Pollen size in Hickories (Carya)
Pollen size in Hickories (Carya)
复制标题
山核桃树的花粉大小
作者：
D. E. Stone
花粉研究，特别是有关花粉大小频率的研究，受到古植物学家的重视多于系统植物学家。这种兴趣是由于有限的古生态信息，可以通过只知道属的化石花粉。属鉴定允许一些推论的主要条件，但更精细的评价取决于具体的花粉鉴定。而且，一般来说，发现花粉在属内的质量相似性（Erdtman 1952），工作者已经转向花粉大小和孔数作为鉴定种的关键。通过将大小频率数据与现存物种的大小频率数据相关联，尝试对化石松花粉进行特定鉴定（Cain 1940; Cain and Caill 1948）。基于这类研究的概括导致了一些相当深刻的古生态学解释（Whitehead 1962 b）。然而，近年来，由于现代和化石花粉的采样、处理和固定问题，人们对粒度频率研究的可靠性提出了许多质疑（参见Buell 1946; Faegri 1960; Whitehead 1962 b）。假设采样问题可以克服，研究现代山核桃和其他属的花粉在第三纪和更新世沉积物中的代表性可以证明对古植物学家和系统植物学家有价值。Whitehead（1960; 1962 a）和Stachurska（1961）对核桃科花粉的形态进行了研究，但没有对山核桃属进行全面的统计分析。山核桃花粉大小的研究可以作为与化石颗粒比较的标准，因为包括了所有现存的种，除了山核桃，雄花不开花。这项工作的结果已经证明了支持气孔大小和倍性水平之间的相关性的早期发现（Stone 1961）的价值，并且在种或种群的划分方面取得了部分成功。花粉样品的选择，花粉的制备技术，以及在较小程度上测量颗粒的方法，都是必须控制和标准化的因素。正确选择花粉样本需要充分覆盖一个物种发生的地理区域和环境条件，以及考虑单棵树内花粉大小的表型变异。在这项研究中，包括来自美国东南部的大量树木样本。然而，总共有16名美国人。S.美国、北方墨西哥和东南亚都有代表。附有标本采集数据注释的油印纸可应要求提供。我要感谢德尔齐·德马雷博士和韦恩·曼宁教授，感谢他们帮助保护了一些稀有物种，感谢唐纳德·怀特黑德博士在准备手稿时提供了有益的建议。感谢以下植物标本馆馆长借出花粉材料：大英博物馆（自然历史）、国家自然历史博物馆（巴黎）、佛罗里达州立大学、佛罗里达大学、哈佛大学、路易斯安那州立大学、密苏里州植物园、北卡罗来纳州大学、
Pollen studies, especially those concerned with size frequency, have received more attention fronm the paleobotanist than from the systematic botanist. This interest is due to the limited paleoecological information that can be gained by knowing only the genus of the fossil pollen. Generic identifications have permitted some inferences about major conditions, but more refined evaluations depend on specific identifications of pollen. And, generally, finding qualitative similarity of pollen within a genus (Erdtman 1952), workers have turned to pollen size and number of apertures as a key to the identification of species. Specific identifications of fossil pine pollen have been attempted by correlating size-frequency data with that of extant species (Cain 1940; Cain and Caill 1948). Generalizations based on studies of this kind have led to some rather profound paleoecological interpretations (Whitehead 1962b). In recent years, however, many questions have been raised as to the reliability of size-frequency studies that are beset by problems in sampling, treating, and mounting modern and fossil pollen (see Buell 1946; Faegri 1960; Whitehead 1962b). Assuming that the sampling problems can be overcome, studies oln the pollen of modern hickory and other genera well represented in Tertiary and Pleistocene sediments could prove valuable to the paleobotanist and systematic botanist. Both Whitehead (1960; 1962a) anid Stachurska (1961) have surveyed the morphology of the pollen of Juglandaceae, but they did not attempt a comprehensive statistical analysis of Carya. This study of pollen size in Carya could serve as a standard for comparison with fossil grains inasmuch as all extant species are included, except Carya cathayensis Sarg., for which staminate flowers are not knlown. Results of this work already have proved of value in supportingo earlier findings on the correlation between stomatal size and the ploidal level (Stone 1961) and have been partially successful in delimiting species or groups of species. Selection of pollen samples, the technique of preparing the pollen for observation, and to a lesser extent the method of measuring the grains are all factors which must be controlled and standardized. Proper selection of pollen samples requires adequate coverage of geographic areas and environmental situations in which a species occurs, as well as consideration of phenotypic variation in pollen size within a single tree. In this study a large sampling of trees from the southeastern United States is included. All told, however, 16 U. S. states, northern Mexico, and southeastern Asia are represented. Mimeographed sheets with the collection data of annotated specimens are available on request. I wish to thank Dr. Delzie Demaree and Professor Wayne Manning for their help in securing some of the rare species and Dr. Donald Whitehead for offering helpful suggestions in preparation of the manuscript. Appreciation for the loan of pollen material is acknowledged to curators of the following herbaria: British Museum (Natural History), Museum National D'Histoire Naturelle (Paris), Florida State University, University of Florida, Harvard University, Louisiana State University, Missouri Botanical Garden, University of North Carolina, University