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1.
The transition from biotic to wind pollination and the consequencesof this transition for the evolution of dioecious breeding systems wereinvestigated in Schiedea and Alsinidendron(Caryophyllaceae: Alsinoideae), genera endemic to the Hawaiian Islands. The potential for wind pollination was studied for five species ofSchiedea using a wind tunnel. Morphological correlates of windpollination for these species were then used to infer the presence orabsence of wind pollination in the remaining Schiedea species. Hermaphroditic Alsinidendron and Schiedea species,which occur in mesic to wet forests, or less commonly in dry habitats,show little or no indication of wind pollination. These species had lowpollen:ovule ratios, large relative pollen size, diffuse inflorescences,substantial nectar production in several cases, and appear to bebiotically pollinated or autogamous. Sexually dimorphic species, whichall occur in dry habitats, are wind pollinated, based on wind tunnelresults or morphological adaptations indicating the potential for windpollination. These adaptations include high pollen:ovule ratios, smallpollen size, moderately to highly condensed inflorescences, and reducednectaries and nectar production. Shifts to wind pollination anddimorphism are strongly correlated in Schiedea, suggesting theclose functional relationship of the twophenomena.  相似文献   

2.
CHINNAPPA, C. C, GIFFORD, D. J. & RAMAMORRTHY, J., 1992. Studies on the Stellaria longipes complex (Caryophyllaceae): relationships among the species based on seed protein profiles. The protein profiles of nine genera of the family Caryophyllaceae show distinct patterns. Within the genus Stellaria , six species were studied. The four North American species show more or less similar profiles, while the two European species have quite different patterns. There are some indications to suggest that the polyploid species, 5. longipes , is closely related to diploid S. longifolia and S. porsildii. The seed protein profiles of these species support the view that 5. longipes might have originated from hybridization between the two diploid species.  相似文献   

3.
A re-evaluation of Minuartia graminifolia has been undertaken based on comparative morphological studies. M. graminifolia subsp. rosani (an endemic of the south-central Apennines and Sicily) and subsp. hungarica (an endemic of the Banat region of Romania) are accepted infraspecific taxa. M. graminifolia subsp. hungarica is lectotypified. M. graminifolia subsp. clandestina is confirmed for Italy; the taxon is neotypified. The type subspecies is considered an endemic to the east-central Alps. Keys to the species of Minuartia ser. Graminifoliae and to the subspecies of M. graminifolia are provided.  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 419–432.  相似文献   

4.
Study of floral anatomy, micromorphology, palynology and onotogeny has revealed new characters for phylogenetic analysis in the genus Scleranthus . Cladistic analysis of these characters, along with those previously available, suggests that the genus consists of Eurasian/Mediterranean and Australasian sister clades. Gynoecial morphology and development are closely similar in all species, suggesting the genus is monophyletic despite its disjunct northern and southern hemisphere distribution. Variation in pollen:ovule ratios and their implications for the evolution of Scleranthus species are also discussed and it is concluded that a range of breeding strategies intermediate between autogamy and xenogamy exists in the genus. Single-stamened species of Scleranthus are likely to be obligate autogams, despite their comparatively high pollen:ovule ratios in relation to autogamic species of other genera.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 140 , 15–29.  相似文献   

5.
Ayşe Kaplan 《Biologia》2008,63(1):53-60
The Pollen morphology of 13 taxa 11 of which are endemics belonging to Paronychia Miller (Caryophyllaceae) viz., P. agryloba, P. angorensis, P. arabica subsp. euphratica, P. carica, P. cataonica, P. chinonea, P. condensata, P. davisii, P. dudleyi, P. galatica, P. kurdica subsp. kurdica, P. kurdica subsp. montis-munzur and P. mughlaei from Turkey has been investigated by light (LM) and scanning electron microscopy (SEM). LM observations show that pollen grains are usually radially symetrical, isopolar, pantoporate, polygonal (6-gonal) or polygonal-spheroidal. Tectum is psilate or punctate. Tectal surface sparsely-densely spinulose. The numbers of pores are between 6 and 12. On the basis of pollen sizes, P. davisii was the biggest pollen type (23.45 μm) and P. kurdica subsp. kurdica (16.2 μm) was the smallest pollen types. According to exine sculpturing, pollen size and spinule numbers per 1 μm2, three pollen types were distinguished.  相似文献   

6.
Fabio Conti 《Plant biosystems》2013,147(2):191-194
ABSTRACT

A new Minuartia was discovered in Cilento (S. Italy). The species described here as M. moraldoi belongs to the ser. Graminifoliae.  相似文献   

7.
8.
中国栎属植物花粉形态及其系统学意义   总被引:5,自引:0,他引:5  
曹明  周浙昆 《广西植物》2002,22(1):14-18
从系统学分类学的角度出发 ,对国产栎属 31个种的花粉进行了光学显微镜和扫描电镜观察。研究结果表明栎属的花粉萌发孔对该属的系统与分类无太大的参考价值 ;但栎属的花粉纹饰有颗粒状、聚颗粒状两种主要类型 ,具有重要的系统学分类学价值。花粉形态的研究结果支持将栎属植物划分为常绿类与落叶类的观点 ;栎属巴东栎组植物的花粉纹饰在种间存在分化 ,花粉形态的研究结果支持将巴东栎组至少划分为两个不同类群的观点 ;在佐以其他证据的情况下 ,栎属植物的花粉纹饰还具有重要的分类学价值  相似文献   

9.
四川前胡属的花粉形态及系统学意义   总被引:8,自引:3,他引:8  
通过光学显微镜和扫描电镜观察了前胡属 Peucedanum L.7种植物的花粉形态 .研究结果表明 :该属花粉为三棱长球形 ;三孔沟 ,边孔 ;外壁两层 ,层次分明 .根据花粉形态可归为 :矩形型和赤道收缩形型二个类型 ,其演化趋势为矩形型→赤道收缩形型 .研究结果支持了关于前胡属在伞形科中是一个较自然和较进化的类群的观点 .本文从孢粉学角度还初步分析了该属的属下系统 ,为该属的系统学研究提供基础资料  相似文献   

10.
This study focuses on karyological investigation of four taxa of Dianthus (Caryophyllaceae) including D. crossopetalus, D. orientalis subsp. stenocalyx, D. orientalis subsp. gorganicus, and Dianthus sp. distributed in Northeast of Iran. The karyotype asymmetry/symmetry was evaluated using two methods: 1) CVCL (coefficient of variation of chromosome length) and CVCI (heterogeneity of the centromeric index); and 2) MCA (mean centromeric asymmetry). The karyotype asymmetry was also used to investigate the relationships among the taxa. Results obtained from the current study revealed that there are two different ploidy levels (2n = 2x = 30 and 2n = 4x = 60) among the investigated taxa. The indices CVCL and MCA described karyotype asymmetry correctly based on variation in chromosome length. Diagram of CVCL vs. MCA seems to be appropriate for karyological delimitation and taxonomic relationships among the Dianthus taxa under study. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

11.
The genus Adeonella Busk (1884) comprises 41 species, 15 of which are considered to be new to science. Adeonella lichenoides (Lamarck) is regarded as the senior synonym of A. platalea (Busk) (= A. polymorpha Busk), the type species of the genus. Adeonella is distributed throughout the Indo-West Pacific realm, the Mediterranean, and the South Atlantic Ocean. Its highest diversity is found off the east coasts of southern Africa. Thirty-one species (15 new to science) are described and illustrated, morphology and geographical distribution are discussed and a key is provided to all recognized species.  相似文献   

12.
Buide ML 《Annals of botany》2006,97(2):289-297
BACKGROUND AND AIMS: The floral display influences the composition of pollinators interacting with a plant species. Geographic and temporal variation in pollinator composition complicates the understanding of the evolutionary consequences of floral display variation. This paper analyses the relationships between Silene acutifolia, a hermaphroditic perennial herb, and its pollinators, based on field studies in the north-west of Spain. METHODS: Studies were conducted over three years (1997-1999). Firstly, the main pollinators of this species were determined for two years in one population. Secondly, pollen limitation in fruit and seed production was analysed by supplementary hand pollinations, and counting the pollen grains and tubes growing in styles for two different-sized populations. Finally, the effect of flower size and number on the rate of visitation and total seed number was examined for 15 marked plants. RESULTS AND CONCLUSIONS: The primary pollinators were long-tongued insects, including Hymenoptera, Lepidoptera and Diptera, but the composition and visitation frequencies differed between years. Pollen limitation occurred in one of the years of study. There was between-population variation in the number of pollen grains and pollen tubes found in styles, suggesting pollen limitation in one population. Overall, pollinators visited plants with more open flowers more frequently, and pollinated more flowers within these plants. Conversely, petal and calyx sizes had no effect on insect visitation. Plants with higher rates of visits produced higher number of seeds, suggesting that pollinator-mediated limitation of seed and fruit production may be important in some years.  相似文献   

13.
A specimen collected in southern Tibet in 1928, hitherto identified only as "Arenanu sp.", is found to represent a new species of the subgenus Odontostemma . The new species resembles A. littledalei , the species that forms the basis of the monotypic genus Gooringia , characterized by a dwarf habit, a tetramerous perianth and only two or three stamens. Several other species of Arenaria subgenus Odontostemma resemble A. littledalei in habit and one ( A. saginoides ) is tetramerous, but hitherto none has been found with its extremely reduced androecium. The new species has an identical androecium to A. littledalei and its discovery leaves no doubt that Gooringia should not be recognized taxonomically at any rank. The new species is described as A. pharensis McNcill & Majumdar and a table compares its diagnostic features with those of A. littledalei and five other dwarf Arenaria species of sibgrnus Odontostemma from the mountains of Sikkim, Tibet, Yunnan and Tsinghai.  相似文献   

14.
Phylogenetic relationships of the subgenera of Exorista Meigen (Diptera: Tachinidae) are inferred from morphological data. Our results show that the genus Exorista is not monophyletic and that members of the subgenus Spixomyia Crosskey are divided into two clades. Each subgenus is redefined based on male and female morphological features. The Japanese species of Exorista are revised and classified into five subgenera: Adenia Robineau‐Desvoidy, Exorista Meigen, Podotachina Brauer and Bergenstamm, Ptilotachina Brauer and Bergenstamm, and Spixomyia Crosskey. Thirteen species are recognized, including two newly recorded species, Exorista (Adenia) cuneata Herting and Exorista (Spixomyia) lepis Chao. Exorista cantans Mesnil is transferred to the subgenus Podotachina from Spixomyia.  相似文献   

15.
Evolution of dimorphic breeding systems may involve changes in ecophysiological traits as well as floral morphology because of greater resource demands on females. Differences between related species suggest that ecophysiological traits should be heritable, and species with higher female frequencies should show greater sexual differentiation. We used modified partial diallel crossing designs to estimate narrow-sense heritabilities and genetic correlations of sex-specific ecophysiological and morphological traits in closely related gynodioecious Schiedea salicaria (13% females) and Schiedea adamantis (39% females). In S. salicaria, hermaphrodites and females differed in photosynthetic rate and specific leaf area (SLA). Narrow-sense heritabilities were significant for stomatal conductance, SLA and inflorescence number in hermaphrodites, and for SLA and inflorescence number in females. Schiedea adamantis had no sexual dimorphism in measured traits; stomatal conductance, stem number and inflorescence number were heritable in females, and stem number was heritable in hermaphrodites. In both species, significant genetic correlations of traits between sexes were rare, indicating that traits can evolve independently in response to sex-differential selection. Significant genetic correlations were detected between certain traits within sexes of both species. Low heritability of some ecophysiological traits may reflect low additive genetic variability or high phenotypic plasticity in these traits.  相似文献   

16.
Inbreeding depression and selfing rates were investigated in Schiedea membranacea (Caryophyllaceae), a hermaphroditic species endemic to the Hawaiian Islands. Most theoretical models predict high inbreeding depression in outcrossing hermaphroditic species and low inbreeding depression in inbreeding species. Although high outcrossing rates and high levels of inbreeding depression are characteristic of many species of Schiedea, self- fertilization is common among relatives of hermaphroditic S. membranacea, and high selfing rates and low levels of inbreeding depression were predicted in this species. Sixteen individuals grown in the greenhouse were used to produce selfed and outcrossed progeny. Inbreeding depression, which was evident throughout the stages measured (percentage viable seeds per capsule, mean seed mass, percentage seed germination, percentage seedling survival, and biomass after 8 mo), averaged 0.70. Inbreeding depression among maternal families varied significantly for all measured traits and ranged from −0.12 to 0.97. Using isozyme analysis, the multilocus selfing rate varied from 0.13 to 0.38 over 4 yr. Contrary to the initial prediction of high selfing and low inbreeding depression based on phylogenetic relationships within Schiedea, low selfing rates and high levels of inbreeding depression were found in S. membranacea. These results indicate that outcrossing is stable in this species and maintained by high levels of inbreeding depression.  相似文献   

17.
Abstract Levels of selfing and resource allocation patterns were investigated in Schiedea salicaria (Caryophyllaceae), a gynodioecious species with high levels of inbreeding depression and nuclear control of male sterility. Selfing levels were higher in hermaphrodites than females, especially when adjusted for early acting inbreeding depression. The sexes of S. salicaria were similar in most allocation patterns including number of flowers and capsules per inflorescence, seeds per flower, and seed mass. Seeds produced by females had higher levels of germination than seeds of hermaphrodites, a likely result of high selfing levels and the expression of inbreeding depression in the progeny of hermaphrodites. Invasion of females in populations of S. salicaria is probably related to the expression of inbreeding depression at germination and in later life history stages. Comparisons with related species of Schiedea that also have nuclear control of male sterility suggest that reallocation of resources in hermaphrodites to male function occurs as females increase in frequency, but that resource reallocation is not important for the success of females when they first invade populations.  相似文献   

18.
Variations in seed micromorphology of 64 taxa of Arenaria and allied genera were examined using scanning electron microscopy (SEM) in order to evaluate their diagnostic value for systematic studies in the genus and providing additional evidence on delimitation of natural groups. Significant diversity was found in seed coat morphology both among and within genera. Size, color, and shape of seeds appear to be of low importance at species level but provide useful evidence at generic rank. Cerastium and Stellaria are well distinguished from Arenaria by serrate seed margins and solid columellae on testa cells. The sculpturing pattern renders most characters potentially applicable in taxonomy and phylogeny assessment in Arenaria. The studied taxa show four basic types of sculpturing, viz. colliculate, rugose, papillate, and smooth. The colliculate type which is characteristic for the core group of Arenaria (A. subg. Arenaria) can be further divided into five subtypes. The smooth seed surface with indistinct cell boundaries represents a synapomorphy for A. subg. Leiosperma, whereas the winged seeds along with rugose surface characterize subg. Odontostemma. Otherwise seed micromorphology rarely provides adequate evidence for separation of natural groups, especially at sectional rank. We hypothesize that the seeds are highly polymorphic in certain groups of taxa showing recent adaptive radiation, such as the annual species of Arenaria, and do not provide strong support for natural groups within the genus.  相似文献   

19.
20.
Pollen morphology of 58 species from 17 putative genera of the tribe Atripliceae (Chenopodiaceae) was investigated using light (LM) and scanning electron microscopy (SEM). Morphological variation was analyzed based on a dense sampling of the subtribes Atriplicinae and Eurotiinae, including many of the species in the two largest genera: Atriplex and Obione. The pantoporate pollen grains of Atripliceae are characterized by their spheroidal or subspheroidal shape, flat or moderately vaulted mesoporia with 21–120 pores, tectum with 1–8 spinules and 5–28(?38) puncta per?µm2, and 1–13 ectexinous bodies bearing 1–7 spinules each. Taxonomic relevance of the most important pollen morphological characters is discussed (pollen diameter, pore number, pore diameter, interporal distance, spinule and puncta density and ratio, number of ectexinous bodies, and their spinules). Pollen morphological data support the exclusion of Suckleya from the tribe and the recognition of subtribe Eurotiinae, but suggest that it needs to be reviewed. Pollen does not support generic recognition of Atriplex, Neopreissia and Obione and infrageneric subdivisions as currently recognized, and suggests the need to review them. Smaller or monotypic genera, such as Axyris, Ceratocarpus, Endolepis, Krascheninnikovia, Microgynoecium, Proatriplex and Spinacia have distinctive pollen morphological characters that support their generic status. Grayia needs to be reevaluated; although its two species are distinct from all the other species in the study, there are notable differences between each of them, and this suggests they may not form a natural group. Multivariate techniques were employed to investigate if there are discrete patterns of variation within Atripliceae. Principal Component Analyses (PCA) weakly differentiates four groups based on variation in pore number, puncta density per?µm2, and ratio between spinule and puncta density per?µm2; species of Ceratocarpus, Haloxanthium, Krascheninnikovia, Manochlamys, Microgynoecium, Spinacia, and some species of Atriplex and Obione are isolated. Preliminary results indicate that pollen data are potentially useful in the classification of the tribe, and further studies will be of taxonomic value.  相似文献   

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