杉科的细胞分类学和系统演化研究

根据杉科的核型资料,本文(1)提出“1B”可能是一个新的高等植物核型类型;(2)讨论了各属的有关分类学问题及相互亲缘关系,它们的进化顺序可能是柳杉属、水松属、落羽杉属、水杉属、巨杉属、红杉属、杉木属(密叶杉属与之近缘)、台湾杉属;(3)支持金松属分立成金松科,它可能比杉科各属原始; (4)红杉(AAAABB)的亲本可能是二个古代种“水杉”和“巨杉”,它们的直接后裔或留下的近缘是水杉和巨杉;(5)杉科存在A和L两条进化路线,前者包括柳杉属、水松属、落羽杉属、台湾杉属;后者包括水杉属、巨杉属、红杉属、杉木属(密叶杉属);(6)提出一个杉科新系统(包括一个新亚科):Ⅰ.柳杉亚科(柳杉属),Ⅱ.落羽杉亚科(水松属、落羽杉属),Ⅲ.红杉亚科(水杉属、巨杉属、红杉属),Ⅳ.杉木亚科(杉木属、密叶杉属),Ⅴ.台湾杉亚科,新亚科(台湾杉属)。本文还对前人的杉科系统作了讨论。     

扁柏属的核型及柏本亚科的细胞分类学研究

分析了美国扁柏、日本扁柏和日本花柏的核型,它们的核型公式分别为Ｋ（２ｎ）＝２２＝２２ｍ,２０ｍ＋２ｓｍ和１４ｍ＋８ｓｍ。作者比较了扁柏属６个代表种的核型,发现北美种类有比东亚种类原始的趋势。在柏本亚科中,扁柏属可能最进化,柏木属最原始,福建柏属和杂交属×Ｃｕｐｒｅｓｓｏｃｙｐｅｒｉｓ居中。论文还讨论了柏木和福建柏的系统位置。     

雪松属的细胞分类学及历史植物地理学研究

雪松属含雪松,北非雪松、黎巴嫩雪松和短叶雪松等４种,它们间断分布于西北喜马拉雅、西北非及西亚。本文分析了雪松的核型,Ｋ（２ｎ）＝２４＝１８ｍ＋６ｓｍ,该结果与Ｈｉｚｕｍｅ（１９８８）的一致但不同于Ｍｅｈｒａ＆Ｋｈｏｓｈｏｏ（１９５６）的。作者比较了雪松属３个代表种的核型并提出了它们的进化趋势可能是雪松→北非雪松→黎巴嫩雪松。从松科各属核型的比较分析,作者认为将雪松属由落叶松亚科分出置于冷杉亚科是合乎需要的。根据细胞学、化石、地理分布、古地理和古气候等资料,本文还讨论了雪松属的起源、迁移和进化。     

侧柏亚科三种植物的核型及其细胞分类学研究

分析了北美乔柏、北美香柏和西方翠柏的核型,它们的核型公式分别为Ｋ（２ｎ）＝２２＝１６ｍ＝１６ｓｍ（２ＳＡＴ）,２０ｍ（２ＳＡＴ）＋２ｓｍ和２０ｍ（２ＳＡＴ）＋２ｓｍ。北美乔柏的核型为首次报道。经对侧伯亚科１０个属（２２种）的核型的比较分析,似见南半球５属和侧柏属及Ｔｅｔｒａｃｌｉｎｉｓ最为原始,罗汉柏属和崖柏属最进化,翠柏属居中。本文还讨论了翠柏属、侧柏属及南半球属的分类位置。     

SYSTEMATIC STUDIES IN THE LEAF ANATOMY OF PALM GENUS SYAGRUS

A systematic survey of the leaf anatomy of 51 taxa in the palm genus Syagrus was made. Cross sections of the middle pinnae of each taxon were embedded, cut, stained, and mounted on slides. Criteria used to distinguish species were based mainly on differences in the laminar surface and hypodermis: frequency and location of various sized veins; frequency, shape, and location of nonvascular fibers; size and shape of midrib and main vascular bundle; and size and shape of expansion cell tissue. The included key to the species employs mostly these characteristics. Each taxon is listed under subgenera and sections in the order presented in a previous article, where gross morphology was used as the basis of classification. Relationships between species of each subgenus and section are discussed in terms of the original arrangement of each group and needed changes. It is significant that certain evolutionary sequences have become unfolded which were not apparent by use of morphological characters alone. Although all relationships have not been completely worked out, this survey has resulted in a revision of my original classification of the genus Syagrus and at the same time has also corroborated certain alignments of species previously based on gross morphology.     

高体PangPi咽齿个体发育过程及其系统学意义

鱼类为5-5齿式,主行齿数目为最普通的形式。但鳑鲏鱼类咽齿全部为单行,没有2或3行咽齿存在,咽齿的形态也表现出光滑和有锯齿的变异,显示出一定的独特性。Nakajima对琵琶湖中高体鳑鲏的咽齿替换过程作了简单描述［1］。由于方法和材料的限制,在他的研究中没有早期的材料。本研究采用人工受精、孵化和室内养殖的方式,从早期材料开始,观察咽齿替换的模式和形态变化,同时对比养殖情况下,自然产卵在蚌内,孵化发育后刚从蚌体游出的仔鱼材料,分析高体咽齿发育的系统学意义和生态适应。     

中国壁虎属动物系统学研究进展

壁虎属动物是一种分布非常广泛的动物,在我国除东北外其它各地都有分布。本文主要对国内壁虎属动物分类及系统学研究进行了总结,提出了壁虎属动物该方面研究现状和存在的问题。     

CYTOTAXONOMY OF THE CHARACEAE: KARYOTYPE ANALYSIS OF NITELLA OPACA AND NITELLA FLEXILIS

The haploid chromosome complement of Nitella flexilis (n = 12) is composed of two quite different basic karyotypes. One of these is symmetrical and appears to be identical to the karyotype of N. opaca (n = 6), and the other is quite asymmetrical and seems to be identical to that of an apparently undescribed dioecious Nitella from Kansas (n = 6). This may indicate that the monoecious N. flexilis has arisen through hybridization between two dioecious species. Although heteromorphic sex chromosomes were not observed in either species, it appears that female and male potentialities are confined to separate basic chromosome complements and mechanisms determining the monoecious and dioecious states are in close relation to ploidy.     

HYBRIDIZATION AND CYTOTAXONOMY OF DICENTRA

Biosystematic relationships among species assigned to three subgenera of the genus Dicentra were investigated with respect to hybridization and chromosomal constitution and fertility of the hybrids. Four species of subgenus Dicentra, D. formosa, D. eximia, D. nevadensis, and D. peregrina, were intercrossed in various ways to form diploid, triploid, and tetraploid hybrids. Hybrids at the tetraploid level in this subgenus invariably were highly fertile. Triploid hybrids, as expected, were mostly very sterile. Diploid hybrids varied in this respect, but none was highly fertile. Crosses with two of the remaining four species of subgenus Dicentra produced no hybrids, but abundant seed was obtained in one instance. The two species of the subgenus Chrysocapnos, D. chrysaniha and D. ochroleuca, cross to produce a partially fertile tetraploid hybrid, but cross-pollinations involving these species with those of other subgenera failed. The single species of subgenus Hedycapnos, D. spectablis (diploid) produced no hybrids when cross-pollinated with members of the other two sections. These results are fully concordant with presumed affinities based on morphological similarity In addition, preliminary results of hybridization between the monocotyledonous D. peregrina and a number of dicotyledonous species of Dicentra are reported.     

THE CYTOTAXONOMY OF FILIPENDULA (ROSACEAE) AND ITS IMPLICATIONS

The genus Filipendula Mill. is generally separated from Spiraea L. in systematic keys on the basis of a single fruit character. In some taxonomic treatments of the Rosaceae, where subfamilies are used, this places the genera in separate subfamilies. Karyological studies can be useful in assaying the justifiability of such treatment and are needed because of serious discrepancies between previous reports of chromosome numbers and the recent textbook designation, on dubious grounds, of F. vulgaris as an example of a “permanent chromosome hybrid.” The results given in this paper show that x = 7 in this genus (compared with x = 9 in Spiraea) and the reasons for rejecting previous counts of 2n = 15 for F. vulgaris are presented. “Permanent chromosome hybridity” for this species is also rejected. The possibility that a cytotype with 2n = 16 may exist in the northern part of the range of F. ulmaria cannot be completely discounted, but positive evidence is presented for 2n = 14 in this species (even though 2n = 16 has been reported most frequently recently). The basic number 7 for Filipendula is in agreement with the placing of this genus in the subfamily Rosoideae even though the hereditary peculiarities (apomixis and permanent chromosome hybridity) shown by some other members of this subfamily are apparently not now needed to explain the cytological situation in Filipendula.