Instituto de Biologia, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil.
Plant Biol (Stuttg). 2013 Sep;15(5):919-24. doi: 10.1111/j.1438-8677.2012.00692.x. Epub 2012 Nov 5.
Self-compatibility in apomictic pseudogamic species is considered fundamental to assure reproduction by seeds in extreme situations, making apomictic species more advantageous than sexual ones in these scenarios. Anemopaegma acutifolium is a polyploidy, apomictic sporophytic species with no endosperm development in ovules of unpollinated pistils, which indicates obligate pseudogamy. Thus, the aim of the present work is to study the breeding system and post-pollination events to test if there is similar pseudogamous development irrespective of pollination treatment. We analysed fruit and seed set obtained in controlled experimental pollinations, as well as embryo number per seed, and the progress of ovule penetration, fertilisation and early endosperm development between self- and cross-pollinated pistils. We found that the species is self-fertile and that spontaneous selfing fruit set is also possible, although emasculated flowers never form fruits. Selfed pistils were as efficient as crossed ones for all parameters analysed, except for a delay in endosperm development observed in the former that may be an effect of the late-acting self-incompatibility. Therefore, the avoidance of selfed pistil abortion seems to be promoted by the presence of adventitious embryos and a normal endosperm. We conclude that A. acutifolium shows apomixis-related pseudo-self-compatibility, as in other self-fertile apomictic species of Bignoniaceae, which confer reproductive assurance and increases fruit-set and persistence ability in fast-changing tropical habitats.
无融合生殖假结合种的自交亲和性被认为是在极端情况下通过种子繁殖的基础，这使得无融合生殖种在这些情况下比有性种更具优势。扁担藤是一种多倍体无融合生殖的孢子体物种，在未授粉的雌蕊胚珠中没有胚乳发育，这表明其为强制性假结合。因此，本研究旨在研究其繁殖系统和授粉后事件，以检验是否存在类似的假结合发育，而不论授粉处理如何。我们分析了控制授粉实验中获得的果实和种子结实率，以及每个种子的胚胎数量，以及自交和杂交授粉雌蕊中胚珠穿透、受精和早期胚乳发育的进展。结果表明，该物种是自交可育的，即使进行了去雄处理，也可以自发进行自交结实，尽管去雄的花朵从未形成果实。自交雌蕊在所有分析参数上与杂交雌蕊一样有效，除了前者胚乳发育延迟，这可能是迟发性自交不亲和的影响。因此，避免自交雌蕊败育似乎是由不定胚和正常胚乳的存在所促进的。我们得出结论，扁担藤表现出与无融合生殖相关的假自交亲和性，就像在其他自交可育的大戟科无融合生殖种中一样，这赋予了繁殖保障，并增加了在快速变化的热带栖息地中的果实结实率和持久性。
