摘要
通过光学显微镜(LM)和扫描电子显微镜(SEM)观察表明,红树(Rhizophora apiculata)花粉粒赤道面的形状为球形-近球形,极面观为圆三角形,偶见圆四方形,3-4孔沟,具有连续的环赤道内孔,花粉外壁的典型纹饰为细网状-皱纹状(microreticulate-rugulate)。作者首次报道红树花粉的多态现象,其花粉外壁纹饰和萌发孔数量存在显著的变异,SEM观察到花粉外壁纹饰的变异主要是孔状(perforate)、皱纹状(rugulate)和穴状(foveolate)等类型,LM观察发现4个萌发孔的花粉变异类型。花粉形态的观察与描述为化石花粉的鉴别提供了不可或缺的对比依据。研究红树的花粉形态和发现多态现象有助于了解红树科红树属的花粉外壁演化。花粉的多态现象表明单个花粉形态特征并不能完全代表种的特征。花粉的分类也应该充分考虑花粉性状的间断和连续性,以期正确认识花粉性状在种群内的变异和变异式样,达到客观认识和正确划分植物种下等级的目的。花粉的多态现象为化石花粉的种类鉴定增加了新的参考信息,作者也讨论了花粉多态现象在植物系统演化和古生态学等研究中的可能价值与意义。
Pollen polymorphism has been widely described in terms of variations of exine sculptural pattern and aper- ture shape, position, characteristics and its number. So far no documents on RhizoPhora apiculata BI. （Rhizophora- ceae） pollen variation below species level have been reported. We reexamined pollen morphology of R. apiculata based on LM and SEM observations, and present new observation result on its pollen polymorphism. Precious pollen morphological study documented that Rhizophora pollen are characterized hy tricolporate with zonate endoaperture, ornamentation finely reticulate, the reticulum becoming progressively less distinct from pole to equator. Our observa- tion shows that equatorial view of R. apiculata pollen is generally spheral subspheral （P/E= 1.08--1.10）, and with 3--4 colporates, equatorially elongated endoaperture, mediate size of （20.04-- 28.01） 24.43 ×22.56μm （19.61 -- 27.75） （P×E, N=50, LM）, colpus length of 12.64 ± 1.69μm with rugulate membrane, porate length and width of 2.36±0.46 μm and 1.36±0.32 μm, respectively, exine thickness of 2.18±0.64 μm（N=7）, ectexine thicker than endexine. Pollen exine shows frequent sculpture pattern of microreticulate-rugulate, and with significant variation as well. We define the exine sculpture variation as three main types, namely perforate, rugulate and foveolate. We also found tetraeolporated pollen within the sample under LM. Pollen variation in this species is probably related to poly- morphism of the exine sculpture below the pollen sac level. Our detailed examination on R. apiculata pollen yields useful information on pollen morphology and variations, which may facilitate the taxonomic and palynological study on this genus.
出处
《微体古生物学报》
CSCD
北大核心
2008年第4期393-403,共11页
Acta Micropalaeontologica Sinica
基金
国家教育部“留学回国人员科研启动基金”资助(200724)
现代古生物学和地层学国家重点实验室基础性课题
国家自然科学基金
关键词
红树
花粉形态
外壁纹饰
种内变异
多态现象
Rhizophora apiculata BI., pollen morphology, exine sculpture, infraspecific variation, polymorphism
