Systematics of the Genus Cyananthus Wall. ex Royle

The genus Cyananthus is distributed in the Himalayan Floristic Subregion. In the early years, it was treated as a member of Polemoniaceae, but it is now generally regarded as a natural group of Campanulaceae. Made in this paper were a comprehensive comparative morphological study, a biometrical analysis of quantitative characters and an analysis of distribution pattern. The systematic position of the genus is discussed based on the evidence from pollen morphology, chromosome number and external morphology. Finally the classification of the genus is revised. As a result of the character analysis, the evolutionary trends of the characters in Campanulaceae are suggested: superior ovary is a primitive state; the pollen grains have evolved from long-multicolpal to short-colpal, then to multiporate; the basic chromosome numbers have changed from 7 to 8 or 9, from which the groups with x=17 are derived (see Fig. 2), Fig. 2 illustrates that Cyananthus is the most primitive genus in the Gampanulaceae, closely related to Codonopsis, Platycodon, Leptocodon and Campanumoea. All these genera are relatively primitive in the family. The genus Cyananthus is distributed in S. E. Gansu (Zhugqu), W. Sichuan, S. and E. Xizang, S. Qinghai and N. W. Yunnan, extending westwards to Kashmir along the Himalayas. Therefore, the genus is strictly limited to the Hengduan Mountains and the Himalayas. That is to say, it occupies the whole Sino-Himalayan Floristic Subregion (Fig. 3). This is of great importance for determining the limits of the floristic subregion, and for drawing a more acurate line between the Sino-Japanese Subregion and the Sine-Himalayan Floristic Subregion. The analysis of distribution patterns of species shows that the Hengduan Mountains is the distribution centre of the two major groups of Cyananthus, Sect. Stenolobi Franch. and Sect. Annui (Lian) Hong et L. M. Ma. In these two groups, only four out of 12 species, i. e. C. incanus Hook. f. et Thoms., C. macrocalyx Franch., C. hookeri C. B. Cl. and C. inflatus Hook. f. et Thoms., extend their areas westwards to Sikkim and Nepal. The other section, Sect. Cyananthus also exists in the west of the Hengduan Mountains. Although in the Himalayas occur three major groups of the genus, only the last-mentioned group-Sect. Cyananthus is mainly distributed in the area (Fig. 4). According to the fact, we tend to infer that the Hengduan Mountains is both the frequency and diversity centers of the genus Cyananthus. The genera of Campanulaceae, which are relatively primitive and the closest relatives of Cyananthus, all occur in SW China and the adjacent regions. Therefore, the region may well be the preserved center of the primitive genera, or even may be the original center of the Campanulaceae. All data accumulated demonstrate that the genus is very old but still under intensive differentiation. With few diagnostic qualitative characters, the characters used in classifications are mostly quantitative ones. The following characters were usually used for classification of the genus: habit, plant size, leaf shape, leaf size, hairs on the leaf, corolla colour, petiole length, corolla length and hairs on the calyx, etc. Among them, only habit, corolla colour and hairs belong to qualitative characters, and all of the others are quantitative ones. Because variation ranges of quantitative characters have never been thoroughly studied in the previous classifications, some named taxa are artificial. An extensive statistical analysis of quantitative characters were carried out in the work to reveal their variation ranges. Based on this, 5 specific names are reduced as synonyms: C. microrhombeus C. Y. Wu is reduced to C. delavayi Franch.; C. argenteus Marq. to C. longiflorus Franch.; C. pseudo-inflatus Tsoong to C. inflatus Hook. f. et Thoms.; and both C. neurocalyx C. Y. Wu and C. leiocalyx (Franch.) Cowan to C. macrocalyx Franch., while C. montanus C. Y. Wu and C. Petiolatus Franch. are treated as subspecies in C. flavus Marq. and C. incanus Hook. f. et Thoms. respectively. As a result of the revision, 19 species and 2 subspecies are recognized in the present paper, with 7 species names and 15 variety names reduced. The genus is divided into three sections according to habit, corolla lobes and hairy types on calyx: Sect. Cyananthus, Sect. Stenolobi Franch. and Sect. Annui (Lian) Hong et L. M. Ma. In the present paper the chromosome number of the genus Cyananthus is reported for the first time, C. inflatus Hook. f. et Thoms. from Yadong, S. Tibet, being found to have 2n=14. And pollen morphology of the genus Leptocodon was first examined under SEM and is shownin Plate 1.     

Identification of Tinospora cordifolia (Willd.) Miers ex Hook F & Thomas using RAPD markers

Identified germplasm is an important component for efficient and effective management of plant genetic resources. Traditionally, plant identification has relied on morphological characters like growth habit, floral morphology like flower colour and other characteristics of the plant. Studies were undertaken for identification and genetic variation within 15 clones of Tinospora cordifolia through random amplified polymorphic DNA (RAPD) markers. Analysis was made using forty decamer primers. Out of them, 15 primers were selected and used for identification and genetic relationships within 15 clones. A total of 138 distinct DNA fragments ranging from 0.2 to 3.2 kb were amplified using 15 selected random primers. The genetic similarity was evaluated on the basis of presence or absence of bands. The genetic distance was very close within the clones. Thus, these RAPD markers have the potential for identification of species and characterization of genetic variation within the population. This study will be helpful to know the genetic background of the medicinal plants with high commercial value, and also provides a major input into conservation biology.     

Selective light transmittance of translucent bracts in the Himalayan giant glasshouse plant Rheum nobile Hook. f. & Thomson (Polygonaceae)

Translucent bract transmittance of ultraviolet (UV) to infrared (IR) radiation (between 320 and 800 nm) and leaf anatomy were examined in a glasshouse plant, Rheum nobile Hook. f. & Thomson (Polygonaceae) to assess the function of avoiding injury by UV radiation while keeping the inflorescence warm by photosynthetically active (PA) and IR radiation. Although the translucent bracts and rosulate leaves transmitted little UV radiation, the former always transmit more PA and IR radiation. Additionally, the bracts transmit much more scattered solar radiation than direct radiation. The bracts are also anatomically different from the rosulate leaves. They have two or three layers of mesophyll cells with neither palisade nor spongy parenchymatous cells; in addition, the uppermost layer of mesophyll and the epidermis stain easily, and both are thought to play a role in attenuating UV radiation. The leaf epidermis of many land plants has UV absorbing pigments such as flavonoids, which absorb almost all UV radiation. Thus the role of the bracts of R. nobile is to protect the reproductive organs by absorbing UV radiation and to keep them warm by transmitting PA and IR radiation. The bracts are believed to have adapted function and form to the environment, in particular, to the weather conditions of the eastern Himalaya.     

唇冠芒毛苣苔--中国芒毛苣苔属一新记录种

唇冠芒毛苣苔Aeschynanthus hildebrandii Hemsl. ex Hook. f. 在中国首次记录.     

唇冠芒毛苣苔——中国芒毛苣苔属一新记录种

唇冠芒毛苣苔 Aeschynanthus hildebrandii Hemsl.ex Hook.f.在中国首次记录。     

Insect Pollination in the Cycad Genus Bowenia Hook, ex Hook. f. (Stangeriaceae)1

All confirmed records of entomophilic pollination in cycads are for species in the Zamiaceae. This paper presents details of entomophily in both species of Bowenia in the Stangeriaceae. Seed set in female cones from which wind and water‐borne pollen, but not insects, was excluded, indicates that pollination is obligately entomophilous. The pollination vectors are Miltotranes weevils and the relationships are species‐specific and possibly coevolutionary.     

Habitat distribution modeling of endangered medicinal plant Picrorhiza kurroa (Royle ex Benth) under climate change scenarios in Uttarakhand Himalaya,India

Climate change has been the key factor in changing the alpine vegetation's habitat and causing it to migrate to higher latitudes. The present study aims to model the current and future potential habitat distribution of endangered medicinal plant Picrorhiza kurroa Royle ex Benth in Uttarakhand Himalaya using the maximum entropy (MaxEnt) modeling. We initially select twenty-two environmental variables (bioclimatic + topographic) got from the Fifty-four (54) species occurrence points, which were further reduced to nine variables to prevent multicollinearity. Shared Socioeconomic Pathways (SSP1–2.6 and SSP2–4.5) from the CMIP6 (BCC-CSM2-MR) climate model for the periods 2041–60 and 2061–80 were used to predict the current and future habitat distribution of P. kurroa. Results showed that the precipitation of the driest month (Bio 14; 33.8%), isothermality (Bio 3; 20.2%), mean temperature of warmest quarter (Bio 10; 12.7%), and temperature annual range (Bio 7; 12.2%) were the important bioclimatic variables influencing the habitat of P. kurroa. Overall, there is a decrease in the habitat of P. kurroa under climate change scenarios. The present results may prove insightful for the decision-makers to identify suitable sites in the wild for the further propagation of P. kurroa.     

Evaluation of anthraquinones from Himalayan rhubarb (Rheum emodi Wall. ex Meissn.) as antiproliferative agents

Rheum emodi (Polygonaceae), a multipurpose medicinal herb is a rich repository of pharmacologically active secondary metabolites known as anthraquinones. The present study entails HPLC quantitation and in vitro activity of four major constituents and the extracts of R. emodi. The anthraquinone glycosides were more abundant than their aglycone constituents viz. emodin and chrysophanol. MTT assay was used to assess the in vitro antiproliferative activity of anthraquinones and extracts on four cancer cell lines namely MIAPaCa-2, HCT-116, MCF-7 and T47D. The cytotoxicity was more obvious on MIAPaCa-2. Further, the study of mechanism of action involving cell cycle analysis and determination of mitochondrial membrane potential (MMP) loss was also investigated. The extracts significantly reduced cell viability by inducing apoptosis/necrosis and cell cycle arrest with concurrent loss of MMP (∆ψm) in a concentration dependent manner. The methanolic extract of rhizome (SPL5) with the least IC₅₀ value (25 μg/ml) showed a significant increase in the percentage of apoptotic/necrotic cells (42.3% at 100 μg/ml) compared to that of vehicle treated cells (11.6%). These cellular manifestations corresponded remarkably with a decrease in the integrity of the mitochondrial membrane. In conclusion, SPL5 with emodin and chrysophanol as the preponderant constituents exhibited considerable antiproliferative activity possibly by reducing cell viability and stirring up ∆ψm loss.     

桃儿七种子休眠解除过程中细胞壁代谢及种皮超微结构的变化北大核心CSCD

为探究低温层积过程中桃儿七种子细胞壁代谢及种皮超微结构与休眠解除的内在联系,该研究通过低温层积解除桃儿七种子休眠,分析休眠解除过程中种子不同部位细胞壁组分及相关代谢酶的变化,同时利用扫描电镜对种皮的超微结构进行观察。结果表明,(1)桃儿七种皮主要由角质层、栅状石细胞层及海绵组织层3层构成,在层积过程中,种皮内部的海绵组织逐步疏松膨胀,种皮表面破损加剧;(2)种子不同部位的细胞壁组分具有明显差异,整个层积过程中,种胚、种皮和胚乳中的纤维素含量均在层积中期(45 d和60 d)降至最低,3个部位的纤维素酶活性在层积中期对应升高;种胚和种皮内的半纤维素含量均在层积中期显著下降,种皮中甘露聚糖酶活性和木糖苷酶活性在层积中期时相应达到最大;3个部位的果胶含量均在层积后期(75 d和90 d)时显著下降,而种皮和胚乳中多聚半乳糖醛缩酶活性也在层积后期相应升高;(3)种胚和胚乳内过氧化物酶活性在层积75 d和90 d时明显下降,而SOD活性在此时显著上升。(4)种子不同部位3种木质素单体的组成比例具有明显区别,同时3种木质素单体含量均随层积时间的延长而显著降低,且胚乳和种皮中的S-木质素含量对种子萌发存在显著的负向影响关系。研究认为,在低温层积过程中,桃儿七种子内细胞壁组分纤维素、半纤维素及木质素的逐步酶解,活性氧作用下的细胞壁松弛以及海绵组织层的疏松膨胀和种皮的破裂,破坏了细胞壁的刚性结构,促使种子机械束缚力降低,吸水性能提高、胚根生长能力增强,最终导致其休眠解除。     

Heteroscyphus fissistipus (Hook.f. & Taylor) Schiffn. established in south-west Ireland,new to the Northern Hemisphere

Abstract

Heteroscyphus fissistipus (Hook.f. & Taylor) Schiffn. is reported from Garinish Island in south-west Ireland, new to the Northern Hemisphere. Material collected in 1999 is described and illustrated. Male and female plants are present in pure and mixed patches, and evidence for sporophyte production was observed. H. fissistipus has probably reached Ireland from introduced horticultural sources of antipodean origin.     

Labellar anatomy and secretion in Bulbophyllum Thouars (Orchidaceae: Bulbophyllinae) sect. Racemosae Benth. & Hook. f.

Background and Aims

Floral secretions are common in Bulbophyllum Thouars, and the labella of a number of Asian species are said to produce secretions rich in lipids that act as food rewards for insect pollinators. Although some of these reports are based on simple histochemical tests, a much greater number are anecdotal and, hitherto, neither the ultrastructure of the labellum nor the secretory process has been investigated in detail. Furthermore, sophisticated histochemical approaches have generally not been applied. Here, both the labellar structure and the secretory process are investigated for four species of Asian Bulbophyllum sect. Racemosae Benth. & Hook. f., namely Bulbophyllum careyanum (Hook.) Spreng., B. morphologorum Kraenzl., B. orientale Seidenf. and B. wangkaense Seidenf., and compared with those of unequivocal lipid-secreting orchids.

Methods

Labellar, secretory tissue was investigated using light microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry.

Key Results

The adaxial median longitudinal groove of the labellum contained secretory tissue comprising palisade-like epidermal cells, similar to those of certain lipid-secreting Oncidiinae Benth. However, these cells and their secretions gave positive results mainly for protein and mucilage, and their organelle complement was consistent with that of cells involved in protein and mucilage synthesis. Sub-cuticular accumulation of secretion resulted in cuticular distension and blistering. The sub-epidermal layer of isodiametric parenchyma contained starch and, like the epidermal cells, ultrastructure consistent with mucilage synthesis. Lipids were mainly confined to the cuticle, and hardly any intracellular lipid droplets were observed.

Conclusions

It is proposed that mucilage is produced by dictyosomes present in the palisade-like epidermal cells. Mucilage precursors may also be produced by these same organelles in sub-epidermal cells and are thought to pass along the symplast via plasmodesmata into the adjoining palisade-like secretory cells, which contain abundant arrays of rough endoplasmic reticulum. Here, they become chemically modified and form a protein-rich, mucilaginous secretion that, following vesicle-mediated transport across the cytoplasm, traverses the cell wall and accumulates in blisters formed from the distended cuticle. Rupture of these blisters releases the secretion onto the labellar surface. However, in certain species, there is some evidence that the secretion may traverse the cuticle via cuticular pores, and micro-channels may permit the passage of fragrance. Hydrolysis of sub-epidermal starch probably generates the carbohydrate and, together with mitochondria, much of the energy required for the secretory process. This anatomical organization resembles that found in certain lipid-secreting, Neotropical species of Bulbophyllum and Oncidiinae, but since the chemical composition of their secretions is different, and these taxa occur on a separate continent and have different insect pollinators, parallelism of floral anatomy is likely.     

A revision of Calvoa Hook. f. (Melastomataceae)

A revision of the genus Calvoa Hook. f. (Melastomataceae) is presented. Principal Component Analyses (PCA) and Cluster Analyses (UPGMA) were performed to elucidate three cases of difficult species delimitation and infraspecific variation, with the following results. (1) The separation between C. crassinoda Hook. f. and C. grandifolia Cogn. was clear in the results obtained with both methods. (2) The group of the West-Central African species Calvoa angolensis A. Fern. & R. Fern., C. calliantha Jacq.-Fél., C. monticola A. Chev., C. pulcherrima Gilg ex Engl., C. sapinii De Wild., C. seretii De Wild., C. sinuata Hook. f. and C. subquinquenervia De Wild, proved difficult to resolve with either analysis, but the Cluster Analysis produced results which are more consistent with the identification of the specimens. (3) Neither of the two analyses supported the recognition of infraspecific categories in Calvoa orientalis Taub. Eighteen species are recognized in the genus. The new species Calvoa Jacques-felixii E. Figueiredo is described and the new combination Calvoa seretii subsp. wildemaniana (Exell) E. Figueiredo is made. Four lectotypes are designated. The conservation status of some taxa is discussed. Six species are considered rare and possibly under threat.     

Antiulcer activity of ethanolic extract of Encholirium spectabile Mart. ex Schult & Schult f. (Bromeliaceae) in rodents

This study evaluated the antiulcer activity of an ethanolic extract of Encholirium spectabile (ES-EtOH) by using different standard experimental models of induced acute gastric ulceration. ES-EtOH (100 mg/kg p.o) protected the gastric mucosa against ulceration that was induced by absolute ethanol (53%), ethanol/HCl (75%), ibuprofen (52 %) and ischemia/reperfusion (43 %). It also restored catalase activity and non-protein sulfhydryl group concentration in the gastric wall of mice that had been treated with ethanol. The pre-treatment of mice with N-nitro-L-arginine (70 mg/kg i.p.) abolished the protective activity of ES-EtOH, which indicates that prostaglandins, antioxidant compounds and nitric oxide synthase activity are involved in the gastroprotective activity of the extract.     

Genetic Diversity and Structure of Sinopodophyllum hexandrum (Royle) Ying in the Qinling Mountains,China

Sinopodophyllum hexandrum is an important medicinal plant whose genetic diversity must be conserved because it is endangered. The Qinling Mts. are a S. hexandrum distribution area that has unique environmental features that highly affect the evolution of the species. To provide the reference data for evolutionary and conservation studies, the genetic diversity and population structure of S. hexandrum in its overall natural distribution areas in the Qinling Mts. were investigated through inter-simple sequence repeats analysis of 32 natural populations. The 11 selected primers generated a total of 135 polymorphic bands. S. hexandrum genetic diversity was low within populations (average H_e = 0.0621), but higher at the species level (H_e = 0.1434). Clear structure and high genetic differentiation among populations were detected by using the unweighted pair group method for arithmetic averages, principle coordinate analysis and Bayesian clustering. The clustering approaches supported a division of the 32 populations into three major groups, for which analysis of molecular variance confirmed significant variation (63.27%) among populations. The genetic differentiation may have been attributed to the limited gene flow (N_m = 0.3587) in the species. Isolation by distance among populations was determined by comparing genetic distance versus geographic distance by using the Mantel test. Result was insignificant (r = 0.212, P = 0.287) at 0.05, showing that their spatial pattern and geographic locations are not correlated. Given the low within-population genetic diversity, high differentiation among populations and the increasing anthropogenic pressure on the species, in situ conservation measures were recommended to preserve S. hexandrum in Qinling Mts., and other populations must be sampled to retain as much genetic diversity of the species to achieve ex situ preservation as a supplement to in situ conservation.     

Leaf architecture of the genus Didymaea Hook. f. (Rubiaceae)

We examined 532 specimens representing eight species of Didymaea (Rubiaceae) to describe their leaf architecture. Characters observed in the herbarium specimens and cleared leaves were leaf base, apex, and margin; trichome type and distribution; vein orders from primary to higher order veins, veinlets, and ultimate marginal vein. Six morphometric variables were analyzed using variance and principal component analysis to identify which characters are useful to distinguish species. Most of the species present brochidodromous venation pattern, except D. hispidula, which has eucamptodromous venation pattern; Didymaea floribunda is unique in having cylindrical and bicellular trichomes. Principal component analysis revealed that 78% of the total variation is mainly related to leaf maximum width. Variance analysis showed significant differences between D. microflosculosa and the other species. Architectural features were useful for differentiating all the species, and an identification key for the species of Didymaea based only on leaf characters is presented.