马先蒿属花冠无喙类的花器官发生

对花冠无喙类密穗马先蒿(Pedicularis densispica)和大王马先蒿(P．rex)的花器官电镜扫描发现,两种不同花冠型(无齿和具齿)的马先蒿花部器官发生和发育初期十分相似,表现为明显的单轴对称。2个萼片原基首先发生于花顶的近轴侧位,然后沿花顶边缘向远轴端发育形成--马蹄形结构。密穗马先蒿在近轴中部又出现1枚萼片原基,随后马蹄形结构分化出4枚萼片,并与近轴中部的原基愈合后构成5齿萼片;而大王马先蒿的2齿萼片直接由马蹄形结构发育而成。5枚独立的花瓣原基随后发生,但发育相对滞后;除近轴中部位置1枚空缺外,4枚雄蕊原基与花瓣原基位置呈交互发生;2个心皮原基同时在拱形花顶的近轴和远轴端发生,剩余的花顶形成中间的隔膜,并与2个心皮形成中轴胎座。对马先蒿与金鱼草(Antirrhinum majus)和毛地黄(Digitalis purpurea)花器官发生和发育初期的特征进行了比较,讨论了马先蒿属花冠对称性变化的意义。     

The presence of co-flowering species facilitates reproductive success of Pedicularis monbeigiana (Orobanchaceae) through variation in bumble-bee foraging behaviour

Background and Aims The presence of co-flowering species can alter pollinator foraging behaviour and, in turn, positively or negatively affect the reproductive success of the focal species. Such interactions were investigated between a focal species, Pedicularis monbeigiana, and a co-flowering species, Vicia dichroantha, which was mediated by behaviour alteration of the shared bumble-bee pollinator. Methods Floral display size and floral colour change of P. monbeigiana were compared between pure (P. monbeigiana only) and mixed (P. monbeigiana and V. dichroantha) plots in two populations. Pollinator visitation rates, interspecific floral switching and successive within-plant pollinator visits were recorded. In addition, supplemental pollination at plant level was performed, and the fruit set and seed set were analysed in pure and mixed plots with different densities of P. monbeigiana. Key Results Pollinator visitation rates were dramatically higher in mixed plots than in pure plots. The higher pollinator visitation rates were recorded in both low- and high-density plots. In particular, successive flower visits within an individual plant were significantly lower in mixed plots. Supplemental pollination significantly increased fruit set and seed set of individuals in pure plots, while it only marginally increased seed set per fruit of plants in mixed plots. Conclusions The presence of V. dichroantha can facilitate pollination and increase female reproductive success of P. monbeigiana via both quantity (mitigating pollinator limitation) and quality (reducing geitonogamy) effects. This study suggests that successive pollinator movements among flowers within a plant, as well as pollinator visitation rates and interspecific flower switching, may be important determinants of the direction and mechanisms of interaction between species.     

Corolla wilting facilitates delayed autonomous self-pollination in Pedicularis dunniana (Orobanchaceae)

Structural changes associated with corolla wilting may serve as a mechanism for effecting self-pollination. Low pollinator visitation, high seed production and a corolla that persists after anthesis indicates that Pedicularis dunniana is autogamous. Delayed autonomous self-pollination is facilitated by corolla wilting. Wilting of the upper lip (galea) brought the pollen laden anthers into contact with the stigma resulting in the deposition of self pollen on the stigma. The seed set of flowers either emasculated, or with restrained galeae thus preventing anthers brushing against the stigma, was significantly lower than that of open-pollinated flowers. This demonstrates that autogamy occurs in this species through corolla wilting. Germination experiments indicated that outcross seedlings were more vigorous than selfed seedlings as a result of inbreeding depression. It is likely that autogamy provides reproductive assurance for P. dunniana under conditions of pollinator scarcity.     

Floral ontogeny of Pedicularis (Orobanchaceae), with an emphasis on the corolla upper lip

Pedicularis shows high diversity in its corolla form, however, its floral ontogeny has been rarely investigated. In particular, the development of the highly variable upper lip (galea), three broad morphological types of which (beakless and toothless, beakless and toothed, beaked) can be discriminated, remains unknown. We used scanning electron microscopy to investigate the early stages of floral ontogeny in two beaked species, Pedicularis gruina and P. siphonantha. To compare the developmental processes of the three galea types, three species for each type were investigated. Initiations of floral organs in Pedicularis are consistent. Sepal initiations are successive from the lateral-adaxial primordia, followed by the lateral-abaxial ones (these sometimes missing), then the mid-adaxial one (again sometimes missing). The stamens are initiated prior to the petals, or development of petal primordia may be retarded at the early stages in comparison with that of stamen primordia. Four stamen primordia are initiated simultaneously. The five petal primordia are initiated almost simultaneously. Development processes of the upper lip among the three galea types differ in the expansion rates and directions of the cells of the two lobes and these differences govern whether or not a beak and/or teeth are formed on the upper lip. The floral ontogeny of Pedicularis is close to that of Agalinis, which supports the molecular assignment. Floral monosymmetry of Pedicularis is established at the beginning of sepal initiation and is maintained until flowering. The development of the upper lip provides some clues to the evolution of beaked and/or toothed galeas in Pedicularis.     

马先蒿属植物花冠分化与繁殖适应的研究进展

结合已有的研究报道和作者近年来的工作,对马先蒿属（Pedicularis）植物的花冠多样化成因与繁殖适应特性进行了总结和探讨。通过对该属4种进化花冠型的花器官发生和分化的研究发现,花部各器官在发生和发育初期基本一致,后期上唇形态的分化是导致成熟花形态结构产生较大差异的重要阶段。孢粉学研究认为,花冠类型与花粉萌发孔类型之间具有显著相关性;萌发沟的演化可能与繁殖适应有一定的关系。分子系统学研究表明,多样化的花冠类型在不同的谱系内经过若干次的独立进化而表现出了高度的平行演化（parallelism）。传粉生物学研究证实,该属植物花冠多样化与其主要传粉者熊蜂属（Bombus）昆虫的传粉行为存在较为密切的关系。具有相同（似）花冠类型的马先蒿可能被同种或不同种的熊蜂以相同的方式访问,但在花粉落置位置上存在显著差异,这可能有助于同域分布重叠的物种间在生殖上的机械隔离,而花冠的分化在一定程度上促进了新的物种形成。     

Pollen size-number trade-off and pollen-pistil relationships in Pedicularis (Orobanchaceae)

Current patterns of floral design in Pedicularis must have undergone an evolutionary process of interacting among components of floral traits, and then formed internal relationships among these traits. To detect such correlations, which may provide insight to understand flower evolution, 40 Pedicularis species representing all corolla types of the genus were studied. Results show that, interspecifically, pollen size correlates negatively with pollen number, but positively with pistil length. This suggests that plants evolve an optimal pollen size, which balances the advantages of large pollen size for gametophytic competition against the fecundity disadvantages of fewer pollen grains. In contrast to sex allocation theory, this study does not find a trade-off, but an interspecific positive correlation between pollen and ovule number. This is consistent with the hypothesis that genetic variation for resource acquisition may in part be responsible for the lack of negative correlation between male and female function.This work was supported by the State Key Basic Research and Development Plan, China (Grant No. G2000046804) to YHG. The authors would like to thank Peter K. Endress and two anonymous reviewers for providing critical comments and helpful suggestions, Qing-Feng Wang, Jing-Yuan Wang and Jin-Ming Chen for their helpful suggestions. Shi-Guo Sun, Jing Xia, and Qian Yu are thanked for their assistance in both the field work and laboratory phases of the project.     

Unexpected high divergence in nrDNA ITS and extensive parallelism in floral morphology of Pedicularis (Orobanchaceae)

Internal transcribed spacer (ITS) region sequences of nuclear ribosomal DNA (nrDNA) were used in the phylogenetic reconstruction of Pedicularis, a genus with strong adaptive radiation. Forty-two species representing 12 greges of the genus were all, except P. resupinata, sampled from the Hengduan Mountain region, China. A high level of ITS sequence variation was found among the species distributed in such a small geographical area, which had been rarely reported in other groups. The great ITS divergence in Pedicularis could be explained by a relatively ancient origin and diversification of the genus followed by migration of different floristic components into the Hengduan Mountains, or accelerated rates of molecular evolution in parasitic lineages of Orobanchaceae. In the present ITS phylogeny, almost all the main clades are not consistent with the high hierarchical taxa within Pedicularis, which implies that significant parallel evolution occurred in floral morphology of the genus, and that undue attention has been paid to corolla characters in the intragenus classifications.We thank the two anonymous reviewers for valuable comments and suggestions; Professor Guo You-Hao, Drs. Tan Dun-Yan, Luo Yi-Bo, Bao Ying, Luo Yan, Mr. Mao Jian-Feng and Mr. Qin Wei for their great help in the field collection; Drs. Song Bao-Hua, Wei Xiao-Xin and Miss Sun Ying-Xue for their help in the laboratory work. This study was supported by State Key Basic Research and Development Plan (Grant No. G2000046804) and the National Natural Science Foundation of China (Grant No. 30121003).     

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.     

植物物种的快速鉴定与iFlora: DNA条形码在马先蒿属中的应用

DNA条形码技术就是利用一段较短的标准DNA序列对物种进行快速鉴定。与基于植物外部形态特征的传统分类鉴定方法相比, DNA条形码具有高效、准确,且易于实现自动化和标准化的特点。马先蒿属（Pedicularis L.）植物具对生（轮生）叶的种类70%以上分布在中国,近缘种间形态上非常相似,鉴定较为困难。研究选取马先蒿属具对生（轮生）叶类群43种164份样品,利用叶绿体基因（rbcL、matK、trnH psbA）和核基因（ITS）条形码片段,采用建树法和距离法检验4个条形码对这些物种的鉴定效果。结果表明,ITS片段用于建树法和距离法的鉴别率分别为81.40%和89.57%,其鉴别率高于3个叶绿体基因片段和任一基因片段的组合条码。另外,利用ITS成功解决了一些疑难种的分类问题。DNA条形码在马先蒿属研究中的实用性为新一代植物志（iFlora）实现物种的快速和准确鉴定提供了有力支持,并能为分类学、生态学、进化生物学、居群遗传学和保护遗传学等分支学科的研究提供重要信息。     

Honeybees enhance reproduction without affecting the outcrossing rate in endemic Pedicularis densispica (Orobanchaceae)

There has been substantial debate in recent years surrounding the impact of introduced honeybees on native biota. This study reports on an investigation of Pedicularis densispica, a subalpine annual herb endemic to Southwest China, in an attempt to determine the impact of introduced domestic honeybees on pollen dispersal and thus on their reproductive success and mating system. Honeybees were introduced into the study site in 2004, and a sudden seasonal pollinator shift from bumblebees to honeybees was observed. Intra- and inter-plant visits by different pollinators were recorded in the field in 2003 and 2004. Fruit and seed sets prior to and after the pollinator shift were measured. Experimental pollinations were performed to characterize the breeding system. Outcrossing rates at the seed stage were estimated for both years using RAPD markers. Our results indicated that honeybees foraged between plants more frequently than bumblebees did. Our results also revealed that the introduction of honeybees significantly enhanced reproductive success. However, no significant difference was detected between the outcrossing rates due to bumblebee and honeybee pollination. P. densispica was almost completely outcrossing ( T(m) = 0.956 and 0.967, respectively in 2003 and 2004) but partially self-compatible. This study presents the first report of the outcrossing rate in the genus pedicularis and reveals a limited influence of pollination on the mating system in P. densispica. The pollinator shift did not reduce reproductive success of the plants and honeybees may be used to augment pollinator services for nectariferous P. densispica.     

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.     

Highly efficient pollination by bumblebees ensures seed production in Pedicularis lachnoglossa (Orobanchaceae), an early-flowering Himalayan plant

Pedicularis (Orobranchaceae) is a common high altitude genus of the Himalayas that may be affected by pollination limitation.Using Pedicularis lachnoglossa from Yulong (Jade Dragon) Snow Mountain in Li...     

Highly efficient pollination by bumblebees ensures seed production in Pedicularis lachnoglossa (Orobanchaceae), an early‐flowering Himalayan plant

Abstract Pedicularis (Orobranchaceae) is a common high altitude genus of the Himalayas that may be affected by pollination limitation. Using Pedicularis lachnoglossa from Yulong (Jade Dragon) Snow Mountain in Lijiang (Yunnan Province, southwest China), we investigated the effects of high altitude habitats on the process of pollination and seed production. Floral biology, pollinator foraging behavior, breeding system, and pollination efficiency were examined using observation and exclusionary techniques. Pedicularis lachnoglossa was found to be entomophilous and exclusively pollinated by Bombus friseanus and B. yunnanicola. Our results indicated that pollination limitation in P. lachnoglossa was not significant. Under open pollination, approximately 80% of flowers were successfully pollinated and developed to fruits, and about 38% of ovules developed to mature seeds. Bumblebee pollination is highly precise and efficient in P. lachnoglossa, because its flowering phenology and floral characters enhance the foraging of bumblebees on flowers. This study supports that animal pollination plays a crucial role in the outbreeding of the early flowering Pedicularis. The evolution of floral specification in Pedicularis has the advantages of adaptation to bumblebee pollination in adverse high altitude habitats.     

西藏列当科新记录属——豆列当属

在西藏八宿县然乌镇安久拉山垭口进行植物多样性调查时,发现一种寄生植物,经过查阅文献、核对模式标本,最终鉴定为列当科(Orobanchaceae)豆列当属(Mannagettaea)植物矮生豆列当(Mannagettaea hummelii H. Smith)。该种分布在中国及俄罗斯(萨彦岭地区),国内记载仅分布在甘肃、青海、四川;西藏为新记录属。该发现丰富了西藏的植物区系,同时将矮生豆列当分布海拔提升至4 459 m。凭证标本现存于中国科学院昆明植物研究所标本馆(KUN)。     

Floral nectary morphology and evolution in Pedicularis (Orobanchaceae)

Intricate associations between floral morphology and pollinator foraging behaviour are common. In this context, the presence and form of floral nectaries can play a crucial role in driving floral evolution and diversity in flowering plants. However, the reconstruction of the ancestral state of nectary form is often hampered by a lack of anatomical studies and well‐resolved phylogenetic trees. Here, we studied 39 differentially pollinated Pedicularis spp., a genus with pronounced interspecific variation in colour, shape and size of the corolla. Anatomical and scanning electron microscopy observations revealed two nectary forms [bulged (N = 27) or elongated (N = 5)] or the absence of nectaries (N = 7). In a phylogenetic context, our data suggest that: (1) the bulged nectary should be the ancestral state; (2) nectaries were independently lost in some beaked species; and (3) elongated nectaries evolved independently in some clades of beakless species. Phylogenetic path analysis showed that nectary presence is indirectly correlated with beak length/pollinator behaviour through an intermediate factor, nectar production. No significant correlation was found between nectary type and nectar production, beak length or pollinator behaviour. Some beaked species had nectary structures, although they did not produce nectar. The nectary in beaked species may be a vestigial structure retained during a recent rapid radiation of Pedicularis, especially in the Himalaya–Hengduan Mountains of south‐western China. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, 178 , 592–607.     

中国假野菰属(列当科)一新记录种——泰国假野菰

报道了中国假野菰属(列当科)一新记录种——泰国假野菰(Christisonia siamensis Craib)。结果表明:该种与假野菰(C.hookeri Clarke)的主要区别是花萼黄色或白色,有时暗紫色,具有独特的三角状花萼齿;花冠裂片紫色,下唇裂片中部有一黄色斑点并延伸至花冠筒内侧;花丝光滑,花药一室,粘合,通常明显有距,距的基部具圆锥形的突起;顶端有开裂的毛孔。     

Bumblebee pollination of Cypripedium macranthos var. rebunense (Orchidaceae); a possible case of floral mimicry of Pedicularis schistostegia (Orobanchaceae)

 Nectarless flowers of Cypripedium macranthos var. rebunense are pollinated by only queen Bombus pseudobaicalensis, which also pollinates nectar-producing flowers of Pedicularis schistostegia. Our previous study (Sugiura et al. 2001) suggested that they form a floral mimicry system: (1) Flowering phenology of both plants overlapped greatly. (2) Cypripedium occurred with lower frequency relative to Pedicularis. And (3) in a mixed stand of both plants, foraging bumblebees were sometimes confused between the mimic and model flowers. The present study clarified the system with new evidence. (4) Flower colour of Cypripedium and Pedicularis would be similar within the range of a bumblebee's visual spectrum. And (5) both species largely overlapped in spatial distribution. Based on these findings, we discuss how C. macranthos var. rebunense differs in pollination mechanism from other congeneric species, especially C. calceolus. Received April 23, 2002; accepted August 23, 2002 Published online: November 28, 2002 Addresses of the authors: Naoto Sugiura (e-mail: sugiura@aster.sci.kumamoto-u.ac.jp), Department of Environmental Science, Faculty of Science, Kumamoto University, Kumamoto 860-8555, Japan. Masashi Goubara, United Graduate School of Agricultural Sciences, Tottori University, Tottori 680-8553, Japan. Kenji Kitamura, Division of Environmental Biology, Faculty of Life and Environmental Science, Shimane University, Mastue 690-8504, Japan. Ken Inoue, Biological Institute and Herbarium, Faculty of Science, Shinshu University, Matsumoto 390-8621, Japan.