陕西省种子植物新资料

报道了陕西省植物分布新记录2种1亚种。新记录种分别是梨序楼梯草(Elatostema ficoides Wedd.)和粉叶栒子(Cotoneaster glaucophyllus Franch.),新记录亚种是藤山柳原亚种[Clematoclethra scandens(Franch.)Maxim.subsp.scandens]。     

Distribution and Expression of Elicitin Genes in the Interspecific Hybrid Oomycete Phytophthora alni

Phytophthora alni subsp. alni, P. alni subsp. multiformis, and P. alni subsp. uniformis are responsible for alder disease in Europe. Class I and II elicitin gene patterns of P. alni subsp. alni, P. alni subsp. multiformis, P. alni subsp. uniformis, and the phylogenetically close species P. cambivora and P. fragariae were studied through mRNA sequencing and 3′ untranslated region (3′UTR)-specific PCRs and sequencing. The occurrence of multiple 3′UTR sequences in association with identical elicitin-encoding sequences in P. alni subsp. alni indicated duplication/recombination events. The mRNA pattern displayed by P. alni subsp. alni demonstrated that elicitin genes from all the parental genomes are actually expressed in this allopolyploid taxon. The complementary elicitin patterns resolved confirmed the possible involvement of P. alni subsp. multiformis and P. alni subsp. uniformis in the genesis of the hybrid species P. alni subsp. alni. The occurrence of multiple and common elicitin gene sequences throughout P. cambivora, P. fragariae, and P. alni sensu lato, not observed in other Phytophthora species, suggests that duplication of these genes occurred before the radiation of these species.     

Antibacterial Activities of Nisin Z Encapsulated in Liposomes or Produced In Situ by Mixed Culture during Cheddar Cheese Ripening

This study investigated both the activity of nisin Z, either encapsulated in liposomes or produced in situ by a mixed starter, against Listeria innocua, Lactococcus spp., and Lactobacillus casei subsp. casei and the distribution of nisin Z in a Cheddar cheese matrix. Nisin Z molecules were visualized using gold-labeled anti-nisin Z monoclonal antibodies and transmission electron microscopy (immune-TEM). Experimental Cheddar cheeses were made using a nisinogenic mixed starter culture, containing Lactococcus lactis subsp. lactis biovar diacetylactis UL 719 as the nisin producer and two nisin-tolerant lactococcal strains and L. casei subsp. casei as secondary flora, and ripened at 7°C for 6 months. In some trials, L. innocua was added to cheese milk at 10⁵ to 10⁶ CFU/ml. In 6-month-old cheeses, 90% of the initial activity of encapsulated nisin (280 ± 14 IU/g) was recovered, in contrast to only 12% for initial nisin activity produced in situ by the nisinogenic starter (300 ± 15 IU/g). During ripening, immune-TEM observations showed that encapsulated nisin was located mainly at the fat/casein interface and/or embedded in whey pockets while nisin produced by biovar diacetylactis UL 719 was uniformly distributed in the fresh cheese matrix but concentrated in the fat area as the cheeses aged. Cell membrane in lactococci appeared to be the main nisin target, while in L. casei subsp. casei and L. innocua, nisin was more commonly observed in the cytoplasm. Cell wall disruption and digestion and lysis vesicle formation were common observations among strains exposed to nisin. Immune-TEM observations suggest several modes of action for nisin Z, which may be genus and/or species specific and may include intracellular target-specific activity. It was concluded that nisin-containing liposomes can provide a powerful tool to improve nisin stability and availability in the cheese matrix.     

香槐属分类学研究随记

基于对标本和文献的比较研究,确认豆科香槐属(Cladrastis Raf.)中小叶香槐(C.parvifolia C.Y.Ma)、藤香槐(C.scandens C.Y.Ma)、秦氏香槐(C.chingii DuleyVincent)与本属分布最广的翅荚香槐[C.platycarpa(Maxim.)Makino]为同种植物。其中,小叶香槐被处理为翅荚香槐的一变种,即C.platycarpa var.parvifolia(C.Y.Ma)Z.Q.Song,D.X.XuS.J.Li,藤香槐与秦氏香槐被处理为翅荚香槐原变种的两个新异名。同时讨论了翅荚香槐的分类地位及其散布。     

Genetic relationships between wild progenitor pear (Pyrus L.) species and local cultivars native to Georgia,South Caucasus

The genetic diversity of 108 individuals of wild pear species (Pyrus communis subsp. caucasica, P. balansae, P. salicifolia, P. syriaca, P. demetrii, P. bulgarica, P. ketzkhovelii, P. sachokiana) and 35 samples of local and introduced cultivated pears from the country of Georgia were compared to 73 individuals of wild P. communis subsp. caucasica and P. communis subsp. pyraster in the collection of USDA-ARS National Plant Germplasm System (NPGS). Pyrus communis subsp. caucasica from both Georgia and the NPGS, P. communis subsp. pyraster from the NPGS, and P. salicifolia from Georgia were differentiated, based on analysis of eleven microsatellite markers. In addition, accessions of P. communis subsp. caucasica from Georgia were genetically distinct from accessions of the same subspecies in the NPGS collection that originated from other European and Middle Eastern Asian countries. Local pear cultivars in Georgia were genetically similar to P. communis subsp. caucasica and P. balansae growing wild in Georgia suggesting that they may have originated from native pear trees that could serve as unique genetic resources for pear breeding programmes.     

Genetic relationships among Pistacia species using AFLP markers

This study addresses the phylogenetic relationship between Pistacia species by amplified fragment length polymorphism (AFLP). The plant materials of this study consisted of a total of 44 accessions belonging to P. vera, P. eurycarpa, P. khinjuk, all subspecies of P. atlantica (atlantica, mutica, kurdica and cabulica), three unknown genotypes and three accessions, proposed to be hybrid from P. eurycarpa × P. atlantica. The accessions were from Iran, Turkey, USA and Syria. Six AFLP primer combinations produced a total of 475 fragments, with average of 79.16 fragments per primer pair, of which, 336 bands were polymorphic. Unweighted pair group method based on arithmetic average (UPGMA) analysis was performed on jaccard’s similarity coefficient matrix and also average similarity of each species. According to the results, two main clusters were developed and P. vera, P. eurycarpa, P. atlantica (subsp. atlantica, kurdica, mutica, cabulica) and the hybrid genotypes located in the first main cluster. P. khinjuk accessions from Iran and USA localized in second main cluster. The hybrid accessions located between eurycarpa and atlantica species and their hybrid nature between these two species were confirmed. One of the unknown accessions clustered with the hybrid ones and the two other were grouped closely with P. Khinjuk. According to this study, the closest species to P. vera was Eurycarpa group, followed by P. atlantica. UPGMA analysis separated P. atlantica subsp. mutica and cabulica from P. atlantica and P. eurycarpa. Subspecies mutica and cabulica were two closest genotypes; hence, P. atlantica subsp. mutica could be classified as a distinct species as P. mutica and the cabulica as a subspecies of P. mutica. This study revealed that P. eurycarpa is synonym for P. atlantica subsp. kurdica and should be considered distinct from P. atlantica; however, P. atlantica showed a closer genetic similarity to P. eurycarpa than the other species.     

Number of source populations as a potential driver of pine invasions in Brazil

To understand current patterns of Pinus invasion in an Araucaria forest in southern Brazil, we quantified invasion at the local scale and compared it with habitat characteristics, propagule size, and number of source populations, using generalized linear models. We also compared observed and expected invasive species status based on a previously developed model (Z scores) using Chi square and correlation tests to evaluate the predictability of species status based on their traits. Of the 16 Pinus species currently present in the site, three are invasive (P. elliottii, P. glabra, and P. taeda), three are naturalized (P. clausa, P. oocarpa, and P. pseudostrobus), and ten are present only as the originally planted individuals. While P. taeda spread the farthest, P. glabra had greater overall density, but none of the invasive species has spread more than 250 m in 45 years. Invasive Pinus plants were found where forest tree density was below 805 trees ha^?1, and invasive Pinus density decreased log-linearly with an increase in native tree density. Number of individuals introduced and number of source populations were strong predictors of naturalization, thus both propagule size and propagule diversity can potentially be driving invasion success. Z scores based on species traits did not predict which species would invade in Rio Negro. Our findings suggest that Araucaria forests might not resist invasion by Pinus as recently suggested and support the hypothesis that propagule pressure is a fundamental driver of invasions with propagule diversity being a possible component of this mechanism.     

A new species and a new subspecies of the planthopper of the family Issidae (Hemiptera, Fulgoroidea) from Greece

Tshurtshurnella konstanto sp. n. and Zopherisca tendinosa skaloula subsp. n. are described from Greece. T. konstanto differs from the all congeners in the male anal tube with the pointed and turned-up apex. Z. tendinosa skaloula subsp. n. differs from Z. tendinosa tendinosa in the presence of a transverse row of teeth on the dorsolateral phallobase lobes. Z. tendinosa tendinosa is distributed in Croatia, southern Bulgaria, and northwestern Greece, whereas Z. tendinosa skaloula subsp. n. occurs in southeastern Greece including the Peloponnesus.     

Two tirucallane derivatives from Paramignya scandens and their cytotoxic activity

Various chromatographic separations of the methanolic extract of Paramignya scandens stem and leaves resulted in the isolation of two new tirucallane derivatives, paramignyols A and B (1 and 2). Their structures were established by HR-ESI-MS, 1D and 2D NMR experiments, as well as, comparison with literature data. Compounds 1 and 2 showed significant cytotoxic activity (IC₅₀s ∼ 3.55–10.50 μM) on four tested human cancer cell lines: KB (epidermoid carcinoma), SK-Mel-2 (melanoma), LU-1 (lung adenocarcinoma), and MCF7 (breast cancer). This is the first report on chemical constituents and biological activities of P. scandens.     

Differentiation of Paenibacillus larvae subsp. larvae, the Cause of American Foulbrood of Honeybees, by Using PCR and Restriction Fragment Analysis of Genes Encoding 16S rRNA

A rapid procedure for the identification of Paenibacillus larvae subsp. larvae, the causal agent of American foulbrood (AFB) disease of honeybees (Apis mellifera L.), based on PCR and restriction fragment analysis of the 16S rRNA genes (rDNA) is described. Eighty-six bacterial strains belonging to 39 species of the genera Paenibacillus, Bacillus, Brevibacillus, and Virgibacillus were characterized. Amplified rDNA was digested with seven restriction endonucleases. The combined data from restriction analysis enabled us to distinguish 35 profiles. Cluster analysis revealed that P. larvae subsp. larvae and Paenibacillus larvae subsp. pulvifaciens formed a group with about 90% similarity; however, the P. larvae subsp. larvae restriction fragment length polymorphism pattern produced by endonuclease HaeIII was found to be unique and distinguishable among other closely related bacteria. This pattern was associated with DNA extracted directly from honeybee brood samples showing positive AFB clinical signs that yielded the restriction profile characteristic of P. larvae subsp. larvae, while no amplification product was obtained from healthy larvae. The method described here is particularly useful because of the short time required to carry it out and because it allows the differentiation of P. larvae subsp. larvae-infected larvae from all other species found in apiarian sources.     

Genetic relationships among Pistacia species studied by SAMPL markers

Pistachio is economically important in Iran. Selection of suitable rootstocks, resistant to unfavorable and soil conditions and diseases, is important for increasing yield and the acreage of this crop. It is essential to identify the genetic relationships among Pistacia species for the breeding of pistachio rootstocks. The goal of this study was to determine the genetic relationship among Pistacia species (P. vera L., P. khinjuk Stocks., P. eurycarpa Yalt., P. atlantica subsp. atlantica Zoh., P. atlantica subsp. mutica Fish et C.A. Mey and P. atlantica subsp. cabulica Stocks.) with potential in the breeding of rootstocks using the selective amplification of microsatellite polymorphic loci (SAMPL) technique. Six primer combinations produced a total of 182 bands, with an average of 30.33 bands per primer pair, of which 128 were polymorphic. Three branches were obtained, the first containing P. vera, and the second containing P. khinjuk, P. eurycarpa, P. atlantica and subspecies mutica and cabulica, with numerous leaflets clustered in the third branch. UPGMA analysis separated P. atlantica subspecies from P. eurycarpa.     

Intracellular localization of certain photosynthetic enzymes in bundle sheath cells of plants possessing the C4 pathway of photosynthesis.

Bundle sheath cells were enzymatically isolated from representatives of three groups of C₄ plants: Zea mays (NADP malic enzyme type), Panicum miliaceum (NAD malic enzyme type), and Panicum maximum (phosphoenolpyruvate (PEP) carboxykinase type). Cellular organelles from bundle sheath homogenates were partially resolved by differential centrifugation and on isopycnic sucrose density gradients in order to study compartmentation of photosynthetic enzymes. A 48-h-dark pretreatment of the leaves allowed the isolation of relatively intact chloroplasts. Enzymes that decarboxylate C₄ acids and furnish CO₂ to the Calvin cycle are localized as follows: NADP malic enzyme, chloroplastic in Z. mays; NAD malic enzyme, mitochondrial in all three species; PEP carboxykinase, chloroplastic in P. maximum. The activity of NAD malic enzyme in the three species was in the order of P. miliaceum > P. maximum > Z. mays. There were high levels of aspartate and alanine aminotransferases in bundle sheath extracts of P. miliaceum and P. maximum and substantial activity in Z. mays. In all three species, aspartate aminotransferase was mitochondrial whereas alanine aminotransferase was cytoplasmic. Based on the activity and localization of certain enzymes, the concept for aspartate and malate as transport metabolites from mesophyll to bundle sheath cells in C₄ species of the three C₄ groups is discussed.     

Variation in leaf nitrogen and phosphorus stoichiometry in the nitrogen-fixing Chinese sea-buckthorn (Hippophae rhamnoides L. subsp. sinensis Rousi) across northern China

Nitrogen (N) and phosphorus (P) concentrations and N:P ratios in terrestrial plants and their patterns of change along environmental gradients are important traits for plant adaptation to changes. We determined the leaf N and P concentrations of Chinese sea-buckthorn (Hippophae rhamnoides L. subsp. sinensis Rousi), a non-legume species with symbiotic N fixation (SNF), at 37 sites across northern China and explored their geographical patterns in relation to climate and soil factors. (1) The mean leaf N, P, and N:P ratio were 36.5, 2.1 mg g^?1, and 17.6, respectively, higher than the mean values of most shrub species in the region. (2) Leaf N was correlated with soil mineral N in cool areas (mean annual temperature MAT <3 °C) but with temperature in warm areas (MAT >3 °C). The high leaf N and divergent leaf N–soil N relationship suggested the importance of SNF in plant N uptake; SNF increases with temperature and is probably the major N source in warm areas. (3) Leaf P was positively related to mean annual precipitation. Leaf N:P ratio was primarily driven by changes in leaf P. The high leaf P reflected the greater requirements of the N-fixing species for P. Our results represent a major advance in understanding the elemental stoichiometry of non-legume N-fixing plants, indicating high P and N requirements and a shift in N source from SNF to soil as temperature declines. This knowledge will help in assessing the habitat suitability for the species and predicting the species dynamics under environmental changes.     

A PCR-based analysis of plant DNA reveals the feeding preferences of <Emphasis Type="Italic">Apolygus lucorum</Emphasis> (Heteroptera: Miridae)

The mirid bug Apolygus lucorum (Meyer-Dür) (Heteroptera: Miridae) is a severe pest of cotton and other crops in China. The feeding preferences of this pest are unclear due to its frequent movement among different host plants and the inconspicuous signs of its feeding. Here, we present results of a field trial that used direct observation of bug densities and a PCR-based molecular detection assay to detect plant DNA in bugs to explore relationships between A. lucorum population abundance and its feeding preference between two host plants, Humulus scandens (Loureiro) Merrill and Medicago sativa L. The field-plot samples showed that A. lucorum adults generally prefer flowering host plants. Its density was significantly higher on flowering H. scandens than on seedlings of M. sativa, and a similarly higher bug density was observed on flowering M. sativa than on seedlings of H. scandens. In the laboratory, we designed two pairs of species-specific primers targeting the trnL-F region for H. scandens and M. sativa, respectively. The detectability of plant DNA generally decreased with time post-feeding, and the half-life of plant DNA detection (DS₅₀) in the gut was estimated as 6.26 h for H. scandens and 3.79 h for M. sativa with significant differences between each other. In mirid bugs exposed to seedlings of H. scandens and flowering M. sativa, the detection rate of M. sativa DNA was significantly higher than that of H. scandens. Meanwhile, in mirid bugs exposed to seedlings of M. sativa and flowering H. scandens, a significantly higher detection rate of H. scandens DNA was found. We developed a useful tool to detect the remaining plant food species specifically from the gut of A. lucorum in the current study. We provided direct evidence of its feeding preference between H. scandens and M. sativa at different growth stages, which strongly supported a positive correlation between population abundance and feeding preference of A. lucorum on different plants under field conditions. The findings provide new insights into the understanding of A. lucorum’s feeding preference, and are helpful for developing the strategies to control this pest.     

Morphogenetic and diurnal variation of hypericin in some Hypericum species from Turkey during the course of ontogenesis

The genus Hypericum has received considerable interest from scientists, as it is a source of a variety of biologically active compounds including the hypericins. The present study was conducted to determine ontogenetic, morphogenetic and diurnal variation of the total hypericins content in some species of Hypericum growing in Turkey namely, Hypericum aviculariifolium subsp. depilatum var. depilatum (endemic), Hypericum perforatum and Hypericum pruinatum. The Hypericum plants were harvested from wild populations at vegetative, floral budding, full flowering, fresh fruiting and mature fruiting stages four times a day. Plants were dissected into stem, leaf and reproductive tissues, which were dried separately, and subsequently assayed for total hypericin content. The density of dark glands on leaves at full flowering plants was determined for each species. Floral parts had the highest hypericin content in all species tested. But diurnal fluctuation in the hypericin content of whole plant during the course of ontogenesis varied among the species. It reached the highest level at floral budding and tended to increase at night in H. aviculariifolium subsp. depilatum var. depilatum and H. pruinatum, whereas in H. perforatum hypericin content was the highest at full flowering and no diurnal fluctuation was observed. In general, hypericin content of leaves and whole plant was higher in H. aviculariifolium subsp. depilatum var. depilatum whose leaves had more numerous dark glands than those of the two other species.     

Growth of Stigeoclonium and Oedogonium species in artificial ammonium-N and phosphate-P gradients

Four benthic filamentous Chlorophycean species (three Stigeoclonium species and one Oedogonium species) were obtained from two ditches, influenced, respectively, by the point discharges of pig farm and sewage treatment plant effluents. The ditches showed a gradual change in water chemistry, particularly with regard to ammonium-N and phosphate-P. The growth of the algae was studied in artificial ammonium-N (concentration range of 1–100 mg l^?1) and phosphate-P gradients (concentration range of 0.1–15 mg l^?1), which were based on concentrations of these nutrients in the ditches. Maximum growth in ammonium-N was attained for S. aestivale Hazen Z1 and S helveticum Vischer P4 at 50 mg l^?1, for S. aestivale Z4 and Oedogonium sp. Z4 at 10 mg l^?1, and for S. amoenum Kützing P2 at 5 mg l^?1. Maximum growth in phosphate-P was attained for S. helveticum P4 at 15 mg l^?1, for S. aestivale Z1 and S. amoenum P2 at 1.5 mg l^?1, and for S. aestivale Z4 and Oedogonium sp. Z4 at 1 mg l^?1.It is concluded that the ammonium-N and phosphate-P levels of ditches determined the distribution of the algae along the ditches, and therefore influenced the species composition of the periphyton communities.The study revealed a population differentiation with regard to ammonium-N in two closely adjacent populations of S. aestivale.     

Biochemical evidence bearing on the domestication of<Emphasis Type="Italic">Phaseolus</Emphasis> (Fabaceae) beans

The genusPhaseolus (Fabaceae) consists of some 50 species, all of which are distributed in the Americas. Four of these contain cultigens.P. vulgaris (common bean),P. lunatus (lima bean),P. acutifolius (tepary bean),P. coccineus subsp.coccineus (runner bean); andP. coccineus subsp.polyanthus (no English vernacular name). Biochemical markers—phaseolin seed storage protein and isozymes—have provided new evidence on the organization of the first three species. Domestication has possibly caused a strong reduction in genetic diversity inP. vulgaris andP. acutifolius. BothP. vulgaris andP. lunatus cultivars result from at least two independent domestications, in Mesoamerica and in the Andes. These two species consist of two gene pools, each of which includes wild ancestors and their respective cultivated descendants. Our findings suggest the need for additional emphasis on genetic conservation of wild ancestors and their use in breeding programs and for a comparison of inter-gene pool vs. intra-gene pool crosses in breeding programs.     

中国特有属藤山柳属(猕猴桃科)植物的叶表皮形态及其分类学意义

由于形态特征变异和地理分布区域存在重叠,中国特有属藤山柳属(猕猴桃科)的物种划分问题长期以来存在争议,曾被分为20种或修订为含1种4个亚种的单型属。该研究选取了在形态和地理分布上有代表性的29个居群的184份标本,利用光学显微镜和扫描电镜观察了叶表皮形态和微形态特征,以探讨它们的分类学意义。结果表明:(1)藤山柳属植物叶表皮毛被的形态和微形态特征有3类,即光滑-短柱状毛、刚毛-长柱状毛/长刺毛、绒毛-单列多细胞毛,且这些特征在居群间差异明显,并各具明显的地理分布格局,支持把藤山柳属分为3类,即光滑类、刚毛类和绒毛类。(2)3类藤山柳植物在个别居群表现出部分同域分布现象,在峨眉山不同海拔高度的3个居群存在垂直地带性分布特点。(3)藤山柳属植物叶表皮的其他形态特征,如不规则型表皮细胞、6类气孔器、叶表皮初级蜡质纹饰以网状隆起为主,伴随着2～4类次级纹饰,在居群间变化多样等均没有明显的分类学意义。(4)由于具有相同的叶表皮形态特征和地理分布,建议把繁花藤山柳合并到绒毛藤山柳,故支持藤山柳属是1个正处于分化进程中的单型属,包括1个种3个亚种。     

Novitates florae cubanae

The author describes 5 new species (Brunfelsia Acunae, Cocclcypselum glaberimum, Dioscorea montecristina, Ipomoea montecristina andPavonia lagunarum), 1 subspecies (Fleuria cuneata subsp,horrida), 4 varieties and 2 forms from Cuba, publishes some new combinations and refers on 6 species new for Cuba.     

Genome size variation and species relationships in the genus Hydrangea

Genome size and base composition in 16 species and subspecies of the Hydrangea, a woody ornamental genus of Hydrangeaceae, were evaluated by flow cytometry in relation to their chromosome number. This is the first such study concerning the genome size of these species together with a karyotype study of the most important species, Hydrangea macrophylla subsp. macrophylla (Hortensia), from an economical point of view. The 2C DNA content ranged from 1.95 pg in Hydrangea quercifolia to 5.00 pg in Hydrangea involucrata. The base composition ranged from 39.9% GC in Hydrangea aspera subsp. sargentiana to 41.1% in Hydrangea scandens subsp. scandens (significant difference at p < 0.05). The smallest genome sizes were those of the three species originating from North or South America. Most of the species studied presented a chromosome number of 2n = 2x = 36, except for those of the section Aspereae which showed 2n = 30, 34 and 36. A primary karyotype has been made for the first time for H. macrophylla subsp. macrophylla. Phylogenetic relationships between species, the origin of chromosome number and an exploration of the genetic diversity within the genus are discussed. Received: 24 July 2000 / Accepted: 31 October 2000