Diploid and tetraploid distribution of Allium przewalskianum Regel. (Liliaceae) in the Qinghai-Tibetan Plateau and adjacent regions

Polyploidization plays an important role in generating the current high diversity of plants. Studies of distributional patterns of diploids and derivative autopolyploids have provided important insights into evolutionary processes and cryptic speciation of polyploidization within species defined on the basis of their morphology. However, few studies have been designed to examine distributions of infrageneric diploids and polyploids on the Asian Qinghai-Tibetan Plateau (QTP). Allium przewalskianum occurs widely on the QTP and in adjacent regions, at altitudes ranging from 2000m to 4500m. We collected a total of 844 individuals from 62 populations and determined their cytotypes over the entire distribution range of this species. Tetraploids tend to occur at high altitudes; however, the positive relationship between the ploidy and altitude was only marginally significant (P < 0.05). Contact zones between diploids and tetraploids were recorded on the eastern QTP from north to south. Four populations were found to harbor both cytotypes, but no triploid individuals. The wider distribution of tetraploids may be mainly due to their greater colonization ability in the new niches created by the Quaternary climatic oscillations in the QTP region. Our results offer a fundamental framework for studying evolutionary origins, adaptations and cryptic divergences of polyploids within this species complex based on molecular and/or ecological examinations in the future.

Origin of the Qinghai-Tibetan Plateau endemic Milula (Liliaceae): further insights from karyological comparisons with Allium

Milula, a monotypic genus endemic to the Qinghai-Tibetan Plateau, was found to be nested deeply within Allium by the molecular phylogeny despite the aberrant morphology. It remains unknown what had contributed to the rapid evolution of morphology and origin of this exceptional species. In contrast to a previous report of its karyotypes with 2n = 16 = 8M+8SM (2SAT), similar to most species of Allium, a rather different karyotype, 2n = 20 = 4M +10SM+6T (2SAT), was found in examined 31 individuals from 6 populations of M. spicata distributed in the central Tibet. Karyotypes of 7 Allium species occurring in the Qinghai-Tibetan Plateau were further reported. The basic number x = 8 was confirmed for all of them and their karyotypes consist mainly of metacentric and submetacentric chromosomes with rare subterminal and terminal chromosomes. The karyotype of M. spicata is distinctly different from that of most Allium species occurring in the plateau through a complete comparison of all available species in this region and adjacent areas. However, the same chromosome number and similar karyotypic structure were found in A. fasciculatum of Sect. Bromatorrhiza, indicating a possible close relationship between them. But this similarity is contradictory to the preliminary molecular phylogenetic analysis that Milula was closely related to A. cyathophorum of Sect. Bromatorrhiza with x=8, but the other species with x=10 and 11 in this section were clearly placed in the other clade. We therefore suggested that the paralleling evolution from x=8 to x=9, 10 and 11 with increasing asymmetry of karyotype possibly due to the chromosomal Robertsonian translocation might occur separately in the two recognized phylogenetic lineages of Allium. In addition to aneuploidy and following change of the chromosomal structures, the habitat isolation due to the recent uplift of the Qinghai-Tibetan Plateau and the Quaternary climatic oscillation, plays a greater role in origin of Milula and other endemic species (genera) with aberrant morphology from their progenitors.

Asphodelus fistulosus L. (Liliaceae) subespontáneo en la Argentina (nota breve)

p.113-114

Liliaceae novae Africae australis gerbarii regii Berolinensis

Descriptae ab J. G. Baker

[Lilium martagon (Liliaceae)]

R. Anheisser

Improved germination of the Australian natives: Hibbertia commutata, Hibbertia amplexicaulis (Dilleniaceae), Chameascilla corymbosa (Liliaceae) and Leucopogon nutans (Epacridaceae)

Hibbertia commutata (Steudel), H. amplexicaulis (Steudel), Chameascilla corymbosa [(R.Br.) F.Muell. Ex Benth.] and Leucopogon nutans (E. Pritzel) are four Australian species that are difficult to germinate during mine-site rehabilitation. Laboratory germination trails were conducted to identify dormancy mechanisms and to improve germination response. Treatments applied to all species included scarification and scarification followed by soaking seeds in smoke water (1, 5 or 10%) or gibberellic-acid solution (50, 200 or 1000 muM). Additional treatments with kinetin solution (50, 200 or 1000 muM) and smoke water (50 or 100%) were applied to scarified or unscarified seeds of C. corymbosa. Thermal-shock treatment was applied to L. nutans fruit, some of which were subsequently scarified and subjected to both smoke water (10%) and gibberellic-acid solution (1000 muM). Significant germination increases were obtained by using dormancy-breaking treatments on H. commutata ( from 12.8 to 76.0%), H. amplexicaulis (from 6.8 to 55.1%) and C. corymbosa (from 48.5 to 86.4%). Scarification alone increased germination of both Hibbertia species, suggesting that these species display a physical seed coat-imposed dormancy mechanism. Germination of H. amplexicaulis was further increased by the application of gibberellic-acid solution, indicating a possible embryo-imposed dormancy mechanism. Scarification followed by the application of smoke water produced the highest germination response for C. corymbosa seeds. Scarification alone did not significantly increase germination, inferring the existence of a smoke-responsive embryo dormancy mechanism. Seeds of L. nutans, although viable, failed to germinate and are thought to display complex seed coat- and embryo-imposed dormancy mechanisms.

Origin of facultative heterochromatin in the endosperm of Gagea lutea (Liliaceae)

Peer reviewed

Origin of facultative heterochromatin in the endosperm of Gagea lutea (Liliaceae)

Peer reviewed

国产贝母属（百合科）的系统学研究

作者通过实地调查，栽培观察，大量查阅标本，对国产贝母属(Fritillaria L.)的形态性状作了深入的分析，认为贝母属中植株大小，茎生叶先端卷曲与否，花的数目、花梗的长短、花被片颜色等性状易受生境的影响;而鳞茎所具鳞片的数目，植株最下一轮叶的形状及排列，花部蜜腺的形状，花柱柱头的分裂程度，雄蕊花丝在发育完后的长短，蒴果的形状等性状受生境的影响较小，但在栽培情况下，这些性状有时也会发生变化．此外，作者首次报道了部分国产贝母属种类的核型和花粉形态．在此基础上对我国贝母属进行了系统整理，将正式发表的138个分类名称（包括80个种、52个变种、5个变型、1个栽培变型）归并成24种l变种，并对国产贝母组(Seclion Fritillaria)的种间关系作了初步探讨;同时，对该属的次级分类也作了修订．根据有关，F.karelinii花粉学和细胞学资料，以及邻近4个种的形态特征及分布特点，我们支持J.G..Baker(1874)的观点将该类群保留在贝母属内而不同意A.S.Lozin-Lozinskaya(1935)，A.Takhtajan(1987)将其单立成属也不同意W.B.Turrill &J.R.Sealy(1980)将其并入贝母组(Sect.Fritillaria)，而将该类群做为贝母属中的一个新组——砂贝母组(Sect.Rhinopetalum (Fish. ex Alex.) Y.B.Luo)．并认为该组与贝母组关系较近．作者通过上述工作及查阅世界各地有关贝母属的文献，认为贝母属内最原始的类群是Sect. Fritillaria，而Sect.Petillium，Sect.Rhinopetalum和Sect.Theresia是演化水平中等的类群．Sect.Liliorhiza则是演化水平最高的一类．通过对该属组(Section)级及种级分布式样的分析，认为伊朗一土兰区不仅是组的多度中心，并且也是多样化中心;在种级水平上，地中海区是分布的多度中心，而种级多样化中心则在伊朗一土兰区;此外，在伊朗一土兰区还保留着一些较原始的类群，因而，该区可能是贝母属的起源中心，最后，作者对贝母属的起源时间、散布途径及现代分布格局形成的原因进行了初步探讨．

百合科黄精族的系统学研究

黄精族隶属于广义的百合科，通过对其研究历史的回顾，指出了它目前存在的问题，即(1)族的概念和范围不清、(2)属间的界限模糊、(3)族内各属的系统排列不明确．针对这些问题，本文从形态、解剖、胚胎、孢粉和细胞方面对族内各类群进行了野外调查和一些实验工作，本此基础上，并结合前人的工作，对黄精族的系统发育进行了探讨． 一, 形态本文通过黄精族各属大量标本，尤其是国产类群标本的认真研究，并结合6个多月的野外调查资料，分析了本族植物21个形态性状及其状态在属间和属内的分布，指出了一些性状的稳定性及其系统学价值， 二，解剖本文对黄精族5属17个种的茎、根状茎及子房进行了解剖学观察，同时对7属41种植物的叶表皮进行光镜观察，并对5属12种的叶表皮进行扫描电镜的观察，结果表明：(1)七筋姑属花葶的维管柱缺乏纤维鞘，这和本族其它类群不同．(2)扭柄花属、黄精属、竹根七属和鹿药属植物子房中具草酸盐针晶，而七筋姑属和万寿草属未发现这种晶体．(3)本族植物的气孔器均为无规则型，但邻近细胞及其周壁的形状在不同类群中是不同的，据此我们将本族叶表皮划分为七个类型，并认为叶表皮邻近细胞呈多边形、周壁直是黄精族叶表皮最基本的形式． 三，胚胎本文对黄精族3属4种植物以及铃兰(Convallaria majalis)进行了胚胎学研究，其中小玉竹(Polygonatum humile)和铃兰得到了完整的胚胎学资料，实验结果显示(1)黄精族植物小孢子发生过程中胞质分裂均为连续型，胚乳发育为核型;(2)小玉竹的胚囊发育方式为葱型，鹿药(Smilacina japonica)为英地百合型．万寿竹(Disporum cantoniense)和长蕊万寿竹(D. bodinicri)为蓼型，铃兰为葱型或英地百合型;(3)周缘细胞的有或无在小玉竹，鹿药和铃兰中是不稳定的． 四，孢粉本文对6属42种植物花粉进行了扫描电镜观察，结果表明(1)萌发孔的类型和数目在本族中不稳定，系统价值不大;(2)花粉外壁纹饰比较稳定，是一个十分重要的分类学性状．我们将黄精族植物的花粉外壁纹饰划分为9种类型．并认为孔穴型是一种原始类型，其它类型是由它演化而成， 五，细胞在前人工作的基础上，通过与其它性状的综合分析，本文认为黄精族植物有五种原始染色体基数：七筋姑属x=7;万寿竹属和扭柄花属x=8;黄精属x＝9：鹿药属和舞鹤草属x＝ 18;竹根七属x=20． 在上述实验结果的基础上，结合前人的工作，对黄精族的各种性状进行了分析，本文得出如下结论： 1．包括万寿竹属、扭柄花属、七筋姑属、黄精属、竹根七属、鹿药属和舞鹤草属的黄精族是一个单系类群． 2．本文赞同Dahlgren et al．(1985)，Tahktajan (1987)对黄精族系统位置的处理，即它与铃兰族，蜘蛛抱蛋族和沿阶草族关系较近，且共同组成铃兰科．相比之下，黄精族是该科中比较原始的一个族. 3．本文在性状分析的基础上，总结出20个比较稳定、系统价值较大的性状，并指出了它们的演化趋势;同时总结出黄精族原始类群应具有如下特征：(1).具细线形根状茎;(2).地上茎具分枝;(3).叶茎生;(4).具腋生的圆锥或总状花序;(5).花为三基数，花被片离生;(6).花被片具多条开放型脉;(7) .胚珠多数;(8).胚囊发育为单孢子型;(9).厚珠心胚珠;(10) .花粉外壁具覆盖层． 4．本文认为黄精族植物可分为三支：一是以染色体基数x＝9及其衍生的类群，包括黄精属，竹根七属、鹿药属和舞鹤草属;二是以x=8为基数的一支，它包括万寿竹属和扭柄花属;三是七筋姑属单独形成的一支，它的染色体基数x＝7．同时认为万寿竹属是本族比较原始的一个类群． 5．本文认为东亚北方是黄精族植物起源地． 6．本文赞同汤彦承(1978．见汪发缵、唐进1978)对卵叶扭柄花(Streptopus ovalis (Ohwi) Wang et Y.C．Tang)的分类学处理，而不赞同汪发缵、唐进(1983)把金佛山鹿药(Smilacina jinfoshanica Wang et Tang)从鹿药属转隶至黄精属的观点． 7．本文认为鹿药属和舞鹤草属亲缘关系较近，但区别特征明显，从而不赞同LaFrankie (1986),李恒(1990)将二者合并的观点。

萱草属的进化与分类

根据现有记载，萱草属约有20种，主要分布在东亚，由于种间在外部形态和核型上的高度相似性，加之长期人工栽培，使本属植物的分类成为一个难题，我们做了大量的野外调查和温室栽培试验，获得了一些有意义的观察结果，对核型变异做了详细定量分析：系统观察了花粉扫描电镜特征，为了揭示属内可能的表征和分支关系，运用聚类分析，主成分分析及简约分析对属下类群做了定量研究．本文得到如下主要结论． 1．虽然迄今为止许多核型观察结果未能得到有分类学意义的结论，运用数量分析方法比较各分类群核型定量变异结果表明，其分类学意义是明显的，例如，北黄花菜、黄花菜和小黄花菜三者外部形态很一致，核型亦高度相似：大苞萱草和多花萱草的核型公式虽与前三者相同，但已出现明显的数量变异．同样，北萱草，折叶萱草和西南萱草虽有相同核型公式，亦出现明显数量变异．萱草则与所有其他类群的核型均有明显差别．核型对称性分析表明，臂比不对称性出现一个由低到高的演变序列：但长度不对称性与此无明显相关性．萱草和折叶萱草的臂比不对称性最低，西南萱草和北萱草升高，黄花菜，大苞萱草和多花萱草等最高． 2．观察到三种类型花粉;舟形具网纹，舟形具疣纹和亚球形具疣纹．萱草，北萱草，大苞萱草，北黄花菜，黄花菜，小黄花菜及多花萱草具第一种类型花粉;折叶萱草和西南萱草具第2种类型花粉;矮萱草具第三种花粉．以广义百合科其他类群作为复合外类群进行比较，推测花粉形态的演化序列为：舟形具网纹一舟形具疣纹一亚球形具疣纹． 3．在外部形态上，萱草因具二叉分枝花序，叶型苞片，根膨大适中，花蕾顶部绿色及花筒占花被比例较小等原始性状状态，结合不对称性较低的核型特征和舟形具网纹花粉特征，是现存种类中最原始类群;折叶萱草及北萱草等具较短的花筒，二叉分枝花序，单色花被及花蕾部绿色等特征显得进化程度不高．黄花菜因具夜间开花习性，长花筒，叶鞘红色等状态被认为是进化类群，大苞萱草高度压缩的花序形成头状花序，具总苞状宽大苞片及绳索状根被认为是特化类群，矮萱草个体矮小，单花，具亚球形疣纹花粉亦被认为是高度特化类群．外部形态，花粉特征，核型及地理分布之间存在着相关性;随地理水平分布由南向北，外部形态特征由原始到进化，核型不对称性由低到高：随地理垂直分布由低向高，形态特征由复杂到简化，核型不对称性由低到高，花粉形态由舟形具网纹到舟形具疣纹再到亚球形具疣纹，这两种趋势结合起来构画出了本属植物演化和地理分布的基本轮廊． 4．萱草是一个孤立的属，没有明确的外类群可供比较．在现存类群中．Dahlgren等(1985)认为本属与分布在非洲，地中海地区，西亚及中亚的Asphodeloideae（亚科）有较多的共有特征．本文比较了两个类群之后发现，萱草不但在许多一般特征上与Asphodeloideae -致，而且在小孢子同时型发生及含蒽醌等被认为是Asphodeloideae典型属性的特征上亦与后者相同．这些共有特征显示出二 者在系统发育上一定的联系．进一步比较发现两者在有差异的特征中，萱草属显得较为进化．二者的分布区是完全不同的;Asphodeloideae分布在中亚及其以西地区和非洲，而本属分布在东亚，延及西伯利亚，据本文分析，欧洲生长的一个种(H.lilioasphodelus，北黄花菜)是归化类群．北美和台湾没有自然分布，但栽培植物均生长良好，而且已有归化植物．由此似乎可以推测，本届的祖先与Asphodeloideae的祖先有亲缘关系，这种关系似可远溯到第三纪古地中海时期，或许当时与Asphodeloideae祖先有关系的一个分支分布于古地中海东南缘的康滇古陆，即与现今横断山地区相应的地区，由于喜玛拉雅造山运动引起的地质，地理和气候剧变，某些类群灭绝了，一个类群发展成现今的萱草属． 5．由于本属各分类群间形态及核型相似性程度较高，种间极易（人工）杂交，似无必要在属与种间增设组或系，根据本文研究结果及参考有关分类文献（国外种类），我们将萱草属处理为10种2亚种13变种：H.darrowiana Hu;小萱草(H.dumortieri Morr.)及北萱草(var. esculenta (Koidz.) Kitamura;西南萱草(H.forrestii Diels);萱草(H.fulva (L.) L.)及var. aurantiaca (Baker) Hotta, var. disticha (Donn.) Baker，重瓣萱草(var. kwanso Regel)，var. littorea (Makino)Hotta，长菅萱草(var. longituba (Miq.) Maxim，var. maculata Baroni，var. pauciflora Hotta et Matsuoka, var. rosea Stout, var. sempervirens (Araki) Hotta; H. hakuunensis Nakai;北黄花菜 (H. lilioasphodelus L. Var. lilioasphodelus)及黄花菜(ssp. citrina (Baroni) Xiong)，小黄花菜(ssp. minor(Mill.) Xiong)，var. corcana (Nakai) Xiong;大苞萱草 (H. middendorfii Trautv. et Mey var. middendorfii)及var. exaltata (Stout) Kitamura，长苞萱草(var. longibracteata Xiong);多花萱草(H. multiflora Stout);矮萱草(H. nana Smith ct Forrest);折叶萱草(H.plicata Stapf)。