Comparative pollen morphology in the early‐divergent angiosperm family Hydatellaceae reveals variation at the infraspecific level
Comparative pollen morphology in the early‐divergent angiosperm family Hydatellaceae reveals variation at the infraspecific level
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DOI：
10.1080/00173130802184214
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发表时间：
2008-06
期刊：
影响因子：
0.9
通讯作者：
M. Remizowa;D. Sokoloff;T. Macfarlane;S. Yadav;C. Prychid;P. Rudall
中科院分区：
文献类型：
--
作者：
M. Remizowa;D. Sokoloff;T. Macfarlane;S. Yadav;C. Prychid;P. Rudall
小水生家庭Hydatellaceae最近被分配到早期分歧被子植物订单Nymphaeales。用扫描电镜和光镜观察了海枣科12种植物的花粉形态，用透射电镜观察了一种植物的花粉形态。潜水a）。这些意见进行了比较，花粉数据从其他两个家庭的睡莲目，睡莲科和Cabombaceae，包括原来的意见，两个属的Cabombaceae。海枣科的花粉形态种间差异不显著，但多年生种（不显三柱藻和三柱藻）的花粉形态种间差异不显著。filamentosa）可能是无融合生殖的，至少具有部分不育和塌陷的花粉。花粉小，长圆形或圆形（从远极观察），具单槽。气孔边缘明显，延伸至花粉粒全长。外壁具顶盖柱状。顶盖是不连续的，有许多小穿孔随机分布在整个无孔表面。外壁表面微刺。在大多数种的Trithuria中，有一小部分花粉粒具有一个无沟孔。在两个种中，发现了罕见的非典型颗粒，其外壁具条纹状或部分条纹状的雕刻，这种条纹状的图案与裸鞘属（三白草科，藓目）的外壁雕刻非常相似。倒槽花粉的存在并不与睡莲目中Hydatellaceae的位置相矛盾，但这种花粉类型在其他早期分歧的被子植物和单子叶植物中也很常见。外壁雕刻在水盾草科、水囊草科和睡莲科之间存在差异，但水盾草科两属之间和睡莲科属间的外壁雕刻特征也存在差异。与睡莲目其它科相比，海枣科的花粉形态比较单一。
The small aquatic family Hydatellaceae was recently assigned to the early‐divergent angiosperm order Nymphaeales. Pollen morphology is described using both SEM and LM for all 12 species of Hydatellaceae, and using TEM for one species (T. submersa). These observations are compared with pollen data from the other two families of Nymphaeales, Nymphaeaceae and Cabombaceae, including original observations for both genera of Cabombaceae. No significant interspecific variation in pollen morphology occurs in Hydatellaceae, though both of the perennial species (Trithuria inconspicua and T. filamentosa), which could be apomictic, possess at least partially sterile and collapsed pollen. Pollen of Trithuria is small, oblong or rounded (viewed from the distal pole) and monosulcate. The aperture has a distinct margin and extends the full length of the pollen grain. The exine is tectate‐columellate. The tectum is perforate: discontinuous with numerous small perforations randomly scattered over the entire non‐apertural surface. The exine surface is microechinate. In most species of Trithuria, a small percentage of pollen grains possess a trichotomosulcate aperture. In two species, rare atypical grains with striate or partially striate exine sculpturing were found. This striate pattern is very similar to exine sculpturing in Gymnotheca (Saururaceae, Piperales). The presence of anasulcate pollen does not contradict placement of Hydatellaceae within Nymphaeales, but this pollen type is also common among other early‐divergent angiosperms and monocots. Exine sculpturing differs between Cabombaceae, Hydatellaceae and Nymphaeaceae, but this character also differs between the two genera of Cabombaceae and among genera of Nymphaeaceae. Compared with other families of Nymphaeales, Hydatellaceae are relatively uniform in pollen morphology.