两种悬钩子属植物在中国的重新发现

报道了蔷薇科两种悬钩子属植物在中国的重新发现,分别为美叶悬钩子(Rubus calophyllus C.B.Clark)和拟针刺悬钩子(R.parapungens H.Hara),并提供了简要的描述和标本照片。     

Rubus laconensis and Rubus pignatti (Rosaceae), two new species from Sardinia (Italy)

Rubus is poorly represented in Sardinia, mainly by the widespread R. ulmifolius and further by two narrow endemic species. Two new species, R. laconensis and R. pignatti, here described and illustrated, grow in two neighbouring small areas of the Sarcidano country. Both are characterized, in particular, by fruits with a low number of large drupelets. R. laconensis is for the time being attributed to the R. caesius aggregate, and R. pignatti to R. subg. Rubus.     

DNA fingerprint variation in some blackberry species (Rubus subg.Rubus,Rosaceae)

We have analysed samples from Sweden, Denmark, and Germany of six facultatively apomictic blackberry species to investigate the accordance between a taxonomy based on morphological characters on the one hand, and distribution of genetic variation estimated by DNA fingerprinting on the other hand. DNA fingerprint variation was found to be quite restricted in all species investigated. The first taxonomic group included three species related toRubus nessensis, two being characterized by one very widespread DNA fingerprint in all three countries and a few rare ones, whereas the third species differed between Sweden and Germany. The second taxonomic group included species related toR. gracilis. Two of these species exhibited very similar DNA fingerprints, whereas the third species deviated clearly. The utilization of DNA fingerprinting as a tool in taxonomy is discussed; most likely this method could become a useful complement to morphology, especially in plant groups with reduced levels of genetic recombination.     

Photosynthetic characteristics of invasive and noninvasive species of Rubus (Rosaceae)

The prolific amount of growth and reproduction in invasive plants may be achieved by greater net photosynthesis and/or resource-use efficiency. I tested the hypotheses that leaf-level photosynthetic capacity and resource-use efficiency were greater in two invasive species of Rubus as compared with two noninvasive species that have overlapping distributions in the Pacific Northwest. The invasive species had significantly higher photosynthetic capacity and maintained net photosynthesis (A) over a longer period of the year than the noninvasive species. The construction cost (CC) of leaf tissue per unit leaf mass was comparable among the four species, but the invasive species allocated less nitrogen (N) per unit leaf mass. On a leaf area basis, both leaf CC and N were higher for the invasive species. The specific leaf area (SLA) was also lower in the invasive species, indicating less photosynthetic area per gram leaf tissue. The invasive species achieved high A at lower resource investments than the noninvasive species, including having higher maximum photosynthetic rate (A(max)) per unit dark respiration (R(d)), greater A(max) per unit leaf N (photosynthetic nitrogen-use efficiency), and greater water-use efficiency as measured by instantaneous rates of A per unit transpiration (A/E) and by integrated A/E inferred from stable carbon isotope ratios (δ(13)C). Using discriminant analysis, these photosynthetic characteristics were found to be powerful in distinguishing between the invasive and noninvasive Rubus. A(max) and A/E were identified as the most useful variables for distinguishing between the species, and therefore, may be important factors contributing to the success of these invasive species.     

Secondary metabolites of Rubus caesius (Rosaceae)

The European dewberry (Rubus caesius) is a perennial shrub that is widely distributed in Europe but can also be found in North America. In folk medicine, the European dewberry is used to treat hyperglycaemia, diarrhoea and inflammation. LC-MS analysis of the European dewberry confirmed the presence of 35 compounds, mostly flavonoids, phenolic acids and derivatives of ellagic acid. Phytochemical analysis of R. caesius leaves led to the isolation of nine phenolics, namely: quercetin 3-O-β-D-rutinoside (1), kaempferol 3-O-β-D-glucuronide (2), quercetin 3-O-β-D-glucuronide (3), methyl brevifolincarboxylate (4), kaempferol 3-O-β-D-(6″-O-(E)-p-coumaroyl)-glucoside (5), kaempferol (6), quercetin (7), pedunculagin (8), and ellagic acid (9). Compounds 1–8 were isolated from this species for the first time. The chemophenetic significance was discussed.     

Active self-pollination in blackberries (Rubus subgen. Rubus, Rosaceae)

Most blackberry species are apomictic but pseudogamous, i.e. embryo development is dependent on prior pollination. Two different types of stamen arrangement were noted in senescing flowers of 18 Swedish species and 2 common cultivars. The stamens of 'cross-pollinating' species seldom touch the stigmas while those of 'self-pollinating' species instead arch over the pistils and dry up in this position. All species set seed well after artificial self-pollination and are thus self-compatible. Isolation experiments were carried out during 3 years. When inflorescences were bagged, seed set was drastically lowered in 'cross-pollinators' but remained almost unaltered in 'self-pollinators'. The different responses to isolation are probably due to the inherent stamen behaviour.     

Apomixis versus sexuality in blackberries (Rubus subgen.Rubus,Rosaceae)

InRubus L. a connection seems to exist between the degree of meiotic disturbances on the one hand, and the production of unreduced embryo sacs, pollen fertility and relative seed set on the other hand. Severe meiotic disturbances commonly encountered in apomictic taxa decrease pollen fertility and thereby seed set since pollen is necessary for endosperm development. By contrast interspecific hybrids between apomictic taxa appear to be sexual and exhibit high pollen fertilities, probably due to an improved meiosis. Thus, apomixis leads to a decreased fertility inRubus, not the opposite, as often discussed.     

Chromosome numbers of European blackberries (Rubus subg.Rubus,Rosaceae)

Chromosome numbers are presented for 32 collections of 29 European blackberry species (Rubus subg.Rubus) from Germany. One species is triploid (2n = 21), 27 species are tetraploid, (2n = 28), and one species is pentaploid (2n = 35). Chromosome numbers are reported for the first time ofR. adspersus, R. amisiensis, R. calvus, R. conothyrsoides, R. contractipes, R. demissus, R. elegantispinosus, R. ferocior, R. foliosus, R. hypomalacus, R. leucandrus, R. nemorosus, R. platyacanthus, R. praecox, R. rhombifolius, andR. rhytidophyllus. Chromosome numbers forR. dasyphyllus, R. gelertii, R. glandithyrsos, R. lamprocaulos, R. lindebergii, R. macrophyllus, R. montanus, R. muenteri, R. pedemontanus, R. polyanthemus, R. senticosus, R. silvaticus, andR. vigorosus are confirmed.     

Genetic analysis of natural hybrids between endemic and alien Rubus (Rosaceae) species in Hawai`i

A population of putative hybrids between theendemic Rubus hawaiensis and naturalizedR. rosifolius was discovered inKpahulu Valley, on the island of Maui inthe Hawaiian archipelago. The goal of thisstudy was to molecularly characterize thisnatural hybridization event, investigate themode of hybridization, and determine the malefertility of the hybrid individuals. Bothmorphological and RAPD marker data indicatethat the putative hybrid individuals are theprogeny of R. rosifolius and R.hawaiensis. All 39 hybrid individuals sampledhad the chloroplast DNA haplotype of R.rosifolius. Thus hybridization appears to beasymmetric, with R. rosifolius acting asthe maternal parent. All hybrid individualsassessed for pollen stainability were sterile,and there was no evidence of backcrossing toeither parent. This result suggests thathybrids are of the first filial generation andthat variation among hybrids reflectsdifferences within the parental populations.Sympatric populations of R. hawaiensisand R. rosifolius occur on four islandsand six additional alien species of Rubusare naturalized and sympatric with R. hawaiensisin Hawai`i. Further investigationis merited to assess whether hybridization maypose a threat to the long term viability ofR. hawaiensis. This study highlights theincreasing frequency and negative consequencesof native-alien hybridization and theimportance of maintaining active alien speciescontrol programs in the Hawaiian Islands.     

Evidence of sexuality in European Rubus (Rosaceae) species based on AFLP and allozyme analysis

Reproduction of polyploid Rubus species is described as facultatively apomictic. Pollination is needed for seed set, but most seedlings are produced asexually by pseudogamy. Although sexual processes may occur, clonal diversity can be extremely low. We performed a pollination experiment to investigate the breeding system and used allozyme and AFLP markers to analyze genetic variation among and within seed families in R. armeniacus and R. bifrons. Pollination either with self or outcross pollen was necessary to trigger seed set. Outbreeding marginally increased the number and quality of seeds compared with selfing. The enzyme PGI revealed some genetic variation within seed families. Seven other enzyme systems were monomorphic. The more detailed AFLP analyses with five primer pairs detected the same rate of genetic variation (14-17% of seedlings were genetically distinct) and confirmed the allozyme results for the same individuals. No genetic variation was found between the seed families from within a species collected in widely separated populations, but clear species-specific differences were observed. The results support the view that polyploid Rubus species are pseudogamous apomicts with low genetic diversity among and within seed families. However, sexual reproduction occasionally occurs and contributes to the maintenance of genetic variation within natural populations.     

钻地风的三萜类成分

从钻地风根的乙醇提取物中分离得到12个三萜及三萜皂苷类化合物,通过波谱分析并与有关对照品比较, 其结构鉴定为熊果酸(1),坡模酸(2),tormentic acid (3),蔷薇酸(4),sericic acid (5),23-hydroxytormentic acid (6), kaji-ichigoside F1 (7),野蔷薇苷 (8), sericoside (9), quadranoside VIII (10), crataegioside (11)和niga-ichigoside F1 (12).初步研究结果表明,这些化合物在体外5?mg/ml浓度下对耐药金黄色葡萄球菌(MRSA)无抑制作用.     

Rubus ambrosius (Rubus subsect.Rubus, Rosaceae), a new bramble species from the eastern part of Central Europe

Rubus ambrosius Trávní?ek etOklejewicz, a widely distributed species from the eastern part of Central Europe (Czech Republic, Slovakia and Poland), is described.R. ambrosius differs from similar speciesR. sulcatus Vest by more deeply furrowed stems, longer prickles on first-year tems, longer petioles, more prickly petioles, densely hairy leaves beneath and by blunter leaf margin serration with incisions only (2-)1.5–2.5 mm deep. The newly described species is illustrated both by photographs (including the holotype) and a line drawing. A list of localities and a distribution map are presented.     

甜茶,悬钩子属一新种

本文报道蔷薇科悬钩子属的一个新种,Rubus suavissimus。 、     

Characteristics of floral nectaries and nectar in two species of Crataegus (Rosaceae)

 The structure of floral nectaries of Crataegus coccinea and C. crus-galli was examined using light and scanning electron microscopy. The radial length of the floral nectary, measured from longitudinal sections of flowers, was 30% larger in C. crus-galli than in C. coccinea. For both Crataegus species the glandular tissue thickness was similar – approx. 400 μm. Also, the number of stomata per mm² of nectary surface in C. crus-galli was much higher (by 43%) than for C. coccinea. Stomata were situated in deep hollows. For both taxa the period of nectar secretion was 4 days. The mean quantity of total sugar in nectar per 10 flowers of C. crus-galli and C. coccinea was 3.87 mg and 0.33 mg, respectively. Received August 28, 2002; accepted December 17, 2002 Published online: June 2, 2003     

Pollen stainability variation in the apomictic blackberry, Rubus nessensis (Rosaceae)

Pollen quality was assessed with cotton blue staining in an apomictic blackberry, Rubus nessensis W. Hall, on plants grown outdoors in a random arrangement under uniform conditions. Significant variation between populations may be attributed mainly to genetical factors. Most of the variation found between plants, sometimes even between ramets, within a population must, however, be environmentally caused, likewise the variation between flowers within the same plant.     

Cytotoxic,hypoglycemic activity and phytochemical analysis of Rubus imperialis (Rosaceae)

Rubus imperialis, Artemia salina, 3-O-methylellagic-4'-O-alpha-rhamnose Acid Screening of different extracts, fractions and compounds from Rubus imperialis Chum. Schl. (Rosaceae) has been conduced using the brine shrimp microwell cytotoxicity assay. Three parts of the plant (methanolic extract from leaves, roots and stems), three fractions from roots (hexane, ethyl acetate and butanol) and three isolated compounds (niga-ichigoside F1, 23-hydroxytormentic acid, ellagic acid derivative) were tested. The most promising material (LC50 <1000 microg/ml) were the methanolic extract and ethyl acetate fraction from roots. However, there was little correlation observed in the degree of toxicities observed between the isolated compounds. On the other hand, the cytotoxicity and in vivo assays confirmed the hypoglycemic activity of methanolic extract and validated the Brazilian popular use of R. imperialis as an antidiabetic agent.     

A demographic study of the apomictic blackberry, Rubus nessensis (Rosaceae)

Ten stands of Rubus nessensis , an apomictic blackberry, were studied. Perennial stools produce biennial shoots that flower in their second year. The stools tend to produce shoots of similar height for several consecutive years. Flowering, but not relative fruit set, is dependent on shoot height. Shoot height and density appear to be positively related, implying that intraspecific competition is of little importance for plant vigour. Depletion time varies greatly between stands (4–29 years), being comparatively longer in stands with short shoots. New establishment is sparse and takes place mostly by root suckering.     

Foliar indumentum in central‐European Rubus species (Rosaceae) and its contribution to the systematics of the group

The foliar indumentum of 94 taxa of Rubus has been surveyed by scanning electron microscopy. The analysed species belonged to five subgenera. Rubus subgen. Rubus with its three sections and 21 series was the most numerously represented. In all studied species, indumentum was present, but the species differed more or less from each other with respect to the density of the indumentum on the abaxial leaf surface. Three main hair types were present: simple eglandular (unbranched) trichomes, branched eglandular trichomes, and very short secretory uni‐seriate trichomes; subtypes were distinguished according to trichome size. Apart from investigating separate traits, we described character patterns for the best represented and homogeneous series: Discolores, Subthyrsoidei, Rhamnifolii and Rubus. Other large groups (Sylvatici, Glandulosi and Micantes) were more diverse.