摘要
由于天然种间杂交 ,猕猴桃属ActinidiaLindl.的分类存在着组间界限不清、近缘种之间很难区分的问题。本文试图通过对该属不同组、系的植物花粉及种间杂交后代花粉的扫描电镜观察 ,探讨该属物种的系统学关系。在扫描电镜下观察了猕猴桃属植物 2 1种、6变种和 4个不同种间杂交F1 代植株的花粉 ,描述了它们的花粉形态 ,并根据花粉形态特征建立了相应的检索表。研究结果表明 :( 1 )猕猴桃属的花粉形状主要以长球形至近球形为主 ,变异较小 ,而花粉粒大小和外壁纹饰的种间差异较大。 ( 2 )多数迁地保护物种的花粉粒以三孔沟为主 ,不同于以前报道的以三拟孔沟为主 ,原因可能是花粉样本采集地的环境不一样 ,以及野外的广泛杂交造成的。 ( 3)种间杂交后代花粉空瘪 ,无授粉能力 ,是由于所采用亲本植株染色体的倍性不同 ,后代不能产生正常花粉所致。 ( 4 )人工选育雄株花粉外壁纹饰较野生雄株花粉的精细 ,这种花粉外壁纹饰变小的特征可能有利于雌雄异株植物的授粉受精。这一现象值得进一步探讨。 ( 5 )雄株花粉大小与其雌株果实大小之间有一定相关性 ,这一现象有助于杂交后代的早期筛选。
There exist many taxonomic uncertainties in the genus Actinidia Lindl. as to the circumscription of sections and treatment of closely related species because of natural interspecific crossing. Little has been attempted to use micromorphological characters to address the problems. Pollen morphology of 21 species, 6 varieties and 4 interspecific hybrids (F-1) of the genus Actinidia was studied using SEM. A detailed description of the pollen grains was presented and a key to the species of the genus was given based on the pollen morphology observed. The results were summarized as follows: (1) The pollen grains are mainly prolate to subspheroidal in shape, and there were less distinct interspecific differences in the shape than those in size and ornamentation. (2) Most species introduced from the wild have three colporate apertures rather than three colporoid apertures as previously reported, the reason for which could be presumed that the pollen materials observed were harvested from specimens collected from different places with different habitats and that the plants might have undergone various crossings in the wild. (3) The pollen grains of interspecific hybrids were hollow and infertile, which may be due to the different ploidy levels between the parental species, a phenomenon common in the genus Actinidia. (4) The pollen of cultivated staminate varieties was compared with that of the wild types, and the ornamentation became finer than that of the later ones. This characteristic was presumed to be an important evolutionary trait beneficial to pollination in dioecious. plants, a phenomenon which is worthy of further study. (5) The pollen size of male plant individuals is found to be somewhat correlated with the fruit size, a phenomenon which may be helpful for early selection of hybrids.
出处
《植物分类学报》
CSCD
北大核心
2004年第3期245-260,共16页
Acta Phytotaxonomica Sinica
基金
国家自然科学基金 (3 0 0 70 0 82 )
中国科学院生物科技特别支持项目 (STZ_0 1_3 4)~~
