Table of Contents
  • Volume 51 Issue 4

    Cover illustration: Maps show spatial richness patterns of vascular plants on Qinghai-Tibetan Plateau. HR, richness of herbaceous plants; WR, richness of woody plants; SR, richness of species; GR, richness of genus; FR, richness of family; WP, proportion of woody plants in all vascular plants. Photos are all taken by Ling-Feng MAO on Qinghai-Tibetan Plateau. See MAO et al., pp. 371–381 in this issue.
      
      Research Articles
    • Ling-Feng MAO, Sheng-Bin CHEN, Jin-Long ZHANG, Yan-Hui HOU,Guang-Sheng ZHOU, Xin-Shi ZHANG
      2013, 51 (4): 371–381
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      The Qinghai–Tibetan Plateau (QTP), known as “the Roof of the World”, is one of the most unique and vulnerable biodiversity regions on Earth. However, the spatial patterns and determinants of vascular plant diversity on the QTP are still poorly documented, despite a number of publications focusing on its flora. Using extensively compiled data gathered from local flora and specimen records, we evaluated the relative importance of water, energy, and habitat heterogeneity-related variables in shaping the distribution of vascular plant diversity (species, genus, family, herb, woody plants). We found that higher richness always occurred in the south and east of the QTP, especially along the Himalayas, and that habitat heterogeneity, water, and energy variables are important determinants of vascular plant richness patterns on the QTP. The explanatory power of most single predictors was obviously different across life forms, with woody plant richness generally more sensitive to most environmental factors than herb richness. In addition, the explanatory power of habitat heterogeneity models, combined water and energy models, and environmental models increased as the taxonomic level increased from species to family. The results highlight that correlations between plant richness and environmental variables vary with life form and taxonomic scale, and suggest that the explanatory power of variables will change in different spatial scales due to the proportion of life forms and the asymmetric effects of these drivers on life form richness.
    • Cai ZHAO, Xiang-Guang MA, Qian-Long LIANG, Chang-Bao WANG, Xing-Jin HE
      2013, 51 (4): 382–395
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      To obtain a better understanding of how Quaternary climatic oscillations influenced range distributions and intraspecific split of alpine plants on the Qinghai–Tibetan Plateau (QTP) and in adjacent regions, we investigated the extant phylogeographical structure of Bupleurum smithii in this area based on 22 populations and 103 individuals spanning the entire distribution region of this species using chloroplast DNA sequences. Two major haplotype lineages were identified, and at least two corresponding glacial refugia maintaining in the northeastern and eastern edge of the QTP during the Last Glacial Maximum were revealed. Secondary contact between populations and efficient gene flow were also found between two major haplotype lineages. In addition, based on the geographic distribution of haplotypes, we found that populations on the platform derived from individuals that recolonized this area from refugia situated at the northeastern and eastern edges of the QTP, and that B. smithii recolonized from southern to northern China during inter- and post-glacial periods.
    • Mi-Mi LI,Jian-Hua LI
      2013, 51 (4): 396–404
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      Despite several morphological and molecular analyses of Theaceae, several outstanding issues remain in the phylogenetics and biogeography of the family including the disputed relationships among the tribes Gordonieae, Stewartieae, and Theeae, the controversial taxonomic status of Hartia and Stewartia, and the unclear biogeographic history of Gordonieae and Stewartieae. In this study we gathered DNA sequences of multiple plastid genes from 27 species of Theaceae representing all genera except Laplacea, conducted phylogenetic analyses using parsimony, likelihood, and Bayesian methods, and estimated divergence times within a Bayesian framework with fossil calibrations and molecular data. Our data provided further support for the three tribes in the family and for the sister-group relationship of Theeae to Stewartieae plus Gordonieae. Within Gordonieae, our study for the first time offered strong molecular support for the sister relationship of Franklinia and Schima. Within Stewartieae, our data supported the paraphyly of Stewartia including Hartia. Within Stewartia, our data for the first time suggested that North American (NA) species Stewartia ovata was more closely related to eastern Asian (EA) species than to the other NA species Stewartia malacodendron. Biogeographic analyses indicated that disjunct endemic species of Gordonieae might have originated from NA and those of Stewartieae from EA. Divergence times of the EA-NA disjunct pairs identified in this study (Franklinia and Schima in Gordonieae and S. ovata (NA) and Asian species of Stewartia) were estimated to be in the Mid-Miocene. Population exchanges in Gordonieae and Stewartieae may have occurred over the Bering land bridge prior to the Mid-Miocene.
    • Shi-Guo SUN, Chi-Yuan YAO
      2013, 51 (4): 405–412
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      Flower orientation has been considered one aspect of floral attraction. Plants growing on slopes should orientate their flowers facing down slope towards greater open space to enhance reproduction by attracting more pollinators. Flower angle and floral symmetry may affect this pattern; for example, this trend would be overshadowed in vertical/pendent flowers with radial symmetry because the flowers can attract pollinators and provide landing platforms from many directions. We investigated this hypothesis in Lilium duchartrei, a herb with pendent and actinomorphic flowers, in the Hengduan Mountains region of China by measuring flower direction for individuals growing on flat ground and on slopes. We also changed flower direction from facing down to up slope to test the effects on pollinator visitation frequency and subsequent plant reproduction. Plants growing on flat ground orientate their flowers equally towards the four geomagnetic directions, whereas the flowers on individuals growing on slopes preferentially face down slope. This pattern was more pronounced for individuals growing on steeper slopes. There was a positive correlation between slope angle and the seed set of flowers facing down slope (control), but a negative correlation between seed set and flowers facing up slope. The visitation frequency also tended to be higher for control flowers on steeper slopes and lower for those flowers changed to face up slope. Unexpectedly, floral direction was not affected by flower angle or floral symmetry. The results suggest that a down slope orientation of flowers could function to improve pollination in heterogeneous pollination environments.
    • Su-Ping LI, Ya-Qin HU, David Kay FERGUSON, Jian-Xin YAO, Cheng-Sen LI
      2013, 51 (4): 413–425
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      Palynological analysis of 24 samples from four types of natural pollen traps (Lugu Lake bottom sediments, surface soil, bark samples, and moss cushions) in four sites at different altitudes from the Lugu Lake area, southwest China, has been undertaken to investigate pollen dispersal and deposition in a mountainous area and assist with the interpretation of fossil pollen analysis. Detailed comparisons between the palynological assemblage and the modern vegetation in the Lugu Lake region have been carried out. Preliminary interpretations of the correlation between pollen assemblage and vegetation at the different vertical vegetational zones can be recognized by the percentages of the main taxa, and most of the pollen taxa except Pinus are expected to be underrepresented. Exotic pollen grains can be transported over mountains more than 70 km away by wind. Upslope or downslope transport of pollen grains is crucial when reconstructing palaeoclimate in mountainous areas. We summarize the altitudinal distributions of modern woody plants whose pollen grains are present at three sites, and reveal that pollen grains are more readily carried uphill than downhill. These findings have important implications regarding the reconstruction of vegetation in mountainous regions and the interpretion of palaeoelevations.

    • Li-Jun YAN, Lian-Ming GAO, De-Zhu LI
      2013, 51 (4): 426–434
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      Rhododendron×duclouxii is morphologically intermediate between Rhododendron spiciferum and Rhododendron spinuliferum, and was suspected to be a natural hybrid between these species. In this study, the nuclear ribosomal internal transcribed spacer (ITS) and chloroplast trnL-F regions of 34 accessions of R. ×duclouxii and its putative parents were analyzed for evidence of hybridization. The results from molecular data supported by morphology demonstrated that R. ×duclouxii represents a natural hybrid between R. spiciferum and R. spinuliferum. It also implies that the hybridization between R. spiciferum and R. spinuliferum is bidirectional, and that populations of R. ×duclouxii represent hybrid swarms from backcrossing or selfing of F1 plants. The study is important for understanding the speciation processes in the genus since it demonstrates for the first time the existence of a natural homoploid hybrid in Rhododendron subgenus Rhododendron.
    • Wen-Bin YU, Jie CAI, De-Zhu LI, Robert R. MILL, Hong WANG
      2013, 51 (4): 435–450
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      Pedicularis shows high diversity in its corolla form, however, its floral ontogeny has been rarely investigated. In particular, the development of the highly variable upper lip (galea), three broad morphological types of which (beakless and toothless, beakless and toothed, beaked) can be discriminated, remains unknown. We used scanning electron microscopy to investigate the early stages of floral ontogeny in two beaked species, Pedicularis gruina and P. siphonantha. To compare the developmental processes of the three galea types, three species for each type were investigated. Initiations of floral organs in Pedicularis are consistent. Sepal initiations are successive from the lateral-adaxial primordia, followed by the lateral-abaxial ones (these sometimes missing), then the mid-adaxial one (again sometimes missing). The stamens are initiated prior to the petals, or development of petal primordia may be retarded at the early stages in comparison with that of stamen primordia. Four stamen primordia are initiated simultaneously. The five petal primordia are initiated almost simultaneously. Development processes of the upper lip among the three galea types differ in the expansion rates and directions of the cells of the two lobes and these differences govern whether or not a beak and/or teeth are formed on the upper lip. The floral ontogeny of Pedicularis is close to that of Agalinis, which supports the molecular assignment. Floral monosymmetry of Pedicularis is established at the beginning of sepal initiation and is maintained until flowering. The development of the upper lip provides some clues to the evolution of beaked and/or toothed galeas in Pedicularis.
    • Lua LOPEZ, Rodolfo BARREIRO
      2013, 51 (4): 451–460
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      A previous study with amplified fragment length polymorphism (AFLP) fingerprints found no evidence of genetic impoverishment in the endangered Centaurea borjae and recommended that four management units (MUs) should be designated. Nevertheless, the high ploidy (6x) of this narrow endemic plant suggested that these conclusions should be validated by independent evidence derived from non-nuclear markers. Here, the variable trnT-F region of the plastid genome was sequenced to obtain this new evidence and to provide an historical background for the current genetic structure. Plastid sequences revealed little genetic variation; calling into question the previous conclusion that C. borjae does not undergo genetic impoverishment. By contrast, the conclusion that gene flow must be low was reinforced by the strong genetic differentiation detected among populations using plastid sequences (global FST = 0.419). The spatial arrangement of haplotypes and diversity indicate that the populations currently located at the center of the species range are probable sites of long-persistence whereas the remaining sites may have derived from a latter colonization. From a conservation perspective, four populations contributed most to the allelic richness of the plastid genome of the species and should be given priority. Combined with previous AFLP results, these new data recommended that five, instead of four, MUs should be established. Altogether, our study highlights the benefits of combining markers with different modes of inheritance to design accurate conservation guidelines and to obtain clues on the evolutionary processes behind the present-day genetic structures.

    • Fan LIU, Xiao-lin ZHANG, Qing-feng WANG, Hui LIU, Guang-Xi WANG, Wei Li
      2013, 51 (4): 461–467
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      Resource allocation, as well as the tradeoffs among different reproductive components, plays an important role in the adaptability of plants to different environments. The hybrid may exhibit a higher adaptability in life history in heterogeneous environments because of the genetic variation derived from its parents. In this study, we exploited three levels of water depths and two types of sediments to investigate the resource allocation pattern of the first generation of the natural hybrid Potamogeton ×intortifolius compared to its parents P. wrightii and P. perfoliatus. We also measured the ramet survivorship and the seed set of the hybrid P. ×intortifolius. Our results showed that P. ×intortifolius had higher ramet survival than its parents at 1.5-m water depth on clay sediment. The possible tradeoffs showed that in P. ×intortifolius the tradeoff pattern between sexual and clonal reproduction was more pronounced in limiting environments. The individuals allocated more resources to sexual reproduction when the environment was limiting, which might confer a higher ability to utilize resources, to produce offspring and to found new populations. Although the seed set of P. ×intortifolius was lower than its parents, it had a higher ability to increase its seed set when the environment was limiting (sandy sediment) than its parents, which might benefit its future survival. These results indicated that the F1 hybrid P. ×intortifolius was more able to adapt to limiting environments than one or both of its two parental taxa.

    • Wen YE,Yu-Mei WEI,Alfons SCHÄFER-VERWIMP,Rui-Liang ZHU
      2013, 51 (4): 468–475
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      The systematic position of the small neotropical genus Oryzolejeunea (three spp.) has long been controversial. Phylogenetic analyses of molecular data for the present study using DNA markers (trnL, psbA, and a nuclear ribosomal internal transcribed spacer [nrITS] region) shows that the genus is nested in Lejeunea. The results not only reveal the phylogenetic position of Oryzolejeunea for the first time, but also challenge the taxonomic value of the proximal hyaline papilla as a key feature in Lejeunea. The present study shows the urgent need for a reassessment of the perimeters of the genus Lejeunea and its infrageneric classification. Three new combinations, namely Lejeunea saccatiloba, Lejeunea grolleana, and Lejeunea venezuelana, are proposed.

    • Lira GAYSINA, Yvonne NĚMCOVÁ, Pavel ŠKALOUD, Tereza ŠEVČÍKOVÁ, Marek ELIÁŠ
      2013, 51 (4): 476–484
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      Soil hosts diverse communities of photosynthetic eukaryotes (algae) that have not yet been fully explored. Here we describe an interesting coccoid green alga isolated from a soil sample from a forest-steppe in South Urals (Bashkortostan, Russia) that, based on a phylogenetic analysis of 18S rRNA gene sequence, appears to represent a new phylogenetic lineage related to the genus Leptosira within the class Trebouxiophyceae. This new alga is characterized by uninucleate cells with a shape ranging from spherical to ellipsoid or egg-like, occurring solitary or more often grouped in irregular masses or colonies. Remarkably, cells with a characteristic pyriform shape are encountered in cultures grown on a solid medium. The cells harbour a single pyrenoid-lacking parietal chloroplast with the margin undulated or forming finger-like projections; in mature cells the chloroplast becomes divided by deep incisions into more or less separate lobes. Transmission electron microscopy of vegetative cells revealed an unprecedented structure in the form of a cluster of microfibrils located in the cytoplasm near the plasma membrane, often appressed to the chloroplast. Reproduction takes place via autospores or biflagellated zoospores. The unique suite of characters of our isolate distinguishes it from previously described coccoid green algae and suggests that it should be classified as a new species in a new genus; we propose it be named Chloropyrula uraliensis.

    • Xue-Ping Wei, Xian-Chun Zhang
      2013, 51 (4): 485–496
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      The species delimitation of Lemmaphyllum, including the former segregated Lepidogrammitis in China, was considered as unresolved. Previous treatments accepted between one and 20 species. In the present study, multivariate analysis and maximum parsimony analyses were carried out on data from herbarium specimens of this genus by evaluating 24 quantitative characters and 13 qualitative characters. In total, 558 specimens representing 11 previously accepted species and one variety in China were studied. As a result, three species and two varieties were recognized, Lemmaphyllum pyriforme, L. rostratum, L. carnosum, L. carnosum var. microphyllum, and L. carnosum var. drymoglossoides. Two new combinations and seven new synonyms were introduced. An identification key and distribution maps were provided. This study also elucidated the diagnostic value of two previously ignored characters, scales at the base of stipe and laminae hydathodes.
    • 2013, 51 (4): 497–497
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Editors-in-Chief
Song Ge
Jun Wen
Impact Factor
3.7
JCR 2022 IF ranking: 60/238 (Plant Sciences, top 25%, Q2 quartile)
Journal Abbreviation: J Syst Evol
ISSN: 1674-4918 (Print)
1759-6831 (Online)
CN: 11-5779/Q
Frequency: Bi-monthly

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