A New Iridoid Glycoside and a New Iridoid from Pedicularis kansuensis f. albiflora

A new iridoid glycoside 1 and a new iridoid 2 were isolated from the whole plant of Pedicularis kansuensis f. albiflora. Their structures were elucidated by spectroscopie methods.

Two New Neolignan Glucosides from Pedicularis Verticillata

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Fast and abundant in vitro spontaneous haustorium formation in root hemiparasitic plant Pedicularis kansuensis Maxim. (Orobanchaceae)

Haustorium formation is the characteristic feature of all parasitic plants and a vital process for successful parasitism.Previous investigations on haustorium initiation and development are constricted to induced processes by host-derived signals or synthetic analogs.Spontaneous haustorium formation in the absence of host signals,a process representing an early stage in the evolution of parasitic plants,remains largely unexplored.Lack of fast and frequent formation of spontaneous haustoria greatly hinders full understanding of haustorium formation in root hemiparasites.In this study,seedlings of Pedicularis kansuensis Maxim.,a facultative root hemiparasitic species in Orobanchaceae observed to produce many spontaneous haustoria,were grown in autoclaved water agar in the absence of any known haustoriuminducing stimulants.We aimed to test the temporal and developmental pattern of spontaneous haustorium formation.Also,effects of sucrose supply and root contact on spontaneous haustorium formation were tested.Spontaneous haustoria were observed starting from six days after germination,much earlier than previously reported root hemiparasites.A majority of the spontaneous haustoria formed on lateral roots.Percentage of seedlings with spontaneous haustoria was 28.8% when grown on water agar plates,with a mean of four haustoria per seedling two weeks after germination.Haustorium formation by seedlings grown in water agar amended with 2% sucrose was more than twice of those without sucrose amendment.Singly grown seedlings were able to develop spontaneous haustoria at similar levels as those grown with another conspecific seedling.In view of the fast and abundant formation of spontaneous haustoria,P.kansuensis may be developed as an excellent experimental system in future investigations for unraveling endogenous regulation of haustorium initiation and development in root hemiparasitic plants.

A New Neolignan Glycoside from Pedicularis armata

A new neolignan glycoside named armaoside (1) was isolated from the whole plant of Pedicularis armata Maxim. Its structure was elucidated by spectroscopic and chemical methods. Antibacterial assay showed that it has moderately antibacterial activities against Eschecichia coli, Bacillus subtilis and Staphylococcus aureus.

Phenotypic plasticity of floral traits and pollination adaption in an alpine plant Pedicularis siphonantha D. Don when transplanted from higher to lower elevation in Eastern Himalaya

Phenotypic plasticity and/or pollinatormediated selection may be responsible for the changes in floral traits of plants when they are forced to live in new conditions. Although the two events could be independent, we hypothesized that phenotypic plasticity in floral traits might help to coordinate plant-pollinator interactions and enhance plant reproductive success in changing habitats. To test this hypothesis, we investigated floral traits and pollination on three natural populations of a lousewort(Pedicularis siphonantha) ranging at different elevations, as well as two downward transplanted populations in Shangeri-La County and Deqin County, northwest Yunnan, China. The results indicated that floral traits, i.e. phenology, longevity,display size, corolla tube length and pollen production differed significantly among populations. Moreover,or the two transplanted populations, floral traits diverged from their original populations, but converged to their host populations. Although the phenotypic plasticity in floral traits might be a rapid response to abiotic factor such as warmer environment, the changes in floral traits were found to be well adapted to pollination environment of the host population. Compared with plants of their original habitats in higher elevation, the transplanted individuals advanced flowering time, shortened flower longevity, reduced floral display size and pollen production, received higher visiting frequency and yielded more seeds. These findings suggested that phenotypic plasticity of floral traits might help plants adjust their resource allocation strategy between preand post-pollination stages in response to harsh or temperate conditions, which might correspondingly meet a pollinator-poor or hyphen rich environment.This would be beneficial for the widely-distributed species to adapt to various environmental changes.

TWO NEW IRIDOID GLYCOSIDES FROM PEDICULARIS PLICATA

Two new iridoid glycosides,plicatoside A and plicatoside B,were isolated from whole plants of Pedicularis plicata.Their structures were identified as 2'-O-β-D-glucosyl ixoroside and 4'-O-β-D-xylosyl mussaenoside by means of chemical evidence and spectral data.

Iridoid Glycosides from Pedicularis dolichocymba Hand.-Mazz.

During investigation of the chemical constituents of the whole plant ethanol extract of Pedlcularis dollchocymba Hand.-Mazz. （Scrophularlaceae）, four new irldold glycosides, dolichocymbosides A （compound 1）, B （compound 2）, C （compound 3） and D （compound 4）, were Isolated. Their structures were determined based on spectral data Including 1D and 2D-nuclear magnetic resonance spectroscopy （^1H-^1H COSY, HSQC, HMBC, ROESY） and FAB-MS.

Reaction of hydroxyl radical with phenylpropanoid glycosides from Pedicularis species: a pulse radiolysis study

Using pulse radiolysis technique, the reaction between hydroxyl radical and 7 phenylpropanoidglycosides: echinacoside, verbascoside, leucosceptoside A, martynoside, pediculariosides A, M and N which were isolated from Pedicularis were examined. The rate constants of these reactions were determined by transient absorption spectra. All 7 phenylpropanoid glycosides react with hydroxyl radical at high rate constants within (0.97-1.91)×1010L · mol-1 · s-1. suggesting that they are effective hydroxyl radical scavengers. The results demonstrate that the numbers of phenolic hydroxyl groups of phenylpropanoid glycosides are directly related to their scavenging activities. The scavenging activities are likely related to o-dihydroxy group of phenylpropanoid glycosides as well.

Pollen size strongly correlates with stigma depth among Pedicularis species

Summary Darwin proposed that pollen size should be positively correlated with stigma depth rather than style length among species given that pollen tubes first enter the stigma autotrophically, then grow through the style heterotrophically. However, studies often show a posi-tive relationship between pollen size and style length. Five floral traits were observed to be correlated among 42 bumblebee-pollinated Pedicularis species （Orobancha- ceae） in which stigmas are distinct from styles. The phylogenetic independent contrast analysis revealed that pollen grain volume was more strongly correlated with stigma depth than with style length, consistent with Darwin＇s functional hypothesis between pollen size and stigma depth.

Antioxidant activity and potential ameliorating effective ingredients for high altitude-induced fatigue from Gansu Maxianhao(Pedicularis Kansuensis Maxim.)

OBJECTIVE:To investigate the antioxidant property and potential ameliorating effective ingredients for high altitude-induced fatigue from Gansu Maxianhao(Pedicularis Kansuensis Maxim.).METHODS:Macroporous adsorptive resin combined with polyamide chromatographic column was used to obtain water extract(P1),high polar part(P2),iridoid glycosides part(P3)and phenylethanoid glycosides part(P4)of Gansu Maxianhao(Pedicularis Kansuensis Maxim.).Antioxidant activity of each part was investigated employing a series of in vitro models.Hematoxylin-eosin staining,analysis of blood biochemical parameters,along with molecular analyses examining oxidative stress makers,metabolite,metabolic enzyme and energy substance in liver,skeletal muscle and/or serum were further measured.RESULTS:The results showed phenylethanoid glycosides(Ph Gs)exhibited more effective with 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability,2-2-Azinbis(3-ehtylbenzothiazolin-6-sulfnic Acid)Diammonium Salt+scavenging activity,hydroxyl radical scavenging activity,reducing ability and antioxidant activity to varying extents.Under a hypobaric hypoxia attack in a hypobaric chamber(8000 m,7 consecutive days),Ph Gs was administered to BALB/C mice at doses of 50,200,400 mg/kg and antifatigue property was evaluated using a swimming test at an altitude of 4000 m.The results showed that Ph Gs of Gansu Maxianhao(Pedicularis Kansuensis Maxim.)could significantly prolong the burden swimming time of mice,reduce the hypoxia-induced oxidative stress,remove the accumulated products of metabolism,improve the energy metabolism as well as improve preservation of endogenous glycogen stores.CONCLUSION:The ameliorating effect against altitude-induced fatigue of Ph Gs from Gansu Maxianhao(Pedicularis Kansuensis Maxim.)might come from the alleviation of oxidative stress,reduction of the adverse metabolic products,normalizing energy metabolism and increasing energy substances reserves.Ph Gs is a potential antioxidant and novel remedy for fatigue due to high-altitude hypoxia.

Floral nectary, nectar production dynamics, and floral reproductive isolation among closely related species of Pedicularis

Floral nectar is thought to be one of the most important rewards that attract pollinators in Pedicularis; however, few studies have examined variation of nectary structure and/or nectar secretion in the genus, particularly among closely related species. Here we investigated nectary morphology, nectar quality, and nectar production dynamics in flowers of Pedicularis section Cyathophora. We found a conical floral nectary at the base of the ovary in species of the rex-thamnophila clade. Stomata were found on the sudace of the nectary, and copious starch grains were detected in the nectary tissues. In contrast, a semi-annular nectary was found in flowers of the species of the superba clade. Only a few starch grains were observed in tissues of the semi-annular nectary, and the nectar sugar concentration in these flowers was much lower than that in the flowers of the rexthamnophila clade. Our results indicate that the floral nectary has experienced considerable morphological, structural, and functional differentiation among closely related species of Pedicularis. This could have affected nectar production, leading to a shift of the pollination mode. Our results also imply that variation of the nectary morphology and nectar production may have played an important role in the speciation of sect. Cyathophora.

Pollen-Ovule Ratio and Gamete Investment in Pedicularis （Orobanchaceae）

The Pedicularis species provides ideal materials to study floral evolution because of their substantial flower variation based on a narrow genetic basis, even though they are almost exclusively pollinated by bumblebee. These traits allow us to detect the evolutionary trends of floral parameters without considering genetic background and the difference of pollination vectors. The pollen-ovule ratio is widely used to estimate the pattern of resource investment in two sexual functions in flowering plants. Forty species representing all of the corolla types in Pedicularls were used to study pollen-ovule ratio, gamete investment, and their correlations. Results show that pollen-ovule ratio does not differ among both different corolla types and taxonomic groups. It is therefore suggested that pollen-ovule ratio should be a parallel evolution. The correlations between pollen-ovule ratio and pollen size （-）, and ovule size （＋） can be successfully explained in terms of sex allocation theory. The biological significance of such relationships was also discussed. Additionally, we analyzed the pattern of resource investment into female gamete, which has been somewhat neglected, and found that plants have different patterns of gamete investment between the two sexual functions.

Are long corolla tubes in Pedicularis driven by pollinator selection?

The evolution of long corolla tubes has been hypothesized to be driven by long-tongued pollinators.Corolla tubes in Pedicularis species can be longer than 10 cm which may function as flower stalks to increase visual attractiveness to pollinators because these species provide no nectar and are pollinated by bumblebees. The corolla tube length was manipulated（shorter or longer） in two Pedicularis species in field to examine whether longer tubes are more attractive to pollinators and produce more seeds than short tubes. Our results did not support the pollinator attraction hypothesis, leaving the evolution of long tubes in Pedicularis remains mysterious.

两种同域分布马先蒿植物花特征的表型选择研究

马先蒿属植物花形态的多样化与传粉者的选择密切相关,而同域分布、花期重叠且共享传粉者的亲缘种是如何维持种间差异的,目前还不清楚。研究以青藏高原东缘高寒草地的甘肃马先蒿和半扭卷马先蒿为试验材料,连续两年测定与传粉相关的花特征,通过雌性适合度(种子产量)估计两种马先蒿不同花特征所受的表型选择大小及差异。结果发现:1)两种马先蒿各自的花特征之间均表现出极显著的相关性。甘肃马先蒿的蜜腺深度、花大小及花柱长度之间是显著的正相关,年际间保持一致,而这些花特征与花序数及株高的相关性较低,尤其蜜腺深度与花序数和株高均没有表现出显著的相关性。半扭卷马先蒿的喙长、花柱长度、花大小表现出显著的正相关,但是喙长与其他花特征的相关性在年际间有显著变化。2)两种马先蒿的花序数和株高受到显著的表型选择。除以上特征外,甘肃马先蒿的花大小、花柱长度及蜜腺深度受到显著选择,而半扭卷马先蒿中较少发现对花大小及花柱长度的选择作用,尤其花冠喙长没有受到选择作用。以上结果表明,甘肃马先蒿的蜜腺深度、花大小及花柱长度的发育及功能可能是高度整合的。半扭卷马先蒿中,花柱长度与花大小同样也可能在发育及功能上具有高度整合特性。增加开花数目、延长花期以及增加植株高度,是马先蒿属植物提高雌性适合度(种子产量)的主要手段。甘肃马先蒿种群中,花冠较大、花柱更长、蜜腺更深的个体有更高的雌性适合度,即能够生产更多的种子。半扭卷马先蒿喙长的变化不影响雌性适合度(种子产量),可能与传粉者介导的花粉扩散,即雄性适合度有关。

邓氏马先蒿遗传多样性的ISSR分析

运用ISSR-PCR分子标记技术对邓氏马先蒿(Pedicularis dunniana)云南中甸以及四川木格措两个自然居群的遗传分化以及遗传多样性进行研究。结果表明:物种水平上邓氏马先蒿遗传多样性水平较高(PPB=62%),但居群平均水平很低,云南中甸居群多态性位点百分率只有23%。四川居群也仅仅是27%,AMOVA分析结果表明,居群间基因分化系数Fst=0.7462,即遗传变异绝大部分来源于两居群间,居群间表现出强烈的遗传分化。自交的交配方式以及小居群产生的遗传漂变效可能是造成邓氏马先蒿目前遗传结构的主要原因。

N-P fertilization did not reduce AMF abundance or diversity but alter AMF composition in an alpine grassland infested by a root hemiparasitic plant

Fertilization has been shown to have suppressive effects on arbuscular mycorrhizal fungi(AMF) and root hemiparasites separately in numerous investigations, but its effects on AMF in the presence of root hemiparasites remain untested. In view of the contrasting nutritional effects of AMF and root hemiparasites on host plants, we tested the hypothesis that fertilization may not show strong suppressive effects on AMF when a plant community was infested by abundant hemiparasitic plants. Plants and soil samples were collected from experimental field plots in Bayanbulak Grassland, where N and P fertilizers had been applied for three continuous years for control against a spreading root hemiparasite, Pedicularis kansuensis. Shoot and root biomass of each plant functional group were determined. Root AMF colonization levels, soil spore abundance, and extraradical hyphae length density were measured for three soil depths(0 e10 cm, 10 e20 cm, 20 e30 cm). Partial 18 S r RNA gene sequencing was used to detect AMF diversity and community composition. In addition, we analyzed the relationship between relative abundance of different AMF genera and environmental factors using Spearman's correlation method. In contrast to suppressive effects reported by many previous studies, fertilization showed no significant effects on AMF root colonization or AMF species diversity in the soil. Instead, a marked increase in soil spore abundance and extraradical hyphae length density were observed. However, fertilization altered relative abundance and AMF composition in the soil. Our results support the hypothesis that fertilization does not significantly influence the abundance and diversity of AMF in a plant community infested by P. kansuensis.

轮叶马先蒿危害现状及防除对策

轮叶马先蒿(Pedicularis myriophylla)在新疆巴音布鲁克高寒草地大面积发生,于2004-2005年5月初对其生物学特性、传播方式、分布面积、群落数量特征等进行了观测和调查,并对其进行分析,以了解害草轮叶马先蒿在巴音布鲁克高寒草地的分布情况及其对畜牧业的危害现状。结果表明:轮叶马先蒿的危害面积已高达4.11×104hm2,5月下旬是其种子萌发最活跃时期,产种量高,种子传播是主要的传播方式。将轮叶马先蒿分布面积分为重度、中度和轻度发生区,且随着危害程度的增加,轮叶马先蒿密度和盖度显著增大,而群落的多样性、均匀度和物种丰富度却逐渐降低。轮叶马先蒿种群的生物量占总生物量的比例逐渐增加,禾本科和杂类草的生物量有降低的趋势。针对当地的群落问题,提出了人工和化学防除,同时应建立合理的草地放牧体系,控制和规定合理的草地载畜量,并与围封、补播、施肥等草地改良措施相结合,有效控制轮叶马先蒿的危害和蔓延,改善当地的生态与环境,使当地群落健康、稳定发展。

新疆马先蒿属植物区系特征

马先蒿属（Pedicularis）植物极具观赏价值和药用价值。根据钟补求提出的马先蒿属新系统,新疆马先蒿属植物共有29种,分属6群,14系。新疆分布的马先蒿属植物的特征：①种类少,占国产马先蒿属植物的8.24%,且特有现象不明显;②集中分布于少数群,之形花群（Sigmantha）、直管群（Orthosiphonia）和无枝群（Apocladus）共有25种,占新疆马先蒿属种类的86.21%。拥有最多种的系是无枝群的多毛系,共10种;③该属在新疆的水平分布与新疆境内主要山系相吻合,垂直分布海拔跨度较大,在900～5 180 m;④新疆马先蒿属植物区系与国内邻近省区联系不是很紧密,但与国外某些邻近地区联系紧密,特别是俄罗斯和哈萨克斯坦,共有种分别占新疆马先蒿属植物总数的58.62%和51.72%。