太白山北坡光资源斑块与独叶草种群分布的耦合关系

独叶草(Kingdonia uniflora)是我国稀有濒危植物,在其分布区内呈斑块状分布。本研究采用数字影像技术、地理信息系统和数字冠层分析系统对太白山北坡独叶草分布地段林下光资源斑块、林冠结构特征、土壤理化性质进行了分析。结果显示:有独叶草分布的样方中光斑数量、光斑面积及光斑指数值均显著低于无独叶草分布的样方;有、无独叶草样方上层林冠结构差异显著,有独叶草分布地段的冠层散射透过系数、直射透过系数和林冠空隙面积均显著小于无独叶草分布地段,而叶面积指数与之相反;两类样方土壤理化性质均无显著差异。因此,推测在太白山北坡林下光斑可能是决定独叶草斑块状分布的主导因子之一。     

星叶草属的核形态及其系统位置

本文研究了星叶草属的核形态。其间期核和前期染色体分别为简单染色中心型和中间型;中期染色体较小,长度介于3.00μm到1.20μm之间;核型公式为2n=30=22m+8sm。其明显很高的染色体基数以及其它退化和特化的形态学性状,表明该属是一个孑遗的古多倍体类群。该属与独叶草属在间期核形态、前期染色体形态以及中期染色体的大小和形态方面极为相似。结合其它方面的资料,本文认为星叶草属和独叶草属有较近的亲缘关系,支持将它们一起置于星叶草科的观点。     

独叶草营养繁殖方式的研究

对独叶草营养繁殖中根状茎的生长和分枝方式及克隆植株产生方式的研究表明 :( 1 )独叶草的根状茎的生长方式为游击型的 ,新分枝可由顶芽或侧芽产生 ,各分枝与上一级的夹角在 50°～ 1 2 0°之间 ;( 2 )独叶草是通过根状茎断裂的方式来增加克隆植株的 ,这种断裂发生在 3年以上生的根状茎上 ,从内部结构上看 ,根状茎断裂是由于组织破碎引起的。     

基于MaxEnt濒危植物独叶草的中国潜在适生分布区预测

独叶草(Kingdonia uniflora Balf.f.et W.W.Smith)属毛茛科独叶草属多年生草本植物,属国家二级濒危保护植物。近年来,随着森林采伐和人类活动加剧生境的破碎化,独叶草自然分布区迅速缩减,存在濒临灭绝的风险。预测独叶草潜在的适宜分布区,对于合理保护和利用独叶草具有重要意义。本文结合64份独叶草的标本地理信息和14个环境因子参数,应用最大熵模型(Max Ent)和地理信息技术(GIS),对独叶草在中国的潜在适生分布区和影响分布的关键环境因子进行了预测。受试者工作特性曲线(ROC)分析法的AUC值为0.990,表明Max Ent模型预测可靠性极高。预测结果显示,独叶草最适潜在分布区主要在陕西秦岭北坡(眉县,太白县)、四川省的邛崃山(理县,马尔康县)和大凉山(马边彝族自治县),云南东北部和贵州西北部交界的大娄山(金沙县)和乌蒙山(赫章县)部分地区(适生指数0.5)。刀切法检测(Jackknife test)分析表明,影响独叶草适生分布的关键环境因子包括年均降水量(贡献率33.1%)、海拔(22.3%)、温度季节性变化的标准差(11.4%)、降水量变异系数(7.2%)、土壤p H(5.4%)、1月最低温(5.1%)和土壤碎石百分比(4.9%)。适生区环境参数综合统计分析表明,独叶草最适宜生长在高海拔(1646~2810 m)、年均降水量大(856 mm)、1月最低温适中(-7.2℃)和土壤偏酸性(p H 6.89)的地区。上述研究结果将为在最适生区通过合理规划自然保护区来保护独叶草野生资源提供理论依据。     

太白山独叶草无性系分株营养元素含量对异质环境的响应

以分布在太白山国家森林公园3个海拔高度的游击型克隆植物独叶草为研究对象,分析测定了不同分株营养器官中C、N、P、K和Mg含量.结果表明：分株年龄、海拔梯度以及分株年龄与海拔梯度的交互作用对独叶草分株各营养器官全碳含量的影响不显著(P>0.05),对全氮、全磷、K和Mg含量的影响程度各不相同,说明独叶草无性系分株通过自身的生理代谢调整了各器官中营养元素的分配.在高海拔生境中,分株年龄显著影响独叶草无性系分株各器官的K含量、根状茎和根中的全氮含量(P<0.05).除了中海拔(2 800～2 900 m) 独叶草无性系分株的K与全氮、全磷和Mg含量相关性不明显外,其他海拔各元素两两间均呈显著相关(P<0.05).这表明高海拔生境中生理可塑性对克隆植物生长的贡献可能比低海拔更大,强的生理可塑性有助于克隆植物在高山环境中有效地利用资源,实现种群扩展、开拓新的生境.这也可能是独叶草在长期演化过程中对异质生境的一种生理响应.     

独叶草叶片性状表型多样性研究

独叶草是特产于中国的一种珍稀濒危植物.为研究独叶草自然居群的叶片形态变异特征及影响因素,选取分布于陕西、四川、甘肃的9个自然居群,对独叶草叶片的叶面积、叶柄长、总齿数、末级叶脉数、盲脉数、网结脉数等指标进行统计分析.结果表明:(1)独叶草叶片各属性间存在显著相关性,个别性状表现出与地理位置的相关性.(2)主成分分析显示独叶草的末级叶脉数、叶面积、总齿数对变异有较大贡献,而网结脉贡献很小.(3)独叶草叶片性状居群间变异程度大于居群内,其中盲脉数量在各个居群间变异程度最大,而末级叶脉数为最稳定的性状.(4)将本研究中形态变异结果与前期的遗传分析结果对比分析认为独叶草形态变异主要来自生态环境,而非遗传组成.(5)独叶草居群的形态及遗传变异聚类结果都显示独叶草形态变异并不具有地理格局规律,可能由于地质历史变化打断了独叶草原本连续的分布区,遗传保守性使其仍然保持分布区断裂前的遗传特性,但其表型随着生境的变化表现出可塑性.     

独叶草形态学研究 II．根状茎的解剖

本文为独叶草形态学研究的一部分,主要报道其根状茎结构的初步观察结果。根状茎的初 生结构的基本图案类似一般多年生草本植物的根状茎。但其维管束连接成简状,缺乏髓射线, 以后产生的次生维管组织中亦缺乏明显的射线。木质部的导管主要为梯纹加厚。梯纹导管的分 子的穿孔板呈水平的和不同程度的倾斜状的,水平的和一部分倾斜状的穿孔板上只具有单个 大穿孔,而另一些倾斜状的穿孔板上,呈一种复穿孔到单穿孔的过渡形式。参照Bailey(1956) 指出的管状分子的演化是不可逆的观点,联系到毛茛科植物一般具有单穿孔的导管,应属于一种原始的结构特征。独叶草的营养叶,鳞片叶和芽苞叶都具有单叶隙,前者具四个叶迹,后两 者都具有一个双重性的叶迹。参照前人的看法,联系独叶草的叶,花和导管分子中的一些原始性状推测,可能如Foster(1960,1961)曾指出的,在三叶隙和多叶隙占多数的毛莨科中,独叶草的单叶隙可能是一种原始的形态。     

江浙獐牙菜的小孢子发生和雄配子体形成及其系统学意义

采用常规石蜡切片技术,对江浙獐牙菜(Swertia hickinii Burk)花药壁形成、小孢子发生和雄配子体形成过程进行了研究。结果表明:(1)花药四室,花药壁由表皮、药室内壁、中层和绒毡层组成,药壁发育为双子叶型。绒毡层异型起源,腺质型。花粉成熟时药室内壁径向加长并纤维状加厚,表皮宿存。(2)小孢子母细胞在减数分裂过程中胞质分裂为同时型;小孢子四分体排列方式主要为四面体型,也有左右对称型和"T"型等其他类型;成熟花粉为3-细胞型,具三萌发沟。另外,对獐牙菜属的雄性胚胎学特征进行了全面总结,并与龙胆属、蔓龙胆属及双蝴蝶属进行比较归纳出其共性。研究认为,花药表皮宿存或退化,是獐牙菜属与双蝴蝶属的重要区别之一。     

川东獐牙菜(龙胆科)的胚胎学研究

利用石蜡切片技术,对川东獐牙菜(Swertia davidii)的胚胎发育过程进行显微观察,并根据现有资料,对獐牙菜属的几种植物进行了比较胚胎学研究。结果表明:川东獐牙菜花药四室,药壁发育为基本型,绒毡层异型起源,为腺质绒毡层,发育后期药室内观察到的绒毡层核是早期该层细胞有丝分裂凸入药室并原位退化形成的,中层细胞3层,药室内壁退化,花药壁表皮宿存,细胞柱状伸长,纤维状加厚;小孢母细胞减数分裂为同时型,四分体排列方式主要为四面体形和左右对称型,少数为"T"形和十字交叉形,成熟花粉为2-细胞类型;子房2心皮、1室,侧膜胎座;薄珠心,单珠被,倒弯生胚珠,大孢子母细胞减数分裂形成4个大孢子直线形排列,合点端的大孢子具功能,雄配子体发育为蓼型;2个极核在受精前融合为1次生核,合点端3个反足细胞宿存,每个细胞均多核和异常膨大,形成明显的反足吸器,并在胚乳之外形成染色较深的类似"外胚乳"结构;珠孔受精,受精作用属于有丝分裂前类型;胚乳发育为核型,胚胎发育为茄型;果实成熟时,种子发育至心形胚阶段;反足细胞在龙胆科一些短命植物中的宿存与分裂具有重要的生殖适应与进化意义。     

喉毛花的胚胎学研究

本文首次系统地记载了喉毛花属的胚胎发育过程,并以此为依据讨论了该属的分类等级和系统位置。喉毛花花药四室;药壁发育属双子叶型;绒毡层单型起源,细胞具单核,属腺质绒毡层;一层中层细胞;花药壁表皮层宿存,纤维状加厚和膨大;药室内壁减缩。小孢子母细胞减数分裂为同时型,四分体的排列为四面体型;成熟花粉为3-细胞型。子房为2心皮、l室,典型的侧膜胎座,胚珠8列,胚珠胎座靠近两心皮腹缝线。薄珠心,单珠被,倒生胚珠。大孢子母细胞减数分裂形成的4个大孢子呈直列式排列,其中合点端的大孢子具功能。胚囊发育为蓼型。极核在受精前融合为次生核。反足细胞宿存、分裂为8～12个,每个细胞均多核和异常膨大,反足细胞形成的吸器明显。异花传粉,珠孔受精。花粉管通过破坏一助细胞进入胚囊。受精作用属于有丝分裂前配子体融合类型。胚乳发育为核型,每核含2～3核仁。胚胎发育为茄型酸浆I变型,成熟种子胚只发育至球形胚阶段。反足细胞在合子分裂之后才开始退化,在胚的发育过程中反足细胞在胚乳层之外形成一层染色深、类似“外胚乳”的结构。比较喉毛花、龙胆属、假龙胆属以及肋柱花属的胚胎学特征表明喉毛花与假龙胆属的亲缘关系最近,在分类等级上作为一个独立的属较为合适,在系统位置上它比假龙胆属更为原始。     

Kingdonia,Embryology and Its Systematic Significance

The embryological studies show that Kingdonia is similar to Circaeaster while different from other members of the Ranunculales (sensu Takhtajan, 1980) in development of endosperm and embryo. We consider that there is close systematic relationship between Kingdonia and Circaeaster.     

独叶草的根和节部及叶的解剖学研究

报道了独叶草根、节部和叶的剖解学特征。这些器官在解剖学上表现出的突出点是：根具２个以上的根毛区（与星叶草机相同）,中有少量的次生生长,皮层细胞中具内生真菌;变态叶的叶迹或为单迹单维管组织束,或为单迹２维管组织束,或２迹在向皮层外部延伸过程中合并为具２条维管组织束的单迹;叶柄维管束不存在厚壁的维管束鞘,且在由基部向顶部延伸的过程中常发生复杂的分枝及汇合;叶片具有同形的叶肉植物,叶脉维管束鞘具２层细胞     

基于形态学资料星叶草属系统位置的探讨

基于以往的形态学研究资料,对星叶草属与毛茛目其它成员进行了比较。结果表明,该属在一些基本的或原始的性状上与其它毛茛目成员相似,特别是它与毛茛科一些植物幼苗问的相似性表明,这个属应该属于毛茛目的成员,而且有可能通过幼态成熟的方式起源于前毛茛目植物。星叶草属与其它毛茛目成员问的区别,尤其是在维管系统和胚胎发育方面的区别表明,星叶草属在毛茛目内发生以后,可能是沿着一条特化和减化的途径发展的。     

Comparative Anatomical Studies on Vessel Elements of Chinese Ranunculaceae

The vessel elements in 77 species of 36 genera of Chinese Ranunculaceae were studied. The vessel elements of Ranunculaceae could be divided into primitive and more specialized groups on the basis of their morphological characters through clustering analysis. The most primitive type of the vessel elements was seen in Asteropyrum, and some vessel elements were considered more primitive, as in Paeonia, Trollius, Actaea, Helleborus, Souliea, Calathodes, Beesia, Caltha, Coptis, Kingdonia, Circaeaster, Adonis, Hepatica, than others. There was a marked difference between Paeonia and other genera of Ranunculaceae. The vessel elements of Paeonioideae and Helleboroideae with follicles were more primitive than Ranunculoideae with achenes. In Thalictroideae, .the vessel elements of Thalictrum with achenes were more specialized than other genera with follicles. All these findings coincided with the evolution of fruits. The character of evolution of vessel elements ran parallel with that of other parts of plant (flower, carpel, petiole, venation). The features of vessel elements in the same genus were at similar evolutional level, however, some difference between species do exist.     

星叶草属2隙节及2裂叶及其系统学意义

报道了存在于星叶草属植物中与单隙节共存的２隙节及与不分裂叶共存的２裂叶。通过分析后认为,这两个现象在该属植物中的出现并不是异常的。     

星叶草科——湖北被子植物一新记录科

报道了湖北种子植物分布1新记录科———星叶草科Circaeasteraceae,含1新记录属———星叶草属Circaeaster,1新记录种———星叶草Circaeaster agrestis Maxim。通过查阅标本对星叶草的性状进行了描述并讨论了其形态变异幅度。本文重绘了星叶草的线条图并提供了野外原色图版。     

Morphological Studies on Circaeaster agrestis Maxim. (1) Process of Embryolo gical Development

The present paper aims at discovering the characters of embryological development of Circaeaster agrestis, which makes up a monotypic genus, Circaeaster, to establish the phylogenetic relationships of the genus. The different opinions on its systematic position among botanists are briefly explained. The embryological studies show that the most important advanced characters of the genus are as follows. The ovule is amphitropous, unitegmic and tenuinucelar; the embryo sac formation is in accordance with the Polygonum type; endosperm formation is of the cellular type, the primary endosperm nucleus dividing to form two cells and the first wall vertical; embryo formation follows the variation of the Caryophyllad type; at the early stage of development of embryo, the integument has been already atrophied and at last disappeared, so that the seed coat is absent in the mature fruit. On the basis of the embryological and some morphological evidence, the authors consider that a close relationship between the genus and Ranunculaceae and its related families seems to be unlikely. The affinities of the genus Circaeaster are still uncertain.     

Chromosome observations of three ranunculaceous genera in relation to their systematic positions

1. The present paper describes the observations of chromosome numbers and karyomorphology of 2 species of 2 endemic genera and I endemic species of Chinese Ranunculaceae: Asteropyrum peltatum (Franch.) Drumm et Hutch. 2n=16, x=8; Kingdonia unifolia Balf. f. et W. W. Sm. 2n=18, x=9 and Calathodes oxycarpa Sprague 2n=16, x=8. The chromosome counts of three ranunculaceous genera are reported for the first time. 2. The morphylogical, palynological and cytological date in relation to the systematic postition of Asteropyrum, Kingdonia and Calathodes within the family Ranunculaceae are diseussed and resulted in following conclusions: (1). On the basis of the basic number x=8 in Asteropyrum, it is further confirmed that this genus is distinct from the r elated genera such as Isopyrum, Dichocarpum and other allied taxa. The comparison of Asteropyrum with Coptis shows that they are identical in short chromosomes, with magnoflorina and benzylisaquinodine type of alkaloides, but different from coptis in the chromosome numbers (T-type), pantocolpate pollens, united carpels and the dorsi-ventral type of petioles. In view of these fundamental morphological and cytological differences, Asterop yrum is better raised to the level of Tribe. However Asteropyrum and Coptis may represent two divaricate evolutional lines of Thalictroideae. (2). The systematic position of the genus Kingdonia has been much disputed in the past. We support the view of Sinnote (1914), namely, the trilacunar in leaf traces “the ancient type”, appeared in the angiosperm line very early, while the unilacunar of Kingdonia may be derived from the trilacunar. On the basis of the chromosome numbers and morphylogical observation, the present writer accept Tamura’s and Wang’s treatment by keeping Kingdonia in Ranunculaceae instead of raising it to a family rank as has been been done by Forster (1961). Kingdonia and Coptis are similar in having short chromosome with x=9, but with one-seeded fruits; therefore it is suggested that placed into Thalictroideae as an independent tribe, indicating its close relationship with Coptideae. (3). Comparing with its allies, Calathodes being with out petals, seems to be more primitive than Trollius. But Calathodes differs from Trollius with R-type chromosomes in having T-type chromosome with x=8 and subterminal centromere. Those characteristics show that it is very similar to the related genera of Thalictroideae. But as Kurita already pointed out that most speci es of Ranunculus have usually large long chromosomes but some species have compar ativelly short chromosomes, therefore we regard T-type and R-type chromosomes appear independently in different subfamilies of Ranunculaceae. According to Tamura, G alathodes seems to be closely related to Megaleranthis, because of the resemblance in follicles. But due to lack of cytological data of the latter genus, the relationship between the two genera still is not clear pending further studies. From the fact that the morphology and chromosomes of the Calathodes differs from that of all other genera of the Helleboroideae, we consider Calathodes may form an independent tribe of its own with a closer relationship withTrollieae.9841     

独叶草叶宏观形态性状的变异式样的初步研究

根据独叶草分布区内 8个居群的叶的 8个宏观性状在散点图上的表现 ,探讨了独叶草的形态变异式样。结果表明 ,独叶草在叶宏观性状上表现出了一定的变异性 ,这种变异性表现在不同居群间及由不同居群组成的区域上 ,但在居群间或由不同居群组成的区域间在性状上有不同程度的重叠。