Relationships in subtribe Diocleinae (Leguminosae; Papilionoideae) inferred from internal transcribed spacer sequences from nuclear ribosomal DNA

The complete sequences of nuclear ribosomal DNA (nrDNA) internal transcribed spacer regions (ITS/5.8S) were determined for species belonging to six genera from the subtribe Diocleinae as well as for the anomalous genera Calopogonium and Pachyrhizus. Phylogenetic trees constructed by distance matrix, maximum parsimony and maximum likelihood methods showed that Calopogonium and Pachyrhizus were outside the clade Diocleinae (Canavalia, Camptosema, Cratylia, Dioclea, Cymbosema, and Galactia). This finding supports previous morphological, phytochemical, and molecular evidence that Calopogonium and Pachyrhizus do not belong to the subtribe Diocleinae. Within the true Diocleinae clade, the clustering of genera and species were congruent with morphology-based classifications, suggesting that ITS/5.8S sequences can provide enough informative sites to allow resolution below the genus level. This is the first evidence of the phylogeny of subtribe Diocleinae based on nuclear DNA sequences.     

Bibenzyls and dihydroisocoumarins from white salsify (Tragopogon porrifolius subsp. porrifolius)

A phytochemical investigation of three accessions of Tragopogon porrifolius L. subsp. porrifolius (Asteraceae, Lactuceae) yielded three new bibenzyl derivatives, 5,4'-dihydroxy-3-alpha-l-rhamnopyranosyl-(1-->3)-beta-d-xylopyranosyloxybibenzyl, 2-carboxyl-3,4'-dihydroxy-5-beta-d-xylopyranosyloxybibenzyl, tragopogonic acid (2'carboxyl-3',5',4'-trihydroxyphenylethanone) and three dihydroisocoumarin derivatives, including the new natural product 6-O-methylscorzocreticoside I. One of the isolated bibenzyl derivatives is considered to be a precursor to the biosynthesis of dihydroisocoumarins. Structures of new compounds were established by HR mass spectrometry, extensive 1D and 2D NMR spectroscopy, and CD spectroscopy. Moreover, radical scavenging activities of the polyphenolic compounds were measured using the 2,2-diphenyl-1-picrylhydrazyl assay; two of the bibenzyls showed moderate and two of the dihydroisocoumarins showed weak radical scavenging activities. The chemosystematic impact of bibenzyls and dihydroisocoumarins is discussed briefly.     

Thlaspi s.str. (Brassicaceae) versus Thlaspi s.l.: morphological and anatomical characters in the light of ITS nrDNA sequence data

 Nuclear ribosomal (ITS) DNA sequence data from representatives of eleven out of 12 genera previously included in Thlaspi sensu lato were analyzed to elucidate relationships within the former genus Thlaspi sensu lato. Sequences from Thlaspi segregates Noccaea, Masmenia, Callothlaspi, Kotschyella, Microthlaspi, and Noccidium were added to the existing data sets, and only some Thlaspi sensu lato segregates formed a monophyletic group. The recently renamed genus Pseudosempervivum, formerly part of the genus Cochlearia, has been shown to be closely related to this group as well. Microthlaspi consists of three independent lineages of which Microthlaspi umbellatum is closely related to Neurotropis. The Thlaspi s.str. taxa including the type species T. arvense, are closely related to Peltaria and Alliaria and they represent a monophyletic group. Kotschyella and Noccidium, which were also integrated into Thlaspi s.l. are not closely related to any Thlaspi lineage. Therefore, we suggest major taxonomical changes which are not in agreement with concepts based on morphological data. Our ITS based phylogeny demonstrates that subtribe Thlaspidinae comprises some additional genera such as Teesdalia, Peltaria, and Alliaria, the latter two even previously classified in other tribes than tribe Lepidieae. Received August 15, 2000 Accepted January 30, 2001     

国产唇形科香茶菜属一新记录种——暗红香茶菜

报道了采自西藏错那县的唇形科香茶菜属的一个中国新记录种,即暗红香茶菜Isodon atroruber R. A. Clement。本研究对该种进行了描述,并应用扫描电子显微镜和光学显微镜对其叶表皮、花粉及小坚果的微形态特征进行了观察和测量。此外,还编制了西藏产19种香茶菜属植物的检索表。     

Stilbenoids from Tragopogon orientalis

A phytochemical investigation of Tragopogon orientalis L. (Asteraceae, Cichorieae) yielded the natural products 6'-O-(7,8-dihydrocaffeoyl)-alpha,beta-dihydrorhaponticin, 3'-O-methyl-alpha,beta-dihydrorhaponticin, and (S)-3-(4-beta-glucopyranosyloxybenzyl)-7-hydroxy-5-methoxyphtalide as well as known compounds alpha,beta-dihydrorhaponticin, 3-(4-methoxybenzyl)-5,7-dimethoxyphthalide, p-dihydrocoumaric acid methyl ester, and 1-hydroxypinoresinol-1-O-beta-glucopyranoside. The structures were established by HR mass spectrometry, extensive 1D and 2D NMR spectroscopy, and CD spectroscopy. Moreover, the radical scavenging activities of the major compounds were measured using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The chemosystematic impact of the occurrence of stilbene derivatives in T. orientalis is discussed.     

Molecular systematics of Brassica and allied genera (Subtribe Brassicinae,Brassiceae) —chloroplast genome and cytodeme congruence

Summary Chloroplast DNA restriction sites for 20 endonucleases were mapped using cpDNA probes from Brassica juncea and site variation was surveyed in 33 diploid taxa of the Subtribe Brassicinae. A total of 419 mutations was observed, including both site (i.e., gain/ loss) and fragment length (i.e., insertions or deletions); 221 (53%) mutations showed variation at the interspecific level. Phylogenetic analysis indicated a clear division of the subtribe into two ancient evolutionary lineages. These were (I) the Nigra lineage: Brassica nigra, B. fruticulosa, B. tournefortii, Sinapis pubescens, S. alba, S. flexuosa, S. arvensis, Coincya cheiranthos, Erucastrum canariense, and Hirschfeldia incana, and (II) the Rapa/ Oleracea lineage: Brassica rapa, B. oleracea ssp. oleracea and ssp. alboglabra, B. rupestris-villosa complex (B. rupestris, B. drepanensis, B. macrocarpa, B. villosa), B. barrelieri, B. deflexa, B. oxyrrhina, B. gravinae, Diplotaxis erucoides, D. tenuifolia, Eruca sativa, Raphanus raphanistrum, R. sativus, and Sinapis aucheri. In the Nigra lineage, Brassica nigra was most closely related to the annual Sinapis species, S. arvensis and S. alba. In the Rapa/Oleracea lineage, the Brassica rapa and B. oleracea genomes formed a distinct group whose closest relatives were the wild species of the B. oleracea (n=9) complex (i.e., B. rupestris-villosa complex). Species with n=7 chromosomes exist in both lineages. Hirschfeldia incana (n=7), in the Nigra lineage, was most closely related to Sinapis pubescens. In the Rapa/Oleracea lineage three taxa with n=7 — B. deflexa, D. erucoides, and S. aucheri — were closely related, advanced in the lineage, and were the closest apparent relatives (particularly D. erucoides) to B. rapa, B. oleracea, and its wild relatives. Levels of genetic divergence suggested by the cpDNA data were consistent with cytodeme recognition in the subtribe, but provided evidence for inconsistencies in the current generic delimitations based on morphology. Very low levels of genetic divergence were evident among taxa/accessions within a cytodeme. Raphanus was closely related to the Brassica rapa and B. oleracea genomes and clearly belongs in Subtribe Brassicinae. Several cytoplasmic genetic markers of potential use in plant breeding programs were identified for each of the cytodemes.     

Phytogeny of Brassica and allied genera based on variation in chloroplast and mitochondrial DNA patterns: molecular and taxonomic classifications are incongruous

Summary Chloroplast DNA (cpDNA) variability of 60 taxa of the genus Brassica and allied genera comprising 50 species was studied. RFLPs for seven enzymes were generated and F values were estimated from five frequently cutting enzymes. Phenetic clusterings indicated a clear division of Brassica coenospecies into two distinct lineages referred to as the Brassica and Sinapis lineages. Two unexplored genera, Diplotaxis and Erucastrum, also exhibited two lineages in addition to the genera Brassica and Sinapis. This finding is inconsistent with the existing taxonomic classification based on morphology. Mitochondrial DNA (mtDNA) variability studied from EcoRI RFLP patterns, by hybridizing total DNA with four cosmid clones containing non-overlapping mtDNA fragments, did not show any congruence with cpDNA variation patterns. However, at the cytodeme level, the patterns of genetic divergence suggested by the cpDNA data could be correlated with mtDNA variation. In the Brassica lineage, Diplotaxis viminea was identified as the female parent of the allotetraploid D. muralis. The chloroplast DNAs of Erucastrum strigosum and Er. abyssinicum were found to be very closely related. In the Sinapis lineage, Brassica maurorum was found to be the diploid progenitor of autotetraploid B. cossoneana. B. amplexicaulis showed a very different cpDNA pattern from other members of the subtribe. Brassica adpressa was closest to Erucastrum laevigatum and could be the diploid progenitor of autotetraploid Er. laevigatum. Based on the close similarity of the cpDNA pattern of Diplotaxis siifolia with that of D. assurgens, we have proposed the retention of this species in the genus Diplotaxis. The taxonomic positions of some other species have also been discussed.     

Phylogenetic relationships of Thlaspi s.l. (subtribe Thlaspidinae, Lepidieae) and allied genera based on chloroplast DNA restriction-site variation

Chloroplast DNA restriction-site variation was analyzed in 30 accessions representing 20 species from the major lineages in Thlaspi s.l. (previously described as genera by Meyer 1973, 1979) and allied genera from the subtribe Thlaspidinae (Peltaria, Teesdalia, Cochlearia, Ionopsidium, Aethionema). A total of 161 variable restriction sites were detected. Phylogenetic analyses indicated a division of Thlaspi s.l. into three groups consistent with Meyer's genera Thlaspi s. str., Microthlaspi and Noccaea/Raparia. The genus Thlaspi s.l. as currently described proved to be paraphyletic because one of its major lineages, i.e. Thlaspi s. str., appeared to be more closely related to other genera (Peltaria, Teesdalia) than to the remaining lineages of Thlaspi s.l., i.e. Noccaea/Raparia and Microthlaspi. Sequence divergence values (100 x p) between the Thlaspi s.l. lineages were similar to values between these groups and related genera (Teesdalia, Peltaria), respectively. Chloroplast DNA variation was also used to assess subtribal classification of the genera studied. The cpDNA data were inconsistent with the controversial taxonomic classifications based on morphology. The molecular data would suggest that (1) the subtribe Thlaspidinae, as traditionally described, is not monophyletic; (2) the Thlaspidinae should be reduced to a group consisting of Thlaspi s. str., Peltaria, Teesdalia, Microthlaspi, Noccaea/Raparia, and that Aethionema should be excluded from the Thlaspidinae; and (3) Cochlearia and Ionopsidium represent the subtribe Cochleariinae.     

山东菊科莴苣亚族植物花粉形态研究

应用光镜和扫描电镜对山东菊科莴苣亚族11属18种、1变种植物的花粉形态进行了观察研究。结果表明:莴苣亚族植物的花粉呈球形,具3~4沟孔,花粉表面具有网状纹饰,粗网眼15~21个,网脊上具1行刺,属于蒲公英(Taraxacum)型,与已报道的莴苣亚族其它属种的花粉形态相一致。通过莴苣亚族属间花粉形态的比较,认为花粉形态在属间分类上意义不大。     

国产唇形科香茶菜属一新记录种——暗红香茶菜（英文）

报道了采自西藏错那县的唇形科香茶菜属的一个中国新记录种,即暗红香茶菜Isodon atroruber R.A.Clement。本研究对该种进行了描述,并应用扫描电子显微镜和光学显微镜对其叶表皮、花粉及小坚果的微形态特征进行了观察和测量。此外,还编制了西藏产19种香茶菜属植物的检索表。