Unidirectional hybridization at a species' range boundary: implications for habitat tracking

Aim  Introgressive hybridization between a locally rare species and a more abundant congener can drive population extinction via genetic assimilation, or the replacement of the rare species gene pool with that of the common species. To date, however, few studies have assessed the effects of such processes at the limits of species' distribution ranges. In this study, we have examined the potential for hybridization between range-edge populations of the wintergreen Pyrola minor and sympatric populations of Pyrola grandiflora .
Location  Qeqertarsuaq, Greenland and Churchill, Manitoba, Canada.
Methods  Genetic analysis of samples from Greenland and Canada was carried out using a combination of nuclear and chloroplast single nucleotide polymorphisms (SNPs).
Results  Analysis of nuclear SNPs confirmed hybridization in populations of morphologically intermediate individuals, as well as revealing the existence of cryptic hybrids in ostensibly morphologically pure P. minor populations. Analysis of chloroplast SNPs revealed that this hybridization is unidirectional and suggests that hybrids originate via pollen swamping of P. minor by the more common P. grandiflora .
Main conclusions  Extensive unidirectional hybridization may lead to the extinction of peripheral populations of P. minor where the two species grow sympatrically. Extinction could occur as a result of genetic assimilation where F₁s are fertile, or via the removal of unidirectionally pollinated sterile F₁s, or by a combination of these processes. This could compromise the ability of species to respond to climate change via habitat tracking, although the final outcome of these processes may ultimately depend on the rate of global climate change and its effect on the species' distributions.     

A comparative study of the North AmericanPyrola asarifolia and its Asian vicariad,P. incarnata (Ericaceae)

Samples of North AmericanPyrola asarifolia and its Asian vicariad,P. incarnata, were compared in morphology and leaf flavonol constituents. No qualitatively distinct attributes separate the plants from these two regions. In addition, a broad overlap exists in the ranges of the 11 morphological characteristics examined. Both Asian and North American plants exhibit some regional differentiation, but no simple clinal pattern is evident. Sepal width is the only morphological characteristic that exhibits a bimodal tendency in sample means. Asian plants have significantly narrower sepals compared with the North American samples. The chromatographic pattern of leaf flavonols in the Asian plants is distinct from the North American because of the reduced number of compounds present and in having one large, highly concentrated quercetin glycoside as the major constituent. The Asian vicariad is recognized asP. asarifolia Michaux subsp.incarnata (DC.) Haber & Takahashi, comb. nov. It is also considered to have a close affinity with the EurasianP. rotundifolia.     

鹿衔草化学成分的研究：羟基肾叶鹿蹄草甙的结构鉴定

从鹿衔草（Ｐｙｒｏｌａ ｃａｌｌｉａｎｔｈａ Ｈ．Ａｎｄｒｅｓ）分离得到两个化合物。经光谱分析,确定其中１个化合物为新化合物,命名为羟基肾叶鹿蹄草甙（１, ｈｙｄｒｏｘｙｌｒｅｎｉｆｏｌｉｎ）,另一化合物为儿茶素（３）。     

Chemical Constituents of Pyrola calliantha H. Andres: The Structure and Identification of Hydroxylrenifolin

Pyrola calliantha is a traditional Chinese medicinal plant, from which two chemical compounds were isolated. On the basis of spectroscopy (VU, IR, NMR, MS), a new compound, named hydroxylrenifolin was elucidated as 8-β-glucosyloxy-2-hydroxymethyl-7- methyl-1, 4-dihydronapthalene-5-ol (1). And another known compound was identified as catechin (3).     

基于层次-向量法分析的普通鹿蹄草品质与生态因子的相关性

 采用层次-向量法, 从生态因子、有效成分含量、抗氧化活性3个层次, 分析了层次间关系, 研究了生态因子对普通鹿蹄草(Pyrola decorata)品质的影响, 揭示影响其有效成分含量的生态主导因子。结果表明: 不同地区普通鹿蹄草的4种有效成分含量及抗氧化活性差异显著。抗氧化活性(DPPH_IC50值)与单宁、金丝桃苷、槲皮素含量呈负相关关系, 其相关系数分别为: –0.829、–0.378和–0.749, 与总黄酮含量表现为正相关(p = 0.260)。单宁含量和槲皮素含量是影响抗氧化活性的重要指标, 其含量增加时DPPH_IC50值下降, 抗氧化活性增强。年平均气温、一月份平均气温、年积温、年极高气温、无霜期、土壤全氮、速效氮、速效磷和有机质是影响有效成分含量的主要因子, 其中土壤因子对有效成分含量的影响更显著。土壤因子对单宁和槲皮素含量的影响最大, 对金丝桃苷含量影响最小; 气候因子对4种有效成分含量影响较弱且对各成分的影响程度基本相同。研究结果表明, 选择合适的生境, 尤其是土壤因子可有效地提高普通鹿蹄草的品质。     

鹿蹄草植物的研究与应用

对鹿蹄草植物的自然资源分布、化学成分、药理作用、及其应用的相关研究做了综述。该植物在世界各地广泛分布、含有鹿蹄草素等多种化学成分,药理研究证明其具有抗菌、抗病毒、消炎、镇痛作用、对心脑血管系统等作用,主要应用在医药工业、食品工业和园林绿化面。最后对该属植物的研究前景做了展望。     

Studies on the life history of the population of an evergreen herb,Pyrola japonica,on the forest floor in a warm temperate region

Photosynthetic and respiratory activities and gross production in relation to temperature conditions were investigated in the population of an evergreen herb,Pyrola japonica, growing on the floor of a deciduous forest in the warm temperate region of central Japan. Analysis of the temperature-photosynthesis relationship ofP. japonica leaves during the growing season indicated distinct seasonal changes in the temperature optimum for photosynthesis. This population was found to be acclimatable to ambient air temperatures exceeding 15C, but this acclimation became less pronounced under thermal conditions below 15 C. This plant possessed narrow photosynthetic optima in the warm season but wide optima in the cold season. The shape of the temperature-respiration curve did not vary significantly with the months except for April. The Q₁₀ for respiration between 10 C and 20 C was calculated to be 1.93–2.65. Annual dry matter loss associated with respiration was estimated to amount to 159.1 g d.w.m⁻² based on the measurements of the seasonal changes in the respiratory activity of each organ. Gross production of this population was estimated to be 219.3 g d.w.m⁻² year⁻¹ as the sum total of the net production (60.2 g d.w.m⁻²year⁻¹) and the respiration. Monthly gross production was high in the early growing season, and low and stable in winter.     

兴安鹿蹄草传粉昆虫及其访花行为

对兴安鹿蹄草(Pyrola dahurica(H.Andr.)Kom.)访花昆虫种类、访花频率、访花时间、访花行为进行初步研究。结果表明:(1)兴安鹿蹄草的访花昆虫有3目、10科、16种,其中传粉昆虫为5科9种,主要的传粉昆虫为杂棘蝇Phaonia hybridassp.、熊蜂Bombus ignitus、东北驼花天牛Piidonia puziloi(Soisky)及花蚤Mordellidae sp.。(2)各种传粉昆虫访花频率差异较大,杂棘蝇和花蚤日访花有2次高峰,分别在上午9:00~10:00时和下午14:00~15:00时;熊蜂日访花频率较低,在中午11:00~12:00和下午15:00~16:00时较高;东北驼花天牛日访花高峰出现在中午前后。(3)东北驼花天牛访花时间较长,10~15min,主要吃兴安鹿蹄草花粉。杂棘蝇访花时间较短,10~25s,主要舔食柱头分泌物。熊蜂访花时间最短只有5~10s,主要吃兴安鹿蹄草花粉。     

鹿蹄草化学成分研究

从鹿蹄草(Pyrola callianthaH.Andres)中分离得到11个化合物,经光谱分析确定其结构为(4R)-1-四氢萘酮(1),(4S)-1-四氢萘酮(2),夹竹桃麻素(3),没食子酸(4),3,4-二羟基苯甲酸(5),鹿蹄草素(6),5-羟甲基糠醛(7),金丝桃苷(8),2″-O-没食子酰基金丝桃苷(9),鹿蹄草苷B(10),4-羟基-2,7-二甲基萘基-1-O-β-D-吡喃葡萄糖苷(11)。其中化合物1,2,3,5,6,11为首次从该植物中分离得到,化合物7为首次从该属中分离得到。     

兴安鹿蹄草(Pyrola dahurica (H.Andr.) Kom.)雪盖前后丙二醛及渗透调节物质含量的变化

研究了自然生境下生长的兴安鹿蹄草(Pyrola dahurica(H.Andr.)Kom.)根状茎及叶片中渗透调节物质、膜脂过氧化产物在雪盖前后的变化。结果表明,在雪盖前期(10月1日～12月15日)兴安鹿蹄草根状茎及叶片中丙二醛(MDA)含量先增高,尔后下降,翌年春季雪盖后期(3月1日～4月15日)MDA含量明显低于雪盖前期,雪盖前期根状茎的丙二醛(MDA)含量低于叶片,雪盖后期高于叶片。可溶性糖、可溶性蛋白质含量在雪盖前期随着温度的下降而升高,11月中旬达到最大,尔后下降,脯氨酸含量先下降尔后升高。雪盖后期渗透调节物质含量高于雪盖前期,可溶性糖含量随气温的升高而下降,可溶性蛋白质与脯氨酸含量随气温升高而大幅度升高,而且成明显正相关。根状茎的可溶性糖含量在雪盖前期、雪盖后期低于叶片,可溶性蛋白质与脯氨酸含量在雪盖前期、雪盖后期高于叶片。兴安鹿蹄草主要通过渗透调节物质含量的变化来适应雪盖前期及雪盖后期低温环境而安全越冬。     

Studies on the life history of an evergreen herb,Pyrola japonica,population on a forest floor in a warm temperate region

The life history and matter economy were studied on an evergreen herb,Pyrola japonica Klenze, population growing on the floor of a deciduous forest in a warm temperate region, central Japan. Seasonal changes in standing crop, bulk density and reserve substance of each organ and in leaf area were investigated over a year. Monthly and annual net production of the population were estimated based on the growth in dry weight and the seasonal dynamics of reserve substance. Seasonal peak value of the monthly net production was 16.7 g d.w.m⁻² in May. The annual net production was estimated to be 60.2 g d.w.m⁻². Two phases were recognized in the annual pattern of development and matter economy of this plant. Phase I, from April to June, was characterized by the development of aboveground vegetative organs and the consumption of reserve substance rrom old organs. Phase II, from July to March, was characterized by the development of reproductive and underground organs, and the accumulation of reserve substance. Phase II was further divided into two sub-phases according to the behavior of the reserve substance and the rate of net production. The production process of the population was compared with those of other evergreen herbs growing on the forest floor in warm temperate regions.     

普通鹿蹄草品质与根际和非根际土壤的关系

以野外调查和室内分析相结合,采用相关分析、主成分分析、回归分析、通径分析等多种分析方法,对秦岭太白山区不同生境下野生普通鹿蹄草有效成分(总黄酮、单宁、金丝桃苷、槲皮素和抗氧化活性(DPPHIC50)与其根际和非根际土壤性质的关系做了研究。结论如下:(1)根际土壤速效钾、pH和脲酶与单个有效成分含量之间呈现出显著或极显著作用,而非根际土壤速效钾与5种有效成分均达到显著或极显著正相关。(2)根际土壤速效钾、pH、转化酶和脲酶是影响普通鹿蹄草有效成分含量的主导因子,而非根际土壤有效氮、速效钾、pH和转化酶是综合影响其含量的主导因子。(3)根际土壤速效钾是影响普通鹿蹄草有效成分含量的主要决策因素,而pH、转化酶和脲酶是其主要限制因素;非根际土壤有效氮和速效钾是影响普通鹿蹄草有效成分含量的主要决策因素,而pH和转化酶是其主要限制因素。由此得出,普通鹿蹄草有效成分含量受根际和非根际多种土壤因子的综合影响,且土壤速效钾含量、pH、转化酶是影响其含量的共同因子。     

兴安鹿蹄草叶片雪盖初期与雪盖后期保护酶活性的变化规律

研究了自然生境下生长的兴安鹿蹄草(Pyrola dahurica)叶片在雪盖初期、后期的细胞膜相对透性、膜质过氧化产物丙二醛(MDA)含量、超氧化物歧化酶(SOD)及过氧化物酶(POD)活性的变化, 结果表明: 兴安鹿蹄草顺利越冬取决于两个关键时期, 即雪盖初期和雪盖后期, 雪盖初期包括积雪期和盛雪期, 雪盖后期包括融雪初期和融雪后期。积雪期(11月1日~12月1日)兴安鹿蹄草随着温度的降低叶片中的MDA含量逐渐增高, 细胞膜相对透性增大, SOD和POD活性增强; 进入盛雪期(12月1日以后), 雪盖下温度较高而恒定, 兴安鹿蹄草叶片MDA含量减少, 细胞膜相对透性减低, SOD和POD活性减弱。翌年春天融雪初期(3月1日~3月15日), 雪盖下温度降低, 兴安鹿蹄草叶片中的MDA含量增高, 但低于积雪期; 细胞膜相对透性增大, 且高于积雪期; SOD和POD活性增强, 但低于积雪期; 融雪后期(3月中旬以后)兴安鹿蹄草叶片MDA含量减少, 细胞膜相对透性减低, SOD和POD活性减弱。     

兴安鹿蹄草（Pyrola dahurica (H.Andr.) Kom.）雪盖前后丙二醛及渗透调节物质含量的变化

研究了自然生境下生长的兴安鹿蹄草（Pyrola dahurica (H.Andr.) Kom.）根状茎及叶片中渗透调节物质、膜脂过氧化产物在雪盖前后的变化。结果表明,在雪盖前期（10月1日~12月15日）兴安鹿蹄草根状茎及叶片中丙二醛（MDA）含量先增高,尔后下降,翌年春季雪盖后期（3月1日~4月15日）MDA含量明显低于雪盖前期,雪盖前期根状茎的丙二醛（MDA）含量低于叶片,雪盖后期高于叶片。可溶性糖、可溶性蛋白质含量在雪盖前期随着温度的下降而升高,11月中旬达到最大,尔后下降,脯氨酸含量先下降尔后升高。雪盖后期渗透调节物质含量高于雪盖前期,可溶性糖含量随气温的升高而下降,可溶性蛋白质与脯氨酸含量随气温升高而大幅度升高,而且成明显正相关。根状茎的可溶性糖含量在雪盖前期、雪盖后期低于叶片,可溶性蛋白质与脯氨酸含量在雪盖前期、雪盖后期高于叶片。兴安鹿蹄草主要通过渗透调节物质含量的变化来适应雪盖前期及雪盖后期低温环境而安全越冬。     

鹿蹄草中2″-O-没食子酰基金丝桃苷的提取工艺研究

以东北野生鹿蹄草为原料,利用超声辅助提取技术进行提取,在单因素实验的基础上对提取条件进行了考察,根据CCD(Central Composite Design)实验设计原理,采用3因素3水平的响应面分析法,以鹿蹄草中主要黄酮2″-O-没食子酰基金丝桃苷(2″-O-galloylhyperin)为指标,对提取过程进行优化,得到最佳工艺参数为：提取时间45 min,超声功率40 kHz,提取次数3次,提取温度60℃,液固比33∶1,乙醇浓度50%。在最佳提取条件下,2″-O-没食子酰基金丝桃苷的提取率可达5.024 mg·g^-1。     

Light environment and carbon gain of understory herbs associated with sunflecks in a warm temperate deciduous forest in Japan

Seasonal variation in the light environment on the forest floor of a deciduous forest was investigated with special reference to sunflecks. Diurnal variations and seasonal changes in frequency and irradiation period of the sunflecks (sunfleck duration) were measured. The hourly total sunfleck duration varied seasonally; that is, 30–40 min in spring and autumn and about 15–20 min in summer. There was no large variation in the hourly sunfleck duration during daytime hours (from 9.00 to 15.00 h). The emergence frequency of sunflecks was 1.3–4.8 per h with two peaks, one in the morning and one in the afternoon. The mean duration of a sunfleck, however, showed a characteristic daily pattern with a peak around noon. Sunfleck duration was long around noon, ranging from 12 to 18 min, and short around 10.00 and 14.00 h, ranging from 6 to 10 min. Using the light photosynthesis curves ofPyrola japonica andSyneilesis palmata (Koizumi & Oshima 1985), the contribution of sunflecks to the dry matter production of these understory species was evaluated. It was shown that the sunflecks contributed 7–10% of the carbon gain inS. palmata, but only 2–3% of that inP. japonica.     

Wide geographical and ecological distribution of nitrogen and carbon gains from fungi in pyroloids and monotropoids (Ericaceae) and in orchids

* Stable isotope abundance analyses recently revealed that some European green orchids and pyroloids (Ericaceae) are partially myco-heterotrophic, exploiting mycorrhizal fungi for organic carbon and nitrogen. Here we investigate related species to assess their nutritional mode across various forest and climate types in Germany and California. * C- and N-isotope signatures of five green pyroloids, three green orchids and several obligate myco-heterotrophic species (including the putatively fully myco-heterotrophic Pyrola aphylla) were analysed to quantify the green plants' nutrient gain from their fungal partners and to investigate the constancy of enrichment in (13)C and (15)N of fully myco-heterotrophic plants from diverse taxa and locations relative to neighbouring autotrophic plants. * All green pyroloid and one orchid species showed significant (15)N enrichment, confirming incorporation of fungi-derived N compounds while heterotrophic C gain was detected only under low irradiance in Orthilia secunda. Pyrola aphylla had an isotope signature equivalent to those of fully myco-heterotrophic plants. * It is demonstrated that primarily N gain from mycorrhizal fungi occurred in all taxonomic groups investigated across a wide range of geographical and ecological contexts. The (13)C and (15)N enrichment of obligate myco-heterotrophic plants relative to accompanying autotrophic plants turned out as a fairly constant parameter.     

Tetralones and flavonoids from Pyrola calliantha

Two new tetralones, pyrolones A (1) and B (2), and a new flavonol glycoside, 2'-O-(4-hydroxybenzoyl)hyperin (3), were isolated from Pyrola calliantha (whole plant), together with six structurally related compounds, including 2'-O-galloylhyperin (4), hyperin (5), formononetin (6), quercetin 3-O-alpha-L-arabinopyranoside (7), quercetin 3-O-alpha-L-arabinofuranoside (8), and kaempferol 3-O-beta-D-galactopyranoside (9). The structures and absolute configurations of the new compounds were elucidated on the basis of spectroscopic (UV, ORD, CD, NMR) and mass-spectrometric (HR-ESI-MS) analyses.     

Search for the pharmacophore in prazosin for Transport-P

Partial structures of prazosin have been synthesised and tested for inhibition of Transport-P in order to identify the structural features of prazosin, which appear to be involved in binding to the putative transporter. It is shown that the pyrimidinyl 4-amino group is critically important for binding but that the 6,7-dimethoxy and 2-furoyl groups are not essential.