保护植物进化的“足迹”

中生代的苏铁,几乎遍布整个地球,在当时,地球上每三种植物中就有一种是苏铁类植物,堪称中生代植物界的一大旺族。然而盛极而衰,曾经繁荣显赫的苏铁类家族在历经沧海桑田后,目前仅留存少数后裔,也就是我们通常所提及的苏铁科、蕨铁科和泽米铁科植物,共计3科、11属,约300种植物.     

4种耐风沙盐碱植物导管分子的比较解剖学研究

利用导管分子离析及光学显微技术,对榆属3种植物与胡颊子属植物沙枣次生木质部导管分子进行了比较结构学研究.结果表明:栓皮眷榆、蒙古黄榆、白榆和沙枣离析导管分子在风沙盐碱的恶劣环境下演化出不同的形态和各自的适应性.榆属3种植物导管分子侧壁均为螺纹加厚,纹孔为对列-互列型,但导管分子平均长度和平均直径呈反比.沙枣导管分子侧壁为全面加厚,纹孔为进化的孔纹,直径远大于榆属3种植物.分析表明,沙枣最适宜沙地种植,可用来做绿化树种.     

5种蕨类植物木质部管状分子的研究

为研究蕨类植物木质部管状分子的类型及特点,分别对蕨(Pteridium aquilinum var. latiusculum)、银粉背蕨(Aleuritopteris argentea)、华北薄鳞蕨(Leptolepidium kuhnii)、荚果蕨(Matteuccia struthiopteris)和耳叶金毛裸蕨(Gymnopteris bipinnata var. auriculata) 5种蕨类的叶柄或根状茎维管束进行离析处理,并在光学显微镜和扫描电镜下观察和照相.结果显示: 1)5种蕨类植物中都有导管分子存在,耳叶金毛裸蕨除具有导管分子外,还有管胞; 2)导管分子普遍具有多穿孔板,穿孔板以梯状为主,偶有网状,但没有单穿孔板,各种蕨类的管状分子中都存在不同程度的纹孔膜残余; 3)蕨导管分子的端壁和侧壁分化明显,存在网状穿孔板,并具有纹孔二型性现象,以及多孔性纹孔膜和凹槽结构; 4)银粉背蕨叶柄导管分子的穿孔板有的与纹孔膜完整的壁相邻,根状茎导管分子的侧壁之间以"脊"状结构相隔; 5)华北薄鳞蕨叶柄导管分子中存在不连续穿孔板,根状茎管状分子的端壁和侧壁分化鲜明; 6)荚果蕨叶柄导管分子中存在网状-梯状混合型穿孔板; 7)耳叶金毛裸蕨叶柄中同时具有导管分子和管胞,导管分子的穿孔板有的与纹孔膜完整的壁相邻; 8)与被子植物相比,蕨类植物导管分子的特征在很大程度上体现了其原始性.     

植物界的大熊猫——苏铁

1999年11月,中国科学院华南植物研究所和华南农业大学的联合调查组对深圳塘朗山进行生物多样性本底资源调查,期间意外地发现了仙湖苏铁的野生种群。仙湖苏铁(Cycasfairylakea)为苏铁科、苏铁属、攀枝花苏铁组植物,是我国20多种苏铁中的一种,也是我国的特有种,目前仅在深圳和广西发现有分布。苏铁的变迁苏铁号称恐龙时代的“活化石”,是现存种子植物中最原始的类群,极具科研价值。苏铁历史悠久,早在2.5亿年前的古生代二迭纪即已出现,于中生代的侏罗纪繁荣旺盛。苏铁类作为恐龙的主要食物,与恐龙共同成为1.6—1.9亿年前地球上占统治地位的生…     

苏铁在种子植物进化中的位置：分子生物学的证据

用大分子rRNA快速测序法测定了苏铁(Cycas revoluta Thunb.)、水松[Glyptos-trobus pensilis(Staunt.)Koch]和南方红豆杉[Taxus mairei(Lemee et Levl)S.Y.Hu]三种裸子植物Ls-rRNA5′端区108个核苷酸的序列。用这些数据构建的rRNA系统树揭示了苏铁与水松和南方红豆杉构成一个关系密切的姐妹群,而所分析的被子植物都为另一自然类群。另以绿藻作为种子植物群外参照物种,表明苏铁这一位置并不是由于一个特异的进化速度所造成的。这一结果支持了苏铁与松杉类为一自然群类,它们的分歧发生在裸子植物与被子植物分歧之后的假说。     

蔷薇科9属12种代表植物导管类型的解剖学观察

初步研究了蔷薇科Rosaceae 9属12种代表植物的导管类型、数量及导管分子的长度、口径;纤维分子的长度、口径。结果表明：较进化的种类一般都是孔纹导管和网纹导管,较原始的种类一般都是环纹和螺纹导管;导管分子长度长的则导管口径小,导管分子长度短的则口径大;纤维分子长度普遍大于导管分子长度,而纤维分子的口径也普遍小于导管分子的口径。     

应用树脂铸型法研究木质部导管的内部结构

将树脂铸型法（ｒｅｓｉｎ ｃａｓｔｉｎｇ ｍｅｔｈｏｄ）用于藤本和灌木共五种植物导管的内部结构研究。干燥的小木块用苯乙烯包埋,完全聚合后,用过氧化氢／冰醋酸（１：１）溶液和浓硫酸溶液交替处理,完全去除细胞壁成分,得到的导管树脂铸型在扫描电子显微镜下观察,能清晰,精确的反映出纹孔道,纹孔室,螺纹加厚,导管分子端壁及尾等三维立体结构特征。     

试论单子叶植物的原始类群

本文从被子植物系统分类理论观点出发,结合植物分子系统学的最新研究成果,综合分析和讨论了单子叶植物的原始类群,结果认为,单子叶植物是一个单元起源的自然类群,其原始类群具有单沟型花粉,离生心皮,草本或半草本,陆生等特征,泽泻目（Alismatales)是现存单子叶植物中具备较多原始特征的类群。     

鸢尾蒜营养器官的解剖学研究

观察表明：鸢尾蒜（Ｉｘｉｏｌｉｒｉｏｎｔａｔａｒｉｃｕｍ）营养器官的结构具有单子叶植物的基本结构特征，并有一些特殊和原始的结构特征，以及早生结构特征。根内原生木质部３～５原型；内皮层有凯氏点，这在单子叶植物中很少见。茎皮层内有５～７层厚壁细胞组成的纤维带；维管束大致排成２轮，内轮较大。叶表皮气孔器由２个肾形保卫细胞组成；叶肉上下有分化，上方栅栏状，下方紧密，成异面叶。茎叶木质部的发育方式原始，为外始式，这一特殊结构在被子植物中未见有报道。     

苏铁的害虫——美丽的曲纹紫灰蝶

苏铁是最原始的种子植物之一,国家一级保护树种。其树形古朴高雅,主干粗壮,坚硬如铁,叶锐如针,洁滑光亮,四季常青,是一类盆栽或庭园观赏植物,具有重要的经济价值。但科学家在苏铁上发现了以往罕见的食叶害虫,经饲养后,育出美丽的蝴蝶——曲纹紫灰蝶。近十多年来,曲纹紫灰蝶由偶     

Identification of diploid endosperm in an early angiosperm lineage

In flowering plants, the developmental and genetic basis for the establishment of an embryo-nourishing tissue differs from all other lineages of seed plants. Among extant nonflowering seed plants (conifers, cycads, Ginkgo, Gnetales), a maternally derived haploid tissue (female gametophyte) is responsible for the acquisition of nutrients from the maternal diploid plant, and the ultimate provisioning of the embryo. In flowering plants, a second fertilization event, contemporaneous with the fusion of sperm and egg to yield a zygote, initiates a genetically biparental and typically triploid embryo-nourishing tissue called endosperm. For over a century, triploid biparental endosperm has been viewed as the ancestral condition in extant flowering plants. Here we report diploid biparental endosperm in Nuphar polysepalum, a basal angiosperm. We show that diploid endosperms are common among early angiosperm lineages and may represent the ancestral condition among flowering plants. If diploid endosperm is plesiomorphic, the triploid endosperms of the vast majority of flowering plants must have evolved from a diploid condition through the developmental modification of the unique fertilization process that initiates endosperm.     

银杏雌配子体形成及颈卵器发育的细胞学研究

银杏的功能大孢子经１０多次游离核分裂,形成约２０００个核后,向心地形成细胞壁。雌配子体中游离核之间细胞壁还未完全形成时,在其近珠孔端表面可看到颈卵器线细胞发生。一个雌配子体中的颈卵器数目通常为２个,它们的发育最初不同步,以后逐渐趋向一致,在颈卵器的发育过程中的颈卵器颈细胞和中央细胞的形态及结构都发生了较大的变化。颈卵器的２个颈细胞的受精前进行一次斜向分裂形成４个颈细胞,此分裂一般早于中央细胞的分裂     

Independent recruitment of a conserved developmental mechanism during leaf evolution

Vascular plants evolved in the Middle to Late Silurian period, about 420 million years ago. The fossil record indicates that these primitive plants had branched stems with sporangia but no leaves. Leaf-like lateral outgrowths subsequently evolved on at least two independent occasions. In extant plants, these events are represented by microphyllous leaves in lycophytes (clubmosses, spikemosses and quillworts) and megaphyllous leaves in euphyllophytes (ferns, gymnosperms and angiosperms). Our current understanding of how leaves develop is restricted to processes that operate during megaphyll formation. Because microphylls and megaphylls evolved independently, different mechanisms might be required for leaf formation. Here we show that this is not so. Gene expression data from a microphyllous lycophyte, phylogenetic analyses, and a cross-species complementation experiment all show that a common developmental mechanism can underpin both microphyll and megaphyll formation. We propose that this mechanism might have operated originally in the context of primitive plant apices to facilitate bifurcation. Recruitment of this pathway to form leaves occurred independently and in parallel in different plant lineages.     

3种入侵杂草次生木质部的细胞结构

运用离析法和显微照相等技术,比较了黄顶菊、豚草、加拿大一枝黄花3种入侵植物茎和根中次生木质部细胞的特征。结果表明,3种入侵植物根、茎的次生木质部中孔纹和网纹导管分子较多,具多尾性,单穿孔板,少数导管分子还具侵填体等特征,这都在一定程度上说明3种植物在系统进化中占有较高的地位。同一种植物中茎的导管分子平均长度长于根中,平均宽度宽于根中,且均达极显著差异;同一种植物的茎中和根中导管分子的长度、宽度并不一定有一致性。管胞细胞、纤维细胞的平均长度和宽度在3种植物间均未表现出一定的规律性。这些现象都说明植物为了更好的适应不同的生活环境而形成了一定的结构。     

Jurastrobus chenii gen. et sp. nov., a cycadalean pollen cone connected with vegetative parts from Inner Mongolia, China

Cycads used to be a dominant plant group during the Mesozoic. Many fossils of cycads or their allies have been documented, but most of them are foliages. Reproductive organs are scarce and mostly found detached from vegetative organs. Among cycad reproductive parts, ovulate cones are rather frequently seen in the fossil record, while pollen cones are rare. Here we report a cycadalean pollen cone connected with its vegetative parts from the lower Jurassic of Inner Mongolia, China. The pollen cone is situated on the apex of the stem and in the center of the leaf tuft. The pinnate leaves have lateral pinnae attached decurrently and almost perpendicularly to the rachis. The characters demonstrate a strong affinity to the extant cycads. This is the first record of cycadalean pollen cone with in situ pollen grain and organically connected with its vegetative parts, and therefore sheds new light on the morphological evolution of cycad plants.     

Jurastrobus chenii gen. et sp. nov., a cycadalean pollen cone connected with vegetative parts from Inner Mongolia, China

Cycads used to be a dominant plant group during the Mesozoic. Many fossils of cycads or their allies have been documented, but most of them are foliages. Reproductive organs are scarce and mostly found detached from vegetative organs. Among cycad reproductive parts, ovulate cones are rather frequently seen in the fossil record, while pollen cones are rare. Here we report a cycadalean pollen cone connected with its vegetative parts from the lower Jurassic of Inner Mongolia, China. The pollen cone is situated on the apex of the stem and in the center of the leaf tuft. The pinnate leaves have lateral pinnae attached decurrently and almost perpendicularly to the rachis. The characters demonstrate a strong affinity to the extant cycads. This is the first record of cycadalean pollen cone with in situ pollen grain and organically connected with its vegetative parts, and therefore sheds new light on the morphological evolution of cycad plants.     

石漫滩国家森林公园药用植物资源调查与研究

通过实地调查、采集标本、数码照相、分类鉴定和查阅文献相结合的方法,对河南石漫滩国家森林公园药用植物资源状况进行了较为系统的调查.结果发现,该区域药用植物有87科,266种,其中蕨类植物7科,7种;裸子植物3科,4种;种子植物77科,255种.对该区域重要的药用植物种类进行了药效分析.针对目前人们对药用植物盲目无序采挖和资源日渐匮乏的现状,提出了野生药用植物资源的保护与开发利用的建议.     

After a dozen years of progress the origin of angiosperms is still a great mystery

Here we discuss recent advances surrounding the origin of angiosperms. Putatively primitive characters are now much better understood because of a vastly improved understanding of angiosperm phylogenetics, and recent discoveries of fossil flowers have provided an increasingly detailed picture of early diversity in the angiosperms. The 'anthophyte theory', the dominant concept of the 1980s and 1990s, has been eclipsed; Gnetales, previously thought to be closest to the angiosperms, are related instead to other extant gymnosperms, probably most closely to conifers. Finally, new theories of flower origins have been proposed based on gene function, duplication and loss, as well as on morphology. Further studies of genetic mechanisms that control reproductive development in seed plants provide a most promising avenue for further research, including tests of these recent theories. Identification of fossils with morphologies that convincingly place them close to angiosperms could still revolutionize understanding of angiosperm origins.     

四川百里峡省级自然保护区植物资源调查研究

为进一步掌握四川百里峡省级自然保护区植物资源的现状,对保护区植物资源进行调查,结果表明:自然保护区共有野生维管植物150科,682属,1 429种.其中蕨类植物22科,44属,74种;裸子植物8科,17属,24种;被子植物120科,625属,1 319种.维管植物科数占四川省的64.66%,全国的41.21%;属数占四川省的42.32%,全国的20.20%;种数占四川省的15.32%,全国的4.88%.保护区有国家Ⅰ级保护植物7种,国家Ⅱ级保护植物13种,此外还有现被列为世界级极危植物—崖柏.种子植物区系共有15个类型和18个变型.植物区系温带性质明显,热带成分也占一定的比例,具有温带向热带过渡的特征.植物区系具有一定的古老性.保护区植被划分为3个植被型组,8个植被型,24个群系.     

连通容器甲烷-空气混合物抑爆影响因素

为了研究连通器甲烷-空气混合物抑爆的影响因素,利用小球容器、管道、大球容器建立了5种结构的连通容器气体爆炸测试系统,在40目丝网结构条件下,研究了管道长度、丝网层数、传爆容器、抑爆位置等对连通容器甲烷-空气混合物爆炸强度的影响。结果表明:小球容器与管道连通时,随着丝网层数和接管长度的增加,管道末端的压力逐渐降低;当增加传爆容器时,球形容器与管道内气体爆炸强度增加;小球容器与1段管道以及大球容器连通时,丝网层数越多,抑爆效果越明显;小球容器与2段管道以及大球容器连通时,丝网结构能够产生一定的抑爆效果,但抑爆效果不明显;小球容器与3段管道连通时,抑爆位置对连通容器抑爆效果产生较大影响。抑爆位置对连通容器抑爆效果与丝网结构的层数有关。因此,在实际生产应用中,应综合考虑多种因素的影响,以达到最佳的抑爆效果。