水杉(杉科)的叶表皮结构

研究了采自北京,上海和聊城（山东省）的水杉叶片,叶上下表皮细胞特征一级;从叶顶部到基部,表皮细胞壁有“直-弯曲-直”的趋势,但具有直或稍微弯曲的表皮细胞壁的区域只占整个表皮面积的很小部分,气孔的数量和分布在叶的上下表面明显不同;在某些叶片,上下表面均有气孔分布,但上表面只有1-100个气孔分布在叶片顶部或极少数分布在基部,气孔分布区只占整个上表皮面积的一小部分,有些叶片上表皮无气孔分布,在所有获得的表皮中,下表皮气孔数量睡分布变化不大,中脉两侧从顶部到基部各分布3-8列气孔,没有发现叶片上表面气孔有无或分布差异与北京,上海和聊城三个采集点之间以及与叶片在同一植株不同位置的相关性,杉科的许多属种在叶片的形态和排列上相似。化石标本又多为枝叶形式,有时难以区分,水杉叶表皮结构的研究为杉科化石植物的分类,提供了表皮特征的参照标准。同时气孔参数的获得为研究大气二氧化碳浓度的变化提供了相关数据。     

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)。     

杉科植物的起源、演化及其分布

本文根据对杉科的系统发育、现代分布和化石分布的研究,结合古地理和古气候资料,讨论了杉科的起源、演化和现代分布格局的成因。杉科基本上是一个亚热带科,我国长江、秦岭以南至华南一带是其现代分布中心。东亚中高纬度的东北地区可能是其起源中心和早期分化中心。起源时间为早侏罗纪或晚三叠纪。杉科植物的各种类型很可能在早白垩纪甚至晚侏罗纪就已分化出来。杉科植物于东亚起源后,在当时劳亚古陆尚未完全解体、气候分带现象尚不甚明显的情况下跨越欧亚大陆散布到北美,并扩散到南半球。自晚白垩纪,白令陆桥和北大西洋陆桥对其在北半球的散布发挥了重要作用。杉科植物目前虽处于衰退状态,但在地质史上却曾经经历过极其繁盛的时代。在中生代中晚期和早第三纪,杉科植物种类繁多,广布于北半球,向北扩散到北极圈内的高纬度地区,是当时的大科。大多数现存属曾分别有过3个或2个分布中心：水松属、落羽杉属和北美红杉属在东亚、北美西部和欧洲;水杉属在东亚和北美西部;柳杉属、杉木属,很可能也包括台湾杉属在东亚和欧洲;巨杉属在欧洲、北美和东亚。在晚白垩纪和第三纪,现存属特别是水松属、落羽杉属、水杉属、北美红杉属和巨杉属,曾是北半球森林植被的重要组成成分。南半球也曾有少量种类,分布亦远较现代普遍。杉科在白垩纪的多样性达到鼎盛,具所有的现代属和大量的化石器官属,但在以后漫长的历史发展过程中,由于地质变迁、气候变化,大量类群绝灭。晚第三纪全球性的气温下降迫使杉科逐渐从高纬度地区撤出。第四纪冰期气候的剧烈恶化使杉科分布区进一步显著退缩至中、低纬度地区,最后在欧洲全部消失,仅在东亚、北美及澳大利亚的少数几个植物 “避难所”中残存下来。现今各属多分布于环太平洋地区极为狭窄的局部范围,在分布区内呈现出孤立或星散的残遗分布式样。杉科现存各属均为古老的孑遗或残遗类群。     

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。     

从核型看北美红杉的起源

本文分析了同源异源自然六倍体北美红杉的AA和B染色体组的组型,它们属Stebbins的“1A”和“1B”,经与杉科各属植物的核型比较后发现分别与相同类型的水杉和巨杉最为接近,因而认为水杉属和巨杉属的某个古代种可能是北美红杉的二个杂交亲本,水杉和巨杉则或许是它们的后裔或近缘。本研究支持Stebbins认为水杉属的某个古代种是红杉的一个祖先而水杉是它的直接后裔的假设,但与他认为另一个祖先已经灭绝并没有留下近缘的推测存在分歧。     

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。     

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。     

江西产酸模属植物叶片比较解剖学研究

对江西产酸模属(Rumex L.)7种植物进行了叶形态结构的显微观察.结果表明:(1)叶片上表皮均有气孔器分布,表皮上普遍具有腺体和异细胞,叶肉中均含有晶体细胞,晶体类型为簇晶;(2)下表皮细胞特征及气孔类型、叶肉细胞的分化及排列方式、中脉维管束数目等特征具有明显的种间差异,可以作为属下种级鉴定指标;(3)小酸模在气孔类型、栅栏组织和海绵组织排列紧密程度、中脉形状及维管束数量等特征上与同属其它种类具有显著的差异,形态解剖学证据支持小酸模亚属(Subgen.Acetosella(Meisn.)Rech.)的成立;(4)根据酸模属植物气孔器类型的演化阶段,并结合孢粉学、形态学等证据,认为酸模属处于蓼科植物系统演化的较低或中等地位.通过对酸模属植物叶形态结构的比较观察,为探讨该属的系统演化关系及属下分类提供叶解剖学证据.     

水杉是北美红杉的一个亲本吗？

本文根据有关细胞学和形态学资料.不同意Schlarbaum等以红杉没有水杉的具长着丝点区域的标记染色体来否定水杉(属)是红杉的亲本,同时认为,他们提出某种杉木属植物为红杉提供了染色体组而是它的亲本的意见难以成立,从而支持Stebbins的假设,水杉(属)可能是北美红杉的一个亲本。而且,它或许还是一个父本。     

5种石杉属植物叶表皮特征研究

利用光学显微镜及电子显微镜对石杉科(Huperziaceae)石杉属(Huperzia)5种植物:蛇足石杉(Huperzia serrata(Thunb.ex Murray)Trev.)、皱边石杉(Huperzia crispata(Ching)Ching.)、四川石杉(Huperzia sutchueniana(Herter)Ching.)、南岭石杉(Huperzia nanlingensis)和长柄石杉(Huperzia javaensis)的叶片微结构进行观察与研究。结果显示:这5种石杉均无叶表面附属物,具无规则四细胞型和不规则型两种类型的气孔,不规则型为主要气孔类型。这5种石杉在气孔组成上具多型现象,气孔多为下生型,分布方式及大小多样;叶表皮细胞在不同类型中有大小差异但均呈不规则状,表皮细胞垂周壁呈波纹状(深波状、浅波状)。上述研究结果为石杉属植物的进一步分类与研究提供依据。     

从形态学看北美红杉的亲本

本文通过形态性状的比较研究认为AAAABB的同源异源多倍体红杉可能由亲本水杉(属)和巨杉(属)杂交起源,它们分别为红杉提供了染色体组AA和染色体组B。这与根据核型等资料的分析结果相吻合。但跟Stebbins认为红杉除水杉(属)以外的另一个亲本已经灭绝并没有留下近缘的推论存在分歧。     

水杉的核型研究

本文观察了水杉的染色体,确定2n=22,核型公式为K(2n)=22m(2SAT),全具中着丝点,有一对随体。第8、10、11号染色体具“长着丝点区域”。属“1A”型,与北美红杉-AA的核型非常相近,可能是它的一个亲本种的直接后裔。     

Atrial natriuretic-like peptide and its prohormone within metasequoia.

Metasequoia glyptostroboides was one of the dominant conifers in North America, Asia, and Europe for more than 100 million years since the late Cretaceous Albian Age, but Quaternary glaciations drove the Metasequoia population to apparent extinction. A small pocket of Metasequoia, however, was found in central China in the 1940s representing the only surviving population of this "living fossil" species. Atrial natriuretic peptide, a 28-amino-acid peptide hormone that causes sodium and water excretion in animals, has been found to be part of the first peptide hormonal system in lower plants. The existence of this hormonal system has never been examined within trees of any genus. High-performance gel permeation chromatography of the leaves and stems (i.e., branches) of Metasequoia followed by atrial natriuretic peptide radioimmunoassay revealed an ANP-like peptide and its prohormone (i.e., approximately 13,000 mol wt) were present in both leaves and stems of this conifer. The elution profile of ANP-like peptide in stems of Metasequoia had a shoulder to the left of where pure synthetic ANP elutes suggesting the possibility of a slightly larger peptide eluting within this shoulder secondary to alternate processing of the ANP-like prohormone and similar to what occurs with the kidney of animals. The elution profile of ANP-like peptide in the leaves of Metasequoia revealed two peaks; one where ANP elutes and a second peak suggesting a smaller peptide that has been metabolically processed. The presence of the ANP-like prohormone strongly suggests that ANP-like gene expression is occurring in both leaves and stems of Metasequoia since this prohormone is the gene product of this hormonal system. The presence of the ANP-like hormonal system in trees implies that this hormonal system may have been present early in land plant evolution to allow trees to reach heights of greater than 30 feet where a water flow-enhancing substance is absolutely necessary for water flow to occur to these heights.     

红杉属植物在中国云南中新世首次发现

化石标本采自中国云南省中部楚雄市吕合煤矿的石鼓村层 ,该层为灰色至浅灰色细砂岩至粗砂岩、粉砂质粘土层和褐煤层 ,地质时代属中新世 ① 。石鼓村层的孢粉组合以被子植物占绝对优势(90 % ) ,其中热带、亚热带植物成分类型较多 ,如金缕梅科、棕榈科等 ,温带植物成分类型较少 ,如榆科、桦木科等 ;裸子植物花粉占整个孢粉组合的 9% ,主要是松科和杉科花粉 ;蕨类植物孢子仅占整个孢粉组合的 1% ,以水龙骨单缝孢为主。本次发现的标本小枝长约 2 .8ｃｍ ,宽约 1.6ｃｍ ,小枝基部稍膨大。叶螺旋状排列 ,基部扭转 ,在同一平面排成 2列 ,以 30～ 70…     

杉科、柏科的系统发生分析——来自28S rDNA序列分析的证据

对杉科（Taxodiaceae）与柏科（Cupressaceae s.s.）的28S rRNA基因的部分序列（约630 bp）进行PCR扩增、序列测定和系统发生关系分析,用简约法和邻接法构建的系统发生树基本一致。结果表明,杉科与柏科构成一个单系群,支持将杉科、柏科（Sciadopitys除外）合并为一个科——广义柏科（Cupressaceae sensu lato）的观点。在广义柏科中,Taiwania、Athrotaxis分别形成一支系;Metasequoia、Sequoia、Sequoiadendron关系较近,聚成一支系; Taxodium、Glyptostrobus、Cryptomeria聚成一支系;柏科聚成一支系。这一分析结果与叶绿体基因序列的分析结果相吻合,但是由于28S rRNA基因的进化速率较慢,尚不能分辨上述各个支系之间的系统演化关系。 Abstract:DNA sequences from 28S rDNA were used to assess relationships between and within traditional Taxodiaceae and Cupressaceae s.s.The MP tree and NJ tree generally are similar to one another.The results show that Taxodiaceae and Cupressaceae s.s.form a monophyletic conifer lineage excluding Sciadopitys.In the Taxodiaceae-Cupressaceae s.s.monophyletic group,the Taxodiaceae is paraphyletic.Taxodium,Glyptostrobus and Cryptomeria forming a clade(Taxodioideae),in which Glyptostrobus and Taxodium are closely related and sister to Cryptomeria;Sequoia,Sequoiadendron and Metasequoia are closely related to each other,forming another clade (Sequoioideae),in which Sequoia and Sequoiadendron are closely related and sister to Metasequoia;the seven genera of Cupressaceae s.s.are found to be closely related to form a monophyletic lineage (Cupressoideae).These results are basically similar to analyses from chloroplast gene data.But the relationships among Taiwania,Sequoioideae,Taxodioideae,and Cupressoideae remain unclear because of the slow evolution rate of 28S rDNA,which might best be answered by sequencing more rapidly evolving nuclear genes.     

On the Ultrastructure of Pollen Exine in Metasequoia Hu and Cheng

Metasequoia is endemic to China. Present study deals with ultrastructure of pollen exine of M. glyptostroboides Hu et Cheng, and in comparision with other genera of the family. Pollen grains of Metasequoia are spheroidal or subsphoroidal and 27.8(24.3–32.3) μm in diameter. There is a papilla in the distal face. The papilla is wide at the base, 3.5–5.2 μm high, with pointed and circular end and the base crooked toward one side. Exine is about L5 μm thick, layers distinct, Nexine is as thick as sexine. Surface weakly granulate. According to observation by SEM, exine is covered with fine granules and rather coarse tuberculae. The former can be easily separated from the latter. The loose and uneven tuberculae are provided with minute spinules on the surface and generally fall off after acetolysis. The fine and dense granulae, however, remain intact after acetolysis. The study by TEM shows that ektexine is made of granules densely arranged and connected with each other. In addition, sparse Ubisch bodies are unevenly distributed on granular layer with geminate surface. The thick endexine, is composed of 10–15 lamellae. It is worthy to note that all lamellae possess tripartite structure. But lamellae of endexine in other genera of Taxodiaceae have no tripartite structure except the lamella near ektexine. Number of lamella and thickness of endexine in Metasequoia differ from those of other genera in Taxodiaceae; for example endexine with 8–10 lamellae in Taxodium, 8–9 lamellae in Sequoia, 6–7 lamellae in Glyptostrobus, 6–8 lamellae in Cunninghamia, about 16 lamellae in Cryptomeria etc.     

On Metasequoia in Eocene Age from Liaoning Province of Northeast China

The fossil specimens of Metasequoia Miki, aged in early Eocene was collected from Guchengzi and Jijuntun Formations of Fushun, Liaoning Province, Northeast China. Female and male cones and nutricious shoots, together with leafy epidermis and epidermis of staminal bract were investigated and here by described in details. The specimens is attributed to M. occidentalis after comparing them with M. glyptostroboides, M. milleri and M. occidentalis, considering the characteristics of leaves, female and male cones, epidermal cells and stomata. The average stomatal density of M. glyptostroboides in the stomatal distributional regions is measured to be 183.85/mm2, that of Fushun specimens 140.13/mm2; the average stomatal index of M. glyptostroboides in the stomatal distributional regions is 10.79, that of Fushun specimens is 9.48.     

中国辽宁省始新世水杉的研究

以辽宁省抚顺早始新世古城子组和计军屯组的水杉（Ｍｅｔａｓｅｑｕｏｉａ Ｍｉｋｉ）为研究对象,对其雌球果、雄球花枝和营养枝叶的形态、叶表皮和雄球花苞片表皮的结构进行了研究分析,并与Ｍ．ｇｌｙｐｔｏｓｔｒｏｂｏｉｄｅｓ,Ｍ．ｏｃｃｉｄｅｎｔａｌｉｓ,Ｍ．ｍｉｌｌｅｒｉ的性状进行比较,认定其属于Ｍ．ｏｃｃｉｄｅｎｔａｌｉｓ。并没得Ｍ．ｇｌｙｐｔｏｓｔｒｏｂｏｉｄｅｓ和抚顺水杉叶下表皮气孔分布区内的平均气