中国珍稀濒危植物—栌菊木区系性质的评价

栌菊木是菊科的单型属。Ｎｏｕｅｌｉａｉｎｓｉｇｎｉｓ是中国特有的珍稀濒危植物,分布于北纬２４°－３０°和东经９９°４０′－１０３°５０′的康滇地区。关于它的起源和区系性质,许多作者都进行过研究。本文分析了分布区的历史及栌菊木与近缘属Ｇｏｃｈｎａｔｉａ的系统关系,得出结果为：１．栌菊木是康滇地区的特有属,而非金沙江河谷特有;２．它是一个生存在亚热带气候环境中的温带成分,但非热带成分;３．其起源地应是康滇古陆的南部──滇中高原,而不是古地中海地域;４．起源时间大约在中新世末或更晚,当时气候条件与现代滇中地区相似。综上所述：栌菊木是一个（起源于晚第三纪）比较年青的属,并不是起源古老的区系成分。     

栌菊木的等位酶分析及其在生物地理和保护生物学上的意义

对我国西南特有的菊科单种属植物栌菊木10个居群、149个个体、11个酶系统及16个酶位点的水平淀粉凝胶电泳分析表明,栌菊木的遗传多样性水平在特有种中较高,在居群水平上,平均每个位点的等位基因数A=1．1—1．4,多态位点百分数P=6．3％—43．8％,实际杂合度Ho=0．063～0．250,期望杂合度He=0．043～0．194;物种水平上A=1．6,P=37．5％,Ho=0．143,He=0．141。居群间遗传一致度I=0．902—1．000,杂合性基因多样度比率FST为0．2395。栌菊木居群间分化程度较大,云南南盘江流域碧云寺居群遗传多样性较低,明显低于金沙江流域的居群。栌菊木可能是来自冈瓦纳古陆祖先的后裔,可能是古地中海退却以后在金沙江干热河谷分化出来的特有属,并且可能由于湿度等生态因子的限制,其分布区未能进一步扩大,仅在南盘江流域形成零散分布。等位酶分析结果还表明栌菊木遗传多样性总体水平较高,建议对遗传多样性较高的金沙江流域的居群加以保护。     

10种菊属(Dendranthema)植物的细胞学研究

对菊属在中国分布的１０种２０ 个居群的材料进行了细胞学研究,首次报道了异色菊、银背菊、楔叶菊的染色体数目和核型,以及菊的染色体数目新纪录,并结合前人的工作分析了核特征和演经趋势,及其与该属分类的关系     

10种菊属(Dendranthema)植物的细胞学研究

对菊属（Dendranthema）在中国分布的10种20个居群的材料进行了细胞学研究,首次报道了异色菊（2n＝18,36）、银背菊（2n＝56）、楔叶菊（2n＝18,72）的染色体数目和核型,以及蒙菊（2n＝18）的染色体数目新纪录,并结合前人的工作,分析了菊属的核型特征和演化趋势,及其与该属分类群的关系。     

两种羽叶菊属植物(菊科:千里光族)的细胞学研究及其系统学意义

该研究首次报道了滇羽叶菊和台湾刘寄奴的染色体数据。结果表明:两者的染色体数量都为48,核型公式均为2n=2x=36m+10sm+2st,与前人报道的刻裂羽叶菊的核型稍有不同。两者的染色体形态均由大到小逐渐变化,核型二型性不明显,但前者染色体明显比后者大。这说明羽叶菊属染色体基数确实应为x=24,且染色体大小在种间有较大差异。细胞学证据表明,该属与蒲儿根属中染色体基数为x=24的类群以及狗舌草属确实近缘。     

10种菊属(Dendranthema)植物的细胞学研究

对菊属(Dendranthema)在中国分布的10种20个居群的材料进行了细胞学研究,首次报道了异色菊(2n＝18,36)、银背菊(2n＝56)、楔叶菊(2n＝18,72)的染色体数目和核型,以及蒙菊(2n＝18)的染色体数目新纪录,并结合前人的工作,分析了菊属的核型特征和演化趋势,及其与该属分类群的关系。     

东北产苍术属植物的细胞学研究

报导了中国东北产三种苍术属植物的核型资料,核型公式分别为;北苍术「Ａｔｒａｃｔｙｌｏｄｅｓ ｃｈｉｎｅｎｓｉｓ（ＤＣ．）Ｋｏｉｄｚ．」Ｋ（２ｎ）＝２４＝１２ｍ＋６ｓｍ＋６ｓｔ（４ＳＡＴ）,关苍术「Ａ．ｊａｐｏｎｉｃａ Ｋｏｉｄｚ．」（２ｎ）＝２４＝１４ｍ＋１０ｍ（２ＳＡＴ）朝鲜苍术「Ａ．ｋｏｒｅａｎａ（Ｎａｋａｉ）Ｋｉｔａｍ．」Ｋ（２ｎ）＝２４＝１０ｍ＋１４ｓｍ（２ＳＡＴ）,三者核型对称性均为２Ｂ     

国产稗属植物的细胞学研究

对国产７种（含变种）稗属Ｅｃｈｉｎｏｃｈｌｏａ植物的细胞学进行了初步研究。９个供试材料的体细胞分别表现两种染色体数目２ｎ为３６或５４。除光头稗Ｅ．ｃｏｌｏｎｕｍＬ外,分析了其余种的核型,其结果为：稗Ｅ．ｃｒｕｓ．ｖａｒ．ｃｒｕｓｇａｌｌｉ２ｎ＝５４＝５８ｍ＋６ｓｍ;西来稗Ｅ．ｃｒｕｓ．ｖａｒ．ｚｅｌａｙｅｎｓｉｓ（Ｈ．Ｂ．Ｋ．）Ｈｉｔｃｈｃ ２ｎ＝５４＝４２ｍ（２ＳＡＴ）＋１２ｓｍ（４ＳＡＴ）;     

蟛蜞菊属和孪花菊属(菊科-向日葵族)的细胞学研究

研究了菊科向日葵族鳢肠亚族蟛蜞菊属(Sphagneticola O. Hoffm.)和孪花菊属(Wollastonia DC. ex Decne.)各2种植物的染色体数目和染色体形态。蟛蜞菊[S. calendulacea (L.) Pruski]的染色体数目为2n=50, 核型公式为2n=18m+30sm+2st,南美蟛蜞菊[S. trilobata (L.) Pruski]的染色体数目为2n=56, 核型公式为2n=24m+28sm+4st, 孪花菊[W. biflora (L.) DC.]的染色体数目为2n=30,核型公式为2n=24m+4sm+2st,山孪花菊[W. montana (Blume) DC.]的染色体数目为2n=74, 核型公式为2n=37m+31sm+6st。根据上述结果并结合以前的有关资料,推测蟛蜞菊属的染色体基数可能为x=14和x=25,而不应是x=15。该属的3个新世界热带种[S. brachycarpa (Baker) Pruski、S. gracilis (Richard) Pruski和南美蟛蜞菊]可能都基于x=14, 其中S. gracilis为二倍体(2n=2x=28), S. brachycarpa和南美蟛蜞菊为四倍体(2n=4x=56); 唯一的亚洲种(蟛蜞菊)可能是基于x=25的二倍体(2n=2x=50)。染色体资料不支持将山孪花菊(x=37)这一植物置于孪花菊属(x=15)中。     

新分类系统下长蒴苣苔亚科(苦苣苔科)细胞学研究概述

在最新分类系统框架下对长蒴苣苔亚科(Didymocarpoideae)的染色体资料进行了详细的整理和分析,结果表明,长蒴苣苔亚科的细胞学研究仍存在不足,尤其在种级水平上的研究不足25%,且存在一些属的染色体数据空白的现象。在新的分类系统下,一些修订后的属染色体数目表现出一致性或更加具有合理性,但也存在一些属的染色体数目变异仍十分复杂,如汉克苣苔属(Henckelia)和长蒴苣苔属(Didymocarpus)。基于已有的染色体数据,对长蒴苣苔亚科内一些重要属的染色体进化模式及其对物种分化的影响进行了探讨,推测染色体数目的多倍化及非整倍化进化可能对各类群的物种分化具有重要作用,但需要今后利用基于DNA探针的荧光原位杂交技术并结合分子系统学和基因组学研究才能深入地解析染色体的进化模式及其对物种分化的影响。     

五种橐吾属植物的核型研究

首次报道了5种国产橐吾属植物的核型,结果如下：东俄洛橐吾(Ligularia tongolensis)核型为2n=58=32m 14sm 12st;侧茎橐吾(L.pleurocaulis)四川稻城居群核型为2n=58=24m 32sm 2st 3～5B,云南中甸居群核型为2n=58=36m 22sm;云南橐吾(L．yunnanensis)核型为2n=58=28m 30sm;叶状鞘橐吾(L．phyllocolea)核型为2n=58=30m 24sm 4st 1B;浅苞橐吾(L．cynthceps)核型为2n=58=24m 34sm。5种橐吾染色体数目都为58。在叶状鞘橐吾和四川稻城产侧茎橐吾中发现有B染色体存在,这在以前对橐吾属及近缘属植物的核型研究中未见报道。     

A Cytological Study on Acanthochlamys bracteata P. C. Kao (Acanthochlamyaceae)

Chromosome number, 2n=38, is reported for Acanthochlamys bracteata P. C. Kao for the first time. This number and the basic chromosome number x= 19 imply the isolated position of this genus in monocotyledons. The affinities are discussed based on the cytological evidence. It seems that Acanthochlamy is more closely related to Aspidistra and Tupistra of the Liliaceae than to any of theAmaryllidaceae.     

七种灯台报春组植物的细胞学研究

对报春花科（Primulaceae）报春花属（Primula）灯台报春组植物Section Proliferoe的7种报春进行了细胞学研究,其中腾冲灯台报春和川东灯台报春的核型分析为首次报道,结合已报道的灯台报春组其它植物的细胞学资料进行统计分析,结果表明灯台报春组植物在染色体基数、染色体形态、着丝点位置及染色体对称性上都具有很高的一致性,在灯台报春组有核型记录的种类中,其核型都属于Stebbins的2A型或2B型,核型差异很小,染色体基数均为x=11,推测其可能与报春花属中具有相同染色体基数的组亲缘关系更近。结合已发表的灯台报春组植物的细胞学资料及它们的形态特征,对其系统演化关系进行了比较分析,以期对该组的系统学及演化关系提供一些证据。     

High genetic diversity vs. low genetic differentiation in Nouelia insignis (Asteraceae), a narrowly distributed and endemic species in China, revealed by ISSR fingerprinting

BACKGROUND AND AIMS: Nouelia insignis Franch., a monotypic genus of the Asteraceae, is an endangered species endemic in Yunnan and Sichuan Provinces of China. Most of the populations are seriously threatened. Some of them are even at the brink of extinction. In this study, the genetic diversity and differentiation between populations of this species were examined in two drainage areas. METHODS: DNA fingerprinting based on inter-simple sequence repeat polymorphisms was employed to detect the genetic variation and population structure in the species. KEY RESULTS: Genetic diversity at species level was high with P=65.05% (percentage of polymorphic loci) and Ht=0.2248 (total genetic diversity). The coefficient of genetic differentiation among populations, Gst, which was estimated by partitioning the total gene diversity, was 0.2529; whereas, the genetic differentiation between populations in the Jinsha and Nanpan drainage areas was unexpectedly low (Gst=0.0702). CONCLUSIONS: Based on the genetic analyses of the DNA fingerprinting, recent habitat fragmentation may not have led to genetic differentiation or the loss of genetic diversity in the rare species. Spatial apportionment of fingerprinting polymorphisms provides a footprint of historical migration across geographical barriers. The high diversity detected in this study holds promise for conservation and restoration efforts to save the endangered species from extinction.     

Cytological Investigation of Taiwania flousiana Gaussen (Taxodiaceae)

The present paper deals with the cytological investigation of Taiwania flousiana Gaussen. The somatic chromosomes in root-tip cells of the plant are found to be 2n=22 for the first time, all with median and submedian constrictions. According to the terminology defined by Levan et al.^[11], the karyotype formula is K(2n)=16m+6sm, which belongs to “2B” of Stebbins'^[16,17] karyotypic symmetry and is generally regarded as a relatively primitive one. The species' chromosome complement is 2n=22=4L+6M₂+8M₁+4s according to the standard defined by Kuo et al.^[10] based on relative length. The nucleolus number in resting root-tip cells of T. flousiana is found to be 1-5 (Table 3). The percentage of cells with two nucleoli is 77.6%, and those with five nucleoli, the highest number ever found by me, is only 1.6%. A few cells with many micronuclei are found in this species for the first time (Plate 1, 1). Although T. flousiana and T. cryptomerioider have the same “2B” type of karyotypic symmetry, the differences in the arm ratio and the index of the karyotypic asymmetry (Table 2) show that the karyotype of the former is less symmetrical than that of the latter, so the former may be a little more advanced than the latter. The basic karyotype (2B) of Taiwania is more related to that of Cunninghamia (1B)^[3] than to that (1A) of Metasequoia^[5], Glyptostrobus^[4] and Cryptomeria^[3]. Wang et al.^[1], have reached the similar conclusion from the embryological study.     

中国产3种防己科植物细胞学研究

报道了3种国产防己科植物的染色体数目。金线吊乌龟Stephania cepharantha Hayata为二倍体2n=22,部分居群的一些个体存在B染色体;轮环藤Cyclea racemosa Oliv．为二倍体2n=24;木防己CDcculus orbiculatus(L)DC为四倍体2n=4x=52.3个种的染色体基数分别为x=11,12,13。观察了木防己的小孢子母细胞减数分裂过程,其减数分裂过程正常,且花粉粒具较高活性。