development account for the observed differences (approximately twofold) in the reproductive output of pin and thrum individuals of Erythroxylum havanense. The importance of ecological factors was assessed by means of comparison of the identity of pollinators and the rates of flower visitation, and by performing controlled hand pollinations and measurements of fruit set. In addition, we described the pollen and ovule development of thrum and pin individuals. Our results indicate that pollinators of E. havanense do not distinguish between floral morphs. The differences in fruit set between pin and thrum plants held even after hand pollination and, therefore, the observed differences in reproductive output between floral morphs of E. havanense cannot be explained in terms of asymmetrical pollen flow. There were no differences in the pattern of gynoecium development between the pin and thrum morphs, however androecium development showed marked differences between the morphs, and there was a resemblance between the developmental pathways leading to male sterility of the thrum morph of E. havanense with that of species with cytoplasmic male sterility (CMS).
本研究探讨了生态因素，如传粉者和花粉流，或花粉和胚珠发育的变化是否解释了 Erythroxylum havanense 中针状和管状个体生殖输出的观察到的差异（约两倍）。通过比较传粉者的身份和花朵访问率，并进行控制的人工授粉和果实结实率测量，评估了生态因素的重要性。此外，我们还描述了管状和针状个体的花粉和胚珠发育。我们的结果表明，E. havanense 的传粉者不会区分花形态。即使在人工授粉后，针状和管状植株之间的果实结实率差异仍然存在，因此，E. havanense 花形态之间观察到的生殖输出差异不能用不对称花粉流来解释。针状和管状形态之间的雌蕊发育模式没有差异，但是雄蕊发育形态之间存在明显差异，并且 E. havanense 管状形态雄性不育的发育途径与细胞质雄性不育（CMS）物种的雄性不育的发育途径相似。
