中国北方孢粉形态查询数据库的构建及杨树、柏树花粉研究

【作者】 贾红娟；

【导师】 许清海；

【作者基本信息】 河北师范大学 ， 自然地理学， 2007， 硕士

【摘要】 花粉分析的基础是花粉鉴定的准确性,但我国供花粉鉴定参照的花粉形态图版一直沿用上世纪60-90年代出版的书籍,且书中囊括的花粉植物种类相对中国分布的数十万种植物显的太少,无法满足现代花粉学研究的需要。为此,在导师的指导下,利用日本OlympusBX51光学生物显微镜和数码显微照相设备,对中国北方75个科201属308种植物花粉的极面观、赤道面观、孔沟、表面纹饰、孢粉壁结构、以及特殊结构进行显微照相,利用filemaker软件对花粉照片进行管理,建成中国北方可查寻孢粉数据库。数据库通过网络可供多个用户使用。课题组内部用户可在Client/ Server方式下浏览系统,需安装客户端软件;浏览用户使用Browser/Server方式,在Web浏览器下可直接浏览所需花粉图档信息。为从事花粉学研究人员提供了快速查询的网络电子图版。杨树、柏树是中国北方常见的乔木植物树种,但这两种植物的花粉形态在光学显微镜下不易区分,地层中也常与一些低等植物孢子混淆。为此,进行这两种植物花粉形态光学显微镜和扫描电镜对比研究,为地层花粉鉴定提供这两种植物花粉的形态特征。光学显微镜下测量了5种杨树、3种柏树各50粒花粉的面积、扁圆率、极轴长度、赤道轴长度,计算了极轴长度/赤道轴长度的比值;做了5种杨树、3种柏树花粉光镜和扫描电镜照片。光镜下观察结果显示,8种花粉均属球形花粉,其中杨树花粉多在10μm～25μm之间属小型花粉;柏树花粉在25μm～50μm之间属中等花粉。杨树花粉为颗粒状或网状纹饰,柏树花粉壁比杨树花粉壁光滑。在光镜下通过大小和纹饰能区分杨树和柏树花粉。扫描电镜图能区分杨属不同种,但柏树不同种较难区分。对8种花粉的面积作了方差分析,结果显示用面积在99%置信水平上能区分8种花粉。5种杨树花粉取扁圆率平均值、极轴平均值、赤道轴平均值、P/E(极轴平均值/赤道轴平均值)值几个参数做聚类分析,结果显示5种杨树可分成3组,加拿大杨和小叶杨是一组,毛白杨和山杨是一组,青杨单独一组。电镜观察纹饰特点与聚类分析结果一致。柏树仅圆柏花粉多具一小圆形萌发孔,其它未见萌发孔;纹饰呈颗粒状,圆柏花粉颗粒纹饰最明显,刺柏次之,侧柏最不明显。根据Walker对花粉纹饰、萌发孔演化趋势结论,推测侧柏最原始,刺柏次之,圆柏进化;青杨花粉网状纹饰明显,其他几种均为颗粒纹饰,同理,青杨较其它杨树更进化,杨树属植物的分化在花粉上已有表现。杨树、柏树花粉外壁较薄,纹饰在光镜下不清晰,这些形态特征使杨树、柏树花粉易褶皱、破碎,褶皱、破碎的花粉可能更易遭细菌破坏、酸碱腐蚀及氧化破坏;另外褶皱的花粉较难鉴定。因此地层中鉴定出的杨树、柏树花粉少。更多还原

【Abstract】 The accuracy identify of pollen is the foundation of pollen analysis, but the reference materals for pollen identification were still followed 60-90’s books of last century, and were less compared to the numerous plants of China. It can’t satisfy the demand of modern pollen research. For this reason, under the supervisor’s instruction, 308 pollen species of 201genera of 75 families in northern China was statisticed with 400 times microscope, and take photos using Japanese Olympus digital camera. Photos are taken on polar view, equator view, aperture, surface, wall structure, unique feature respectively. Then cut pollen photos with the Photoshop software, and construct pollen morphology database use filemaker software. This database provides functions of browse information through the WEB. The home customers browse and manage the system under Client/ Server mode, need to install customer software. Who just browse system under Browser/Server mode do not need to install customer software, can search the diagram file information directly use Web browser. This database provides Web plate to the research personnel.Cupressaceae and Populous is the popular arbor of northern China, but their pollen is not easily distinguished under the optical microscope, and often confuse with some spore. So we do this research contrast of optical microscope and scanning electricity microscope to provide morphology for pollen identification. Pollen grains of three species of cupressaceae and five species of Populous were examined in detail using digital photographic technique and MATLAB software. For each pollen type, 50 pollen grains were measured for their size (maximum and minimum), areas, eccentricity, P/E (pole-length/equator-length) and standard deviation of area respectively. Results show all pollen grains of 8 species are spheroid. Populus pollen size issmall range from 10μm to 25μm with granulate or reticulate decorate. Cupressacea pollen size is medium range from 25μm to 50μm with smooth and psilate decorate.From size and surface decorate Cypressaceae pollen and populus pollen can be distinguished by optical microscope. Different pollen species of populus can be easily distinguished by scanning electron microscope, but different genus of cypressaceae is difficult to distinguish. The Variance Analysis of the areas of eight pollen species shows that it can distinguish the eight pollen species with a reliability of 99 percent. The Cluster analysis of mean eccentricity, pole-length, equator-length and P/E parameter of five species of populus shows that the five species of Populus can be divided into three groups. Populus canadensis and P. simonii belong to one group, P. tomentosa and P. davidiana in another group, P. cathayana alone as the third group. This outcome is consistent with researchers’discovery on scanning electron microscope. Some pollen grains of Sabina chinensis have one aperture, and other kind Cypressaceae pollen can’t find this feature. Pollen of Sabina chinensis has granulate decorates obviously. It doesn’t evident on Juniperus formosana and unclear on Platycladus orientalis. According to Walker’s conclusion of pollen evolve trend about aperture and surface decorate, we speculate that Platycladus orientalis is the primordial, then Juniperus formosana, and Sabina chinensis is more development.Populu cathayana. is distinct different from other species of Populus by it’s reticulate surface. Other Populus species are granulate surface. It indicates the differentiation of Populus embodiment in the pollen. With the same reason found by Walker, we speculate that Populus cathayana is more evolved than other Populus species. Pollen sexine of Cupressaceae and Populous is very thin. This make it easy to crumpledor crushed then may pave the way for chemical and biochemical factor to completethe total decomposition process of the crumpled or crushed grains. Crumpled pollen is difficult to identify, so there is low recovery of this kind pollen in fossil record.更多还原