杉科植物分类学研究

本文对杉科植物的研究历史作了回顾,根据分支分类结果和表征分类结果,提出了一个新的分类系统。以形态学为依据,结合其他学科的研究成果,对杉科的分类作了订正。作者承认杉科植物共９属、１２种及３变种,将杉木、厚皮杉木、德昌杉木和米德杉木归并,支持柳杉作为日本柳杉的变种、台湾杉木作为杉木的变种、秃杉和台湾杉归并的观点。     

杉科植物的系统发育分析

本文以形态学为依据,参考其他学科的研究成果,用分支分类方法并结合表征分类方法探讨了杉科植物的系统演化关系,提出了新的分类系统。在分支分类中,金松科被选作外类群。主要根据外类群比较原则、化石原则和一般的演化规律,确定了性状的祖征和衍征,采用最大同步法、综合分析法、演化极端结合法及最小平行进化法共四种方法进行分支分析,选择最简约的分支图作为本文讨论基础。在表征分类中,选取59个性状,利用距离系数和类平均法,对金松属和杉科各属进行了聚类运算,得出表征图。综合两种分析结果,主要结论如下:(1)属间关系:柳杉属是现存杉科植物中最原始的类群。水松属和落羽杉属关系密切,二者与柳杉属近缘。巨杉属和北美红杉属关系密切,是中级进化水平的类群。水杉属与巨杉属和北美红杉属的亲缘关系相对较近。杉木属、密叶杉属和台湾杉属关系密切,是杉科植物中的高级进化类群,其中又以台湾杉属演化水平最高。(2)系统排列:支持金松科的成立,将杉科分成5族,即柳杉族(仅含柳杉属)、落羽杉族(含水松属、落羽杉属)、北美红杉族(含巨杉属、北美红杉属)、水杉族(仅含水杉属)和杉木族(含杉木属、密叶杉属及台湾杉属)。     

中国和邻近地区杉科特有植物的核型及其进化水平的初步研究

中国和邻近地区杉科特有植物的核型类型,柳杉属、水松属、水杉属均为“1A”,杉木属、台湾杉属分别为“1B”和“2B”,它们的进化水平似依序递增并组成A-柳杉属——水松属——台湾杉属和L-水杉属——杉木属二条演化路线。该结果得到某些形态学性状和古植物学的支持,基本上适用于整个杉科。     

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(冰杉属、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。     

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。     

中国特有裸子植物的解剖，II．秃杉

台湾杉属Taiwania包括秃杉T．flousiana Gaussen和台湾杉T.cryptomerioides Hayata 两种。秃杉现已列为我国一级国家重点保护植物。本文作者在光学显微镜和扫描电镜下,系统 观察了秃杉营养苗端,叶角质层内、外表面及叶子内部结构,幼茎,茎的次生韧皮部和次生木质 部的结构等。通过对秃杉各营养器官形态结构的观察,并结合有关文献资料,同杉科其它各属作了比较分析,我们不赞同将台湾杉属提升为一个单型科——台湾杉科的主张,而支持Hayata (1906;1907)早期提出的关于台湾杉属应作为杉科中的一个属,其系统位置可介于密叶杉属与杉木属之间的观点。     

秃杉的细胞学研究

本文首次报道秃杉的核型为K(2n)=22=16m+6sm, 3号染色体具“长着丝点区 域”。似具比同属的台湾杉(18m+4sm)进化的趋势。它们均为"2B"。从国产杉科植物的 核型类型看,似见"2B"的台湾杉属与"1B"的杉木属和"1A"的水杉属、水松属、柳杉属的亲缘关系依序由近到远并比它们进化。本作者还观察了秃杉的核仁数目和多微核现象。     

杉科的染色体资料及在系统演化研究中的作用

杉科共由10属(包括金松属)、20种(变种)组成。本文整理了19种(占95％,隶10属)植物的染色体数目和16种(占80％,隶9属)的核型资料,核型的模式图如图1所示。通过对这些细胞学资料的分析,笔者支持2n=20、x=10的金松属从杉科(2n=22、x=11)分立成金松科。根据其他各属间的亲缘关系,本作者认为可以把它们分隶于5个亚科:Ⅰ.柳杉亚科:Cryptomerioideae(Cryptomeria);Ⅱ.落羽杉亚科Taxodioideae(Glyptostroous,Taxodium);Ⅲ.红杉亚科Sequoideae(Metasequoia,Sequoiadendron,Sequoia);Ⅳ.杉木亚科Cunninghamioideae(Cunninghamia,还可能有:Athrotaxis);Ⅴ.台湾杉亚科Taiwainoideae(Taiwania)。这些亚科和属的进化水平依序渐增,它们分别位于进化路线A(亚科Ⅰ、Ⅱ、Ⅴ)和进化路线L(亚科Ⅲ、Ⅳ)上。这些结果是前人的演化系统所没有涉及的,表明了染色体资料在杉科的系统演化研究中起着重要的作用。     

生境的破坏或改变对杉科种属分布的影响

杉科共有10个属16种,其中5个是单种属(水杉属、水松属、巨杉属、北美红杉属、金松属),5个是寡种属(杉木属、台湾杉属、柳杉属、落羽杉属、密叶杉属),两者各占50%。分布于北温带地区,多在东亚和北美洲,仅密叶杉属分布于南半球澳大利亚的塔斯马尼亚。植物与生境是一个互相依存的统一体,而生境的破坏或改变对杉科植物种属分布有严重的影响。在美国加利福尼亚洲现今仅有巨杉和北美红杉两个单种属,这是由于火山爆发留下来,现在仅分布于美国加州部分地区。     

杉木不同无性系过氧化物酶同工酶的研究

本文对杉木（Ｃｕｎｎｉｎｇｈａｍｉａｌａｎｃｅｌｏａｔａ（Ｌａｍｂ．）Ｈｏｏｋ．）不同无性系及其不同株龄的叶和不同发育时期的雄球花进行了过氧化物酶同工酶检测。结果表明：杉木４１４号无性系叶和雄球花的过氧化物酶同工酶酶谱与其它无性系都具明显差异;同－无性系叶与雄球花的过氧化物酶同工酶酶谱存在显著差异;不同发育时期的雄球花的过氧化物酶同工酶存在顺序表达。作者认为：过氧化物酶同工酶作为种内分类的鉴定性状较为合适,而科、属、种的分类依据则应更侧重于形态特征。根据杉木４１４号无性系的过氧化物酶同工酶的特异性及其短叶、叶端钝圆和多雄花等特点,可以把它定为杉科杉属杉木物种的一个变型：多雄花杉木。     

Phylogenetic Analysis of the Family Taxodiaceae

In the present paper,both cladistic analysis and phenetic analysis were conducted to evaluate the phylogenetic relationships of the Taxodiaceae based on an extensive literature review and study of herbarium． In the cladistic analysis,the Sciadopityaceae was chosen as outgroup．The polarity of characters was determined mainly according to outgroup comparison,fossil evidence and generally accepted viewpoints of morphological evolution．By the result of compatibility analysis,character 2(leaf type),which possessed a much higher coefficient than others whether or not its polarity was altered,was deleted． Finally,a data matrix consisting of all the extant nine genera and 24 characters was analyzed using Maximal Same Step Method,Synthetic Method,Evolutionary Extremal Aggregation Method and Minimal Parallel Evolutionary Method,and four cladograms were generated,of which only the most parsimonious one (Fig．1)was presented for discussion. The cladogram shows that the Taxodiaceae are assorted along five lines of evolution： 1)Metasequoia;2)Sequoiadendron,Sequoia;3)Cryptomeria;4)Glyptostrobus and Taxodium;5)Cunninghamia,Athrotaxis and Taiwania． Ten genera(including Sciadopitys)and 59 characters were used in the phenetic analysis．The phenogram(Fig．2)indicates that Sciadopitys is a very distinct group with remote affinity to the other genera,and the Taxodiaceae are divided into four groups：1)Sequoia,Sequoiadendron;2)Athrotaxis,Cunninghamia and Taiwania;3)Cryptomeria,Glyptostrobus and Taxodium;4)Metasequoia． Based primarily on the result of cladistics,with reference to that of phenetics,the main conclusions were drawn as follows：(1)Generic relationships：Cryptomeria should be considered the most primitive genus in the extant groups of the Taxodiaceae. Glyptostrobus and Taxodium, close to Cryptomeria, are sister taxa and relatively primitive groups. Sequoiadendron and Sequoia are closely related and intermediate advanced. Metasequoia is a more or less isolated taxon, relatively close to Sequoiadendron and Sequoia. Cunninghamia. Athrotaxis and Taiwania might represent a single lineage and form a very advanced group, of which Taiwania may be the most specialized. (2) Systematic treatments: The authors support the viewpoint that Sciadopitys should be treated as an independent family, and suggest that the Taxodiaeae should be divided into five tribes. Systematic arrangements are as follows: Taxodiaceae Warming Trib. 1. Cryptomerieae Vierhapper Gen. 5. Sequoia Endl. Gen. 1. Cryptomeria D. Don Trib. 4. Metasequoieae Pilger et Melchior Trib. 2. Taxodieae Benth. et Hook. Gen. 6. Metasequoia Miki ex Hu et Cheng Gen. 2. Glyptostrobus Endl. Trib. 5. Cunninghamieae Zucc. Gen. 3. Taxodium Rich. Gen. 7. Cunninghamia R. Br. Trib. 3. Sequoieae Wettstein Gen. 8. Athrotaxis D. Don Gen. 4. Sequoiadendron Buchholz Gen. 9. Taiwania Hayata     

Karyological Studies in Cunninchamia unicanaliculata and var. pyramidalis

Cunnighamia unicanaliculata D. Y. Wang et H. L. Liu and var. pyramidalis D. Y. Wang et H. L. Lin, two new taxa recently found in south-western Sichuan Province of China, have both a very restricted yet sympatric geographical distribution, including Dechang and Miyi districts.[7] There is a debate as regards the specific status of C. unicanaliculata. A comparative karyological investigation, including chromosome numbers, karyotype analyses and measurements of nuclear volume and DNA contents, was under- taken in order to shed some light on the phylogenetic relationships between these taxa and C. lanceolata (Lamb.) Hook. The kaxyotype formulas of the above two taxa and C. lanceolata are as follows: C.unicanaliculata; K(2n) = 22 =L8m+ S12m+S2sm; C. unicanaliculata var. pyramidalis: K(2n)= 22= L8m +S10m+S4sm; C. lanceolata (Type A): K(2n) =22 = Lsm+ S14m S2sm; C. lanceolata(TypeB): K(2n) = 22 = L8m + S14m . Frown the above karyotypes, we have found that C. unicanaliculata and var. pyrami- dalis, which are very similar to each other, are closely related to C. lanceolata (Type B), but seem more strongly differentiated in the following respects: (1) the former posses- sing 1--2 pairs of chromosomes with submedian primary constrictions each, while the latter with all chromosomes possessing median primary constrictions; (2) the satellites of the former being always located on the 4th pair of chromosomes, whereas the position of satellites of the latter varying with geographical distribution, being usually on the 1st and 4th pairs of chromosomes; (3) B-chromosomes being present in the latter (predominantly in the geographical races of southwestern China) but not seen in the former; (4) the average chromosome volume of C. unicanaliculata var. pyramidalis being 623.44, while those of the four geographical races of C. lanceolata being 667.2–796.0; (5) the comparative DNA amount of C. unicanaliculata var. pyramidalis being 5.54, while those of the various geographical races of C. lanceolata being 6.20–7.67. Upon an overall comparison of the data with regard to karyology, geographical distribution, ecology, morphology and isoenzymic patterns of the taxa in question, we come to the following conclusions. Cunninghamia unicanaliculata and var. pyramidalis are most likely taxa originated from natural populations of C. lanceolata. The extreme environmental conditions of the habitats axe thought to have played an important role in the production of these two new taxa. An elevation of over 2000 meters and the periodical aridity of climate of the habitat, which differed remarkably from those of C. lanceolata, made possible the isolation of alternative populations, accompanied by selection for adaptation to extreme environments. But the differences between these two newly found taxa and C. lanceolata are karyologically minor and morphologically quantitative and tend to display a more or less continuous variation pattern. It is, therefore, suggested that they are probably geographical races or ecotypes of C. lanceolata, and are not distinct enough from the latter to warrant specific status. It seems best to treat both C. unicanaliculata and var. pyramidalis as infraspecific catorories of C. lanceolata.     

The chromosomes ofCunninghamia konishii,C. lanceolata,andTaiwania cryptomerioides (Taxodiaceae)

Karyotype analyses were conducted onCunninghamia konishii, Cunninghamia lanceolata, andTaiwania cryptomerioides, all members ofTaxodiaceae. The somatic chromosome number was found to be 2n = 2x = 22 in all species which concurrs with previous reports. The karyotypes are generally asymmetrical with the smaller chromosomes being more submedian than the larger ones. Chromosomes with unusual or specific structures, thought to be associated with the nucleolar organizing region, were found in each species.Cunninghamia species have a marker chromosome pair with an unusually long secondary constriction.Taiwania has an unusually long kinetochore region present in a submedian chromosome pair.     

Anatomy of Gymnosperms Endemic to China,II. Taiwania flousiana Gaussen (Taxodiaceae)

Taiwania Hayata contains two species: T.flousiana Gaussen and T. cryptomerioides Hayata, both endemic to China. T. flousiana was investigated with both light and scanning electron microscopes in respect to shoot apex, external and internal surfaces of leaf cuticle, primary leaf, juvenal and mature leaves, young stem, secondary phloem and wood of stem, etc, It is shown that the shoot apex consists of the following five regions: (1) the apical initials; (2) the protoderm, (3) the subapical moher cells;. (4) the peripheral meristem, and (5) the pith mother cells. The periclinal and anticlinal division of the apical initials takes place with approximately equal frequency. The juvenal leaf is nearly triangular or crescent-shaped in cross section and belongs to the leaf type II. The mature leaf is quadrangular in cross section (the leaf type I). There are a progressive series of changes in size and shape of the leaf cross section. The stoma of the mature leaf is amphicyclic and occasionally tricyclic. The crystals in the juvenal leaf cuticle are more abundant than those in the mature leaf cuticle. The transfusion tissue conforms to the Cupressus type. The structure of juvenal leaf is the nearest to that in Cunninghamia unicanaliculata D. Y. Wang et H. L. Liu, while the mature leaf is similar to that of the Cryptomeria. Sclerenchymatous cells of the hypodermis in the young stem comprise simple layers and are arranged discontinuously. No primary fibers are found in the primary phloem. Medullary sheath is present between the primary xylem and the pith. There are some sclereids in the pith. The secondary phloem of the stem consists of regularly alternate tangential layers of cells in such a sequence: sieve cells, phloem parenchyma cells, sieve cells, phloem fibers, sieve cells. The phloem fiber may be divided into thick-walled and thin-walled phloem fiber. The crystals of calcium oxalate in the radial walls of sieve cells are abundant. Homogeneous phloem rays are uniseriate or partly biseriate, 1-48 (2-13) cells high, and of 26-31 strips per square mm. Growth rings of the wood in Taiwania are distinct. The bordered pits on the radial walls of early wood tracheids are usually uniseriate, occasionally paired and opposite pitting. Wood parenchyma is present, and its cells contain brown resin substances. Their end walls are smooth, lacking nodular thickenings. Wood rays are homogeneous. Cross-field pits are cupressoid. Resin canals are absent. Based on the anatomy of Taiwania and comparison with the other genera of Taxodiaceae, the authors consider the establishment of Taiwaniaceae not reasonable, but rather support the view that the genus is better placed between Cuninghamia and Arthrotaxis in Taxodiaceae.     

Two Evolutionary Lines of Taxodiaceae

According to the karyotypic data the present author proposes two evolutionary lines, A and L (Fig. 1), in Taxodiaceae (Exclud. Sciadopitys). The former is characterized by a relatively rapid increase of the mean arm ratio but a relatively slow rise of the ratio of the longest chromosome to the shortest one and it is composed of Cryptomeria, Glyptostrobus, Taxodium and Taiwania, which advance from primitive to progressive in the order. The latter is characterized by, on the contrary, a relatively slow increase of mean arm ratio and a relatively rapid rise of the ratio of chromosome size and it comprises Metasequoia, Sequoiadendron, Sequoia and Cunninghamia (probably Athrotaxis also), which advance in the order. The inference is supported by the data from morphology, anatomy, embryology and so on.Key words Taxodiaceae; Karyotype; Evolutionary line     

Phylogenetic relationships in Taxodiaceae and Cupressaceae sensu stricto based on matK gene, chlL gene, trnL-trnF IGS region, and trnL intron sequences

Nucleotide sequences from four chloroplast genes, the matK, chlL, intergenic spacer (IGS) region between trnL and trnF, and an intron of trnL, were determined from all species of Taxodiaceae and five species of Cupressaceae sensu stricto (s.s.). Phylogenetic trees were constructed using the maximum parsimony and the neighbor-joining methods with Cunninghamia as an outgroup. These analyses provided greater resolution of relationships among genera and higher bootstrap supports for clades compared to previous analyses. Results indicate that Taiwania diverged first, and then Athrotaxis diverged from the remaining genera. Metasequoia, Sequoia, and Sequoiadendron form a clade. Taxodium and Glyptostrobus form a clade, which is the sister to Cryptomeria. Cupressaceae s.s. are derived from within Taxodiaceae, being the most closely related to the Cryptomeria/Taxodium/Glyptostrobus clade. These relationships are consistent with previous morphological groupings and the analyses of molecular data. In addition, we found acceleration of evolutionary rates in Cupressaceae s.s. Possible causes for the acceleration are discussed.     

森林叶凋落物混合分解的研究Ⅰ.缩微(Microcosm)实验

采用缩微实验法,初步系统研究了杉木叶凋落物分别与火力楠、红栲和木荷3个阔叶树种之一的叶凋落物两两混合分解的动态变化,以探明凋落物混合分解过程中可能存在的相互作用.结果表明,杉木叶凋落物与3种阔叶树种叶凋落物两两混合分解时所表现出不同的相互作用形式:杉木与木荷表现出抑制作用,杉木与红栲或火力楠表现为较弱的促进作用.     

森林叶凋落物混合分解的研究I.缩微(Microcosm)实验

采用缩微实验法 ,初步系统研究了杉木叶凋落物分别与火力楠、红栲和木荷 3个阔叶树种之一的叶凋落物两两混合分解的动态变化 ,以探明凋落物混合分解过程中可能存在的相互作用 .结果表明 ,杉木叶凋落物与 3种阔叶树种叶凋落物两两混合分解时所表现出不同的相互作用形式 :杉木与木荷表现出抑制作用 ,杉木与红栲或火力楠表现为较弱的促进作用 .