Palynomorphological and taxonomical investigations of some Apiaceae taxa from Bilecik, Turkey

The objective of the present study is to investigate pollen morphology and taxonomy of some Apiaceae species in Bilecik, Turkey. The study area is restricted to Vezirhan in the south (Bilecik), Pamukova and Geyve in the north (Sakarya), İznik in the west (Bursa), Gölpazarı in the south-east (Bilecik) and Taraklı in the east (Sakarya). Apiaceae species were collected from the study area by visiting there in all four seasons. In this study, the pollen morphology of 22 taxa belonging to different genera of the Apiaceae family was investigated for the first time in detail using light microscope and scanning electron microscopy (SEM). The pollen is radially symmetrical, isopolar and tricolporate in all examined species. Pollen grains are perprolate, prolate and subprolate with the polar axis ranging from 17.53 µm (Non-acetolysed: N) and 18.28 µm (Acetolysed: A) to 39.71 µm (N) and 39.72 µm (A) and the equatorial axis from 11.77 µm (N) and 12.2 µm (A) to 23.77 µm (N) and 23.54 µm (A). The polar shapes of the studied taxa are triangular. Exine ornamentations of four pollen types have been observed by SEM. Two main groups were revealed in the dendrogram which was constructed by using Average Linkage from the examined data. It was determined that some pollen characteristics of investigated Apiaceae taxa are supporters of the classification of taxa with other taxonomical characteristics. Also, three components of investigated palynological characteristics were identified with principal component analysis. Polar axis (P), equatorial axis (E), the ratio of polar axis to equatorial axis (P/E) (pollen shape) and ornamentation in the polar and equatorial views are determined as the most important palynological characteristics for discrimination of the Apiaceae taxa.

本研究旨在探究土耳其比莱吉克（Bilecik）地区部分伞形科（Apiaceae）物种的花粉形态与分类学特征。研究区域限定为南部的韦齐尔汗（Vezirhan，比莱吉克省）、北部的帕穆科瓦（Pamukova）与盖夫（Geyve，均属萨卡里亚省）、西部的伊兹尼克（İznik，布尔萨省）、东南部的格尔帕扎里（Gölpazarı，比莱吉克省）以及东部的塔拉克勒（Taraklı，萨卡里亚省）。研究人员于四季遍历该研究区域，采集伞形科物种样本。本研究首次借助光学显微镜与扫描电子显微镜（SEM），对隶属于伞形科不同属的22个分类单元的花粉形态开展了详细研究。所有受试物种的花粉均呈辐射对称、等极且具三孔沟结构。花粉粒分为超长球形（perprolate）、长球形（prolate）与近长球形（subprolate）三类，极轴长度范围为17.53 µm（未乙酰解组，Non-acetolysed: N）与18.28 µm（乙酰解组，Acetolysed: A）至39.71 µm（N）与39.72 µm（A）；赤道轴长度范围为11.77 µm（N，12.2 µm A）至23.77 µm（N）与23.54 µm（A）。受试分类单元的极面观呈三角形。通过扫描电子显微镜可观察到4种花粉类型的外壁纹饰。基于受试数据采用平均连接法构建的聚类树状图显示出两个主要类群。研究发现，所调查的伞形科分类单元的部分花粉特征，可与其他分类学特征共同支撑该类群的分类系统。此外，通过主成分分析（principal component analysis）识别出3个核心孢粉学特征组分。极轴长度（P）、赤道轴长度（E）、极轴与赤道轴之比（P/E，即花粉形状）以及极面观与赤道面观的纹饰特征，被确定为区分伞形科分类单元的关键孢粉学特征。