Floral development and the formation of unisexual spikelets in the Andropogoneae (Poaceae).
Floral development and the formation of unisexual spikelets in the Andropogoneae (Poaceae).
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DOI：
10.2307/2656757
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发表时间：
1999-03
影响因子：
3
通讯作者：
Lucia G. Le Roux;Elizabeth A. Kellogg
中科院分区：
文献类型：
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作者：
Lucia G. Le Roux;Elizabeth A. Kellogg
我们调查了小穗发育在四个远相关的物种的草族Andropogoneae，以确定是否小穗发育和单性小花的形成是均匀的整个部落。我们研究了发展的白羊草bladhii，Coelorachis aurita，Heteropogon contortus，和Hyparaproxia hirta，并比较这些与Panicum，一个成员的姐妹部落Paniceae。我们所研究的物种中小穗发育的许多方面与已经知道的Tripsacum和玉米（Andropogoneae）相关，尽管单性小花在植物上的分布方式存在差异。单性小穗的形成也是均匀的。所有的小花都同时发生雌蕊和雄蕊原基。在注定是雄性的小花中，在雌蕊群脊形成之后，雌蕊群的亚表皮层中发生细胞死亡。在注定是雌性的小花中，雄蕊中没有明显的细胞死亡，但花药形成后生长停止。在小穗发育和单性小花的形成的相似性点的性别决定在整个Andropogoneae和可能的整个Panicoideae的一个共同的遗传机制。利用细胞死亡途径导致雌蕊群败育可能是定义该亚科的一个形态学特征的基础。
We investigated spikelet development in four distantly related species of the grass tribe Andropogoneae to determine whether spikelet development and the formation of unisexual florets are uniform throughout the tribe. We studied development in Bothriochloa bladhii, Coelorachis aurita, Heteropogon contortus, and Hyparrhenia hirta, and compared these with Panicum, a member of the sister tribe Paniceae. Many aspects of spikelet development in the species we have studied correlate with what is already known for Tripsacum and maize (both Andropogoneae), despite variation in how unisexual florets are distributed on the plant. The formation of unisexual spikelets is also uniform. All florets initiate both pistil and stamen primordia. In florets destined to be male, cell death occurs in the subepidermal layers of the gynoecium after the formation of a gynoecial ridge. In florets destined to be female, there is no apparent cell death in the stamens, but growth ceases after anther formation. The similarity in spikelet development and the formation of unisexual florets point to a common genetic mechanism for sex determination throughout the Andropogoneae and possibly the entire Panicoideae. Use of a cell death pathway to cause gynoecial abortion may be the basis of one morphological character that defines the subfamily.