Development of 10 microsatellite loci for Rheum tanguticum (Polygonaceae)

Rhubarb is an important Traditional Chinese Medicine. However, the wild resource has been declining. In order to design appropriate conservation methods for the official species across their natural distributions, it is important to characterize their genetic diversity. Here, we describe the development of 10 new microsatellite loci for AC/TG/CCA in Rheum tanguticum. The microsatellites were enriched using the combined biotin capture method. The polymorphism of each locus was further assessed in 12 individuals from four geographically distinct populations of this species. The number of alleles ranged from three to seven and the expected heterozygosity ranged from 0.53 to 0.73. All markers have been checked in the other three species in the genus and two of them together comprise the official medicinal rhubarb resource, with R. tanguticum. These microsatellite markers could. provide a useful tool for genetic and conservation studies of the rhubarb species.

唐古特大黄五个居群的核型

报道了唐古特大黄（Rheum tanguticum）5个居群的染色体数目和核型,结果如下：大武、柯曲、达卡三个居群均为2n=2x=22=2sm＋20m;吉卡居群为2n=2x=22=20m＋2M;松潘居群为2n=2x=22=2sm＋18m＋2M。大武,柯曲和吉卡居群核型类型属于1A型,达卡和松潘居群属于2A型。Q型聚类分析结果表明,5个居群在核型上存在一定分化,这可能是由不同的生境造成的。

果洛唐古特大黄染色体观察

对蓼科(Polygonaceae)植物唐古特大黄(Rheum tanguticum Maxim.ex Balf.)染色体核型进行了研究.结果表明,唐古特大黄体细胞染色体数目为2n=22;核型公式为K(2n)=22=20 m+2 sm,核型为"1A"型,少数细胞中发现有随体存在.

唐古特大黄染色体的核型分析

目的对蓼科（Polygonaceae）植物唐古特大黄（Rheum tanguticum Maxim、ex Balf．）染色体核型进行研究。方法采用常规压片方法，并结合显微摄影对染色体进行检测分析。结果唐古特大黄体细胞染色体数目为2n=22；核型公式为K（2n）=22=20m＋2sm，核型为“1A”型。结论唐古特大黄染色体的核型属于较原始的类型。

高山植物唐古特山莨菪和唐古特大黄对强太阳辐射光能的利用和耗散特性

以西宁地区人工栽培的唐古特山莨菪（Anisodus tanguticus）和唐古特大黄（Rheum tanguticum）为材料，比较研究了两典型高山植物对青藏高原强太阳辐射光能的利用和耗散特性。PSⅡ反应中心的最大光化学效率（Fv／Fm）、实际光化学量子效率（ФPSⅡ）和光合功能的相对限制（L（PDF））的分析表明，强太阳辐射会导致光合作用的光抑制，但并不造成PSⅡ反应中心的不可逆破坏。猝灭分析表明，唐古特山莨菪的光化学猝灭系数（qp）显著小于唐古特大黄，非光化学猝灭（NPQ）和（qN）则相反（P〈0．05），意味着唐古特山莨菪将PSⅡ反应中心吸收的过剩光能以热耗散等非光化学过程消耗的能力大于唐古特大黄，因而降低了用于光化学反应的份额。qN的3组分中，QNf所占比例较大；尽管相对份额很小，中午强光下两高山植物的qNs都有增大趋势，表明它在过剩光能的非光化学耗散中也起重要作用。NPQs和qNs的日变化趋势很相似；同样，MPQF为NPQ的主要组分，且唐古特山莨菪的NPQF和qNF显著大于唐古特大黄（P〈0．05）。唐古特山莨菪PSⅡ天线色素吸收光能中分配于光化学反应的相对份额（P）始终低于唐古特大黄，而用于天线热能耗散的相对份额（D）则大于唐古特大黄，两者都具有极显著差异（P〈0．01）。以上结果表明，唐古特山莨菪的垂PSⅡ较唐古特大黄小是因为PSⅡ天线色素吸收的光能中分配于光化学反应的相对份额或光化学猝灭的比例较小，而分配于天线热耗散的相对份额或非光化学过程的比例较大的缘故。唐古特山莨菪的NPQ和qN较大，与NPQF和qNf以及NPQs和qNs都显著大于唐古特大黄有关（P〈0．05）。

青藏高原几种典型高山植物的光合特性比较

选用西宁地区人工栽培的高山植物唐古特大黄（Rheum tanguticum）、山莨菪（Anisodus tanguticus）和麻花艽（Gentiana straminea），比较了3种高山植物之间光合作用的光响应和CO2响应特性，叶片光合色素以及UV—B吸收物质的差异；并以低海拔植物菘蓝（Isatis indigotica）为对比，分析了高山植物与低海拔植物的差异。结果表明：与低海拔植物菘蓝相比，3种高山植物光合作用的表观量子效率（AQY）都偏低；唐古特大黄叶片的AQY、羧化效率（CE）和光呼吸速率（Rp）都很低，净光合速率（Pn）的光响应曲线在全日照光辐射范围内并没有达到完全饱和，这与单位面积叶片具有较高的光合色素以及UV—B吸收物质有关；麻花艽植物与唐古特大黄一样，具有较高的UV-B吸收物质和光合色素含量，但其Rp较高，加之Pn受气孔限制较为明显，故其光合作用的饱和光强很低，Pn相对于其它3种植物也较低；山莨菪与低海拔植物菘蓝的光合特性很相似，都具有较高的AQY和CE。这些结果表明，3种高山植物的光合特性有较大差异，但并没有一致的相对于低海拔植物的共性。4种植物Pn的胞间CO2浓度（G）响应曲线在CO2饱和点以后都表现为无机磷（Pi）再生限制，其吃的变化与CO2饱和点以后的最大Pn的变化基本一致。

唐古特大黄休眠芽诱导植株再生

1植物名称唐古特大黄(Rheum tanguticum),又名鸡爪大黄.2材料类别休眠芽.3培养条件分化培养基:以white、B5和190-2为基本培养基,附加6-BA 1.0～3.0 mg.L-1(单位下同)+NAA 0～0.2+肌醇200+CH 300.增殖培养基:MS+6-BA 3.0+NAA 0.1+肌醇200+CH 300.诱根培养基:MS+NAA 0.5+肌醇200+CH 300.上述培养基均附加3%蔗糖、0.5%琼脂,pH 5.8.培养温度为(20±1)℃,光源为日光灯,光照度为2 000 lx,光照时间18 h?d-1.

唐古特大黄的离体快速繁殖

1植物名称唐古特大黄(Rheum tanguticum),又名鸡爪大黄.2材料类别无菌种子苗.3培养条件种子萌发培养基:(1)MS无激素培养基.前期分化培养基:(2)MS+2,4-D 1 mg?L-1(单位下同)+KT 1+ZT 0.5+6-BA 0.5.后期分化培养基:(3)MS+2,4-D 1+KT 2+ZT 0.5+6-BA 1.以上3种培养基均附加CH 300、肌醇200、3%蔗糖、5 g?L-1琼脂粉.生根培养基:(4)MS+NAA 1+3%蔗糖;(5)1/2MS+NAA 1+3%蔗糖;(6)1/2MS+NAA0.5+1.5%蔗糖;(7)1/2MS+NAA 0.5+3%蔗糖;(8)1/2MS+NAA 1+1.5%蔗糖.pH 5.8.培养温度为(25±1)℃,光源为日光灯,光照度为2 000～3 000 lx,光照时间12 h?-1

唐古特大黄组织培养技术的研究

试验选用唐古特大黄(Rheum tanguticum Maxim.ex Regel.)种子萌发的无菌苗及无菌苗子叶、下胚轴、胚根和幼根作为材料,研究唐古特大黄不同外植体的离体培养技术.结果表明,唐古特大黄的无菌苗和无菌苗子叶、下胚轴、胚根和幼根都可以作为离体培养的良好外植体.唐古特大黄的最适分化培养基是:B5+NAA 0.1mg/L+6-BA 3 mg/L;最适生根培养基是:1/2 MS+NAA 1 mg/L+3%蔗糖或1/2 MS+NAA 0.5 mg/L+3%蔗糖;愈伤组织诱导培养基是:MS+2,4-D 1 mg/L+NAA 1 mg/L+6-BA 1 mg/L.

Pollen morphology and its in systematic and ecological significance in Rheum (Polygonaceae) from China

Pollen morphology of 40 species of Rheum, belonging to eight sections, was investigated under LM and SEM. Four new exine patterns were found in the species: a) microcchinate-foveolate, b) rugulate, c) verrucate-perforate, and d) verrucaterugulate ornamentation. In addition, two patterns, the Rheum-type pollens with microechinate-perforate and fine-reticulate, as previously described, were also confirmed in the present study. Based on above study the evolution trends of pollen morphology in the taxa involved were discussed phylogenetically as below. As microechinate-perforate exine pattern existed commonly, the pattern is, therefore, regarded as the most primitive among all the six types. The fine-reticulate type was thought as a derivative type, deriving from the basic micro echinate-foveolate-perforate pattern, and followed by the rugulate and verrucate-perforate ornamentation. The verrucate-rugulate ornamentation should be the most advanced. More than one pollen type often exist in most of the sections in Rheum. The pollen morphology of Rheum was strongly correlated with its geographical and ecological distribution. Three medicinally important species R. officinale, R. palmation and R. tanguticum can be palynologically distinguished by their ornamentations.

Molecular phylogeny, recent radiation and evolution of gross morphology of the rhubarb genus Rheum (Polygonaceae) inferred from chloroplast DNA trnL-F sequences

Background and Aims Rheum, a highly diversified genus with about 60 species, is mainly confined to the mountainous and desert regions of the Qinghai-Tibetan plateau and adjacent areas. This genus represents a good example of the extensive diversification of the temperate genera in the Qinghai-Tibetan plateau, in which the forces to drive diversification remain unknown. To date, the infrageneric classification of Rheum has been mainly based on morphological characters. However, it may have been subject to convergent evolution under habitat pressure, and the systematic position of some sections are unclear, especially Sect. Globulosa, which has globular inflorescences, and Sect. Nobilia, which has semi-translucent bracts. Recent palynological research has found substantial contradictions between exine patterns and the current classification of Rheum. Two specific objectives of this research were (1) to evaluate possible relationships of some ambiguous sections with a unique morphology, and (2) to examine possible occurrence of the radiative speciation with low genetic divergence across the total genus and the correlation between the extensive diversification time of Rheum and past geographical events, especially the recent large-scale uplifts of the Qinghai-Tibetan Plateau.Methods The chloroplast DNA trnL-F region of 29 individuals representing 26 species of Rheum, belonging to seven out of eight sections, was sequenced and compared. The phylogenetic relationships were further constructed based on the sequences obtained.Key Results Despite the highly diversified morphology, the genetic variation in this DNA fragment is relatively low. The molecular phylogeny is highly inconsistent with gross morphology, pollen exine patterns and traditional classifications, except for identifying all samples of Sect. Palmata, three species of Sect. Spiciformia and a few species of Sect. Rheum as corresponding monophyletic groups. The monotypic Sect. Globulosa showed a tentative position within the clade comprising five species of Sect. Rheum. All of the analyses revealed the paraphyly of R. nobile and R. alexandrae, the only two species of Sect. Nobilia circumscribed by the possession of large bracts. The crude calibration of lineages based on trnL-F sequence differentiation implied an extensive diversification of Rheum within approx. 7 million years.Conclusions Based on these results, it is suggested that the rich geological and ecological diversity caused by the recent large-scale uplifts of the Qinghai-Tibetan Plateau since the late Tertiary, coupled with the oscillating climate of the Quaternary stage, might have promoted rapid speciation in small and isolated populations, as well as allowing the fixation of unique or rare morphological characters in Rheum. Such a rapid radiation, combined with introgressive hybridization and reticulate evolution, may have caused the transfer of cpDNA haplotypes between morphologically dissimilar species, and might account for the inconsistency between morphological classification and molecular phylogeny reported here.

青藏高原毛茛科3种特有植物核型和进化研究

对青藏高原高山冰缘地区毛茛科3 种特有植物的核型进行了分析。它们的核型公式(K)、染色体相对长度组成(C. R. L. ) 和核型不对称系数(A s. K% ) 分别为: 青藏金莲花 T rollius pumilus var. tangu ticus: K (2n) = 6m + 8sm (2SA T ) + 2st, C. R. L. = 4L + 4M 2+ 4M 1+ 4S,A s. K% = 63. 57, 核型属2B型; 甘青乌头A conitum tanguticum 为K (2n) = 6m + 10sm ,C. R. L. = 4L + 8M 1+ 4S,A s. K% = 62. 54, 2B 型; 单花翠雀花Delphinium candelabrum var.monanthum 为K (2n) = 6m + 8sm + 2st, C. R. L. = 4L + 4M 2+ 4M 1+ 6S,A s. K% = 64. 34, 属3B 型。经同相关近缘种核型资料比较, 青藏金莲花核型不对称性和进化程度比金莲花T.ch inensis 低; 甘青乌头的核型不对称性和进化程度在其近缘类群(乌头组Sect. Aconitum ) 已报道的种之内最低; 单花翠雀花核型不对称性和进化水平比翠雀组(Sect. Delphinastrum ) 已报道的展毛翠雀花D. kamaoense var. glabrescens、多枝翠雀花D. maxim owiczii 和蓝翠雀花D. caeruleum 都低。这与该3 种植物在王文采先生(1979) 中国毛茛分类系统中的位置是一致的。

A molecular marker that is specific to medicinal rhubarb based on chloroplast trnL/trnF sequences

"Da-Huang" (Radix et Rhizoma Rhei, medicinal rhubarb), a famous and important Traditional Chinese Medicine, has often been confused with the adulterant species in the same genus, Rheum. Through sequencing the trnL (UAA)/trnF (GAA) regions of chloroplast DNA of thirteen species of Rheum (three medicinal rhubarb species and ten adulterant ones), a molecular marker of the medicinal species was found. A pair of PCR primers based on the sequences, was thus designed, which amplified a highly specific DNA fragment in medicinal rhubarb exclusively, and absent in the adulterants at all under an optimized PCR condition.