西藏蓝钟花属一新变型——白花裂叶蓝钟花

描述了桔梗科蓝钟花属裂叶蓝钟花(Cyananthus lobatus Wall.ex Benth.)的一个新变型——白花裂叶蓝钟花(Cyananthus lobatus Wall.ex Benth.f.albiflorus J.Luo et S.L.Wang)。原变型的花冠为紫蓝色至淡蓝色,而新变型花冠为白色。     

Floral closure induced by pollination in gynodioecious Cyananthus delavayi (Campanulaceae): effects of pollen load and type, floral morph and fitness consequences

Background and aims

Pollination-induced floral changes, which have been widely documented in flowering plants, have been assumed to enhance the plant''s reproductive success. However, our understanding of the causes and consequences of these changes is still limited. Using an alpine gynodioecious species, Cyananthus delavayi, we investigated the factors affecting floral closure and estimated the fitness consequences of floral closure.

Methods

The timings of floral closure and fertilization were determined. The effects of pollen load, pollen type (cross- or self-pollen) and floral morph (female or perfect flower) on the occurrence of floral closure were examined. Ovule fertilization and seed production were examined to investigate the causes and consequences of floral closure. Flowers were manipulated to prevent closing to detect potential benefits for female fitness.

Key Results

Floral closure, which could be induced by a very low pollen load, occurred within 4–7 h after pollination, immediately following fertilization. The proportion of closed flowers was influenced by pollen load and floral morph, but not by pollen type. Floral closure was more likely to occur in flowers with a higher proportion of fertilized ovules, but there was no significant difference in seed production between closed and open flowers. Those flowers in which closure was induced by natural pollination had low fruit set and seed production. Additionally, seed production was not influenced by closing-prevented manipulation when sufficient pollen deposition was received.

Conclusions

The occurrence of floral closure may be determined by the proportion of fertilized ovules, but this response can be too sensitive to ensure sufficient pollen deposition and can, to some extent, lead to a cost in female fitness. These results implied that the control of floral receptivity by the recipient flowers does not lead to an optimal fitness gain in C. delavayi.     

中国-喜玛拉雅特有属——蓝钟花属的分类修订

Cyananthus Wallich ex Bentham, the only genus of Campanulaceae with superior ovary, is revised to clarify infrageneric relationships and phylogeny of the genus. Evidence obtained from the comparative gross morphology, anatomy, palynology, and karyomorpho-logy recommends a new infrageneric classification of the genus, recognizing 23 species, belonging to two subgenera, four sections and four subsections. One subgenus(Subgen. Mi-cranthus), one section(Sect. Suffruticulosi) and two subsections(Subsect. Flavi and Sub-sect. Lichiangenses)are described as new taxa. New combinations at sectional (Sect. Annui) and subsectional(Subsect. Stenolobi) ranks are also proposed. The genus Cyananthus is strictly distributed in the high mountains of China(Xizang, Yunnan and Sichuan), extending to Bhutan, Nepal and India (Kumaon-Garhwal, Assam and Sikkim), with altitudinal ranges from 2500 ~ 5300 m. It is observed that 13 species are endemic to SW China and only three species are endemic to the Himalayas( two species in Ne     

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.     

Systematic significance of cytology in Cyananthus (Campanulaceae) endemic to the Sino-Himalayan region

Chromosome numbers and the morphology of members of 24 populations representing 15 species of the Sino-Himalayan endemic genus Cyananthus(Campanulaceae) were studied using karyological and numerical taxonomic techniques. The chromosome numbers of these taxa are 2n = 10, 12, 14, 24, 28, and the basic chromosome numbers for the genus are x = 5, 6, 7. All species except C. inflatus Hook. f. & Thoms. and C. microphyllus Edgew. were examined for the first time and a new ploidy level (tetraploidy) is reported in the genus. Chromosome measurement data were analyzed using cluster analysis. The relationships between three sections within Cyananthus and evolutionary trends within the genus are discussed in the light of karyological data. The cytological data suggest that Cyananthus is a relatively primitive genus in Campanulaceae and there is significant division within the genus, and polyploidization may have played an important role in the chromosome evolution and speciation of Cyananthus in the Himalayan–Hengduan Mountains.     

The standing waters of Coll and Tiree in a national and international context

Summary

The aquatic vascular plants and charophytes were surveyed in a total of 200 standing waters on the Inner Hebridean islands of Coll and Tiree. A TWINSPAN classification of the sites is used to divide them into seven groups. The groups demonstrate the range of variation in the standing waters of the two islands, which in turn reflects the presence of a range of substrates from acidic peat to calcareous sand. The lake types and the rare species recorded from Coll and Tiree suggest that these standing waters are of outstanding national and international nature conservation value.