Cryptic self-incompatibility and distyly in Hedyotis acutangula Champ. (Rubiaceae).
Cryptic self-incompatibility and distyly in Hedyotis acutangula Champ. (Rubiaceae).
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DOI：
10.1111/j.1438-8677.2009.00242.x
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发表时间：
2010-05
期刊：
影响因子：
3.9
通讯作者：
X. Wu;A. Li;D. Zhang
中科院分区：
文献类型：
--
作者：
X. Wu;A. Li;D. Zhang
花的二型性是茜草科重要的有性系统，通常与两性异形、自交不亲和、花内不亲和和次生二型性有关。在这里，我们报告了一种不寻常的distyly与自我和/或intramorph兼容性的多年生草本植物，尖叶耳草。对两种变型的花部形态、辅助二型性和相容性进行了研究。H. Acutangula没有表现出精确的相互herkogamy，但这并不影响平等的花型在人口中，通常发现在distylous植物。针、穗花粉在8h内仍保持较高的生活力。针式花的花粉与胚珠之比为72.5，线式花的花粉与胚珠之比为54.4。针形花的雌蕊比线形花的雌蕊保持更长的可接受性。在离体培养中，针形和线形花粉的萌发率没有明显差异，但线形花粉管的生长速度明显快于针形花粉管。人工授粉表明，在合法的异形体杂交的花粉管生长速度比无论是在异形体杂交或自花授粉，这表明在这个物种的发生的隐性自交不亲和。隐性自交不亲和性在两种形态中的作用不同，在针形花中，合法和非法授粉后的花粉管生长速率比在线形花中分化得更高。在去雄的网状花中没有产生果实，表明没有无融合生殖。结果表明，H. Acutangula是二型的，具有隐蔽的自交不亲和育种系统。
Distyly, floral polymorphism frequently associated with reciprocal herkogamy, self- and intramorph incompatibility and secondary dimorphism, constitutes an important sexual system in the Rubiaceae. Here we report an unusual kind of distyly associated with self- and/or intramorph compatibility in a perennial herb, Hedyotis acutangula. Floral morphology, ancillary dimorphisms and compatibility of the two morphs were studied. H. acutangula did not exhibit precise reciprocal herkogamy, but this did not affect the equality of floral morphs in the population, as usually found in distylous plants. Both pin and thrum pollen retained relatively high viability for 8 h. The pollen to ovule ratio was 72.5 in pin flowers and 54.4 in thrum flowers. Pistils of pin flowers remained receptive for longer than those of thrum flowers. No apparent difference in the germination rate of pin and thrum pollen grains was observed when cultured in vitro, although growth of thrum pollen tubes was much faster than that of pin pollen tubes. Artificial pollination revealed that pollen tube growth in legitimate intermorph crosses was faster than in either intramorph crosses or self-pollination, suggesting the occurrence of cryptic self-incompatibility in this species. Cryptic self-incompatibility functioned differently in the two morphs, with pollen tube growth rates after legitimate and illegitimate pollination much more highly differentiated in pin flowers than in thrum flowers. No fruit was produced in emasculated netted flowers, suggesting the absence of apomixis. Our results indicate that H. acutangula is distylous, with a cryptic self-incompatibility breeding system.