滇西北马先蒿属传粉生物学的初步研究

对云南西北部的中甸和德钦高山地区４种马先蒿属（ＰｅｄｉｃｕｌａｒｉｓＬ．）植物的传粉生物学进行了观察。晚夏开花的马先蒿与传粉熊蜂（ＢｏｍｂｕｓＬａｔｒ．）的出现在物候上有一定的相关性。其中短管、无喙、无蜜腺的肉根马先蒿（Ｐ．ｒｏｙｌｅｉＭａｘｉｍ．）和茨口马先蒿（Ｐ．ｔｓｅｋｏｕｅｎｓｉｓＢｏｎａｔｉ）是由熊蜂工蜂震动花粉、背触式传粉,这与其花冠类型的较原始性有关;长管、具喙、无蜜腺的斑唇马先蒿（Ｐ．ｌｏｎｇｉｆｌｏｒａｖａｒ．ｔｕｂｉｆｏｒｍｉｓ（Ｋｌｏｔｚ．）Ｔｓｏｏｎｇ）和云南长管马先蒿（Ｐ．ｓｉｐｈｏｎａｎｔｈａＤｏｎ．ｖａｒ．ｄｅｌａｖａｙｉ（Ｆｒａｎｃｈ．）Ｔｓｏｏｎｇ）通过熊蜂工蜂震动花粉、腹触式传粉。长管类马先蒿在植株相对矮小的情况下,通过较长的花冠管具喙向外伸出以实现授粉,这可能是与其传粉熊蜂协同进化的结果。     

马先蒿属6个种的核型与进化研究

分析和报道了马先蒿属分布于青藏高原东北部６个特有种的核型,并根据核型及其有关参数,分析和比较了该６种马先蒿核型的不对称性和相对进化程度。６个种的体细胞染色体数目都是２ｎ＝１６。核型分别为：绵穗马先蒿Ｐ．ｐｉｌｏｓｔａｃｈｙａ Ｍａｘｉｍ．,核型公式Ｋ（２ｎ）＝１６＝４ｍ＋１２ｓｍ,染色体相对长度组成２Ｌ＋６Ｍ２＋６Ｍ１＋２Ｓ,核型不对称系数Ａｓ·Ｋ＝６５．２９％,属于２Ａ型;青海马先蒿Ｐ．ｐｒｚｅ     

POLLINATION INTERACTIONS IN SYMPATRIC DICENTRA SPECIES

The pollination of a large mixed population of Dicentra canadensis and D. cucullaria was studied in a beech-maple forest in southwestern Ohio. Analyses of pollinator frequencies and species, pollinator behavior, sugar components and concentrations in nectar, corbicular pollen loads carried by pollinators, spectral reflectance from corollas including ultraviolet reflectance, fragrance, blooming phenology, insect-related fertility, and hybridization potentials suggested that these sympatric Dicentra species are reproductively isolated by internal mechanisms but not by external barriers to hybridization. Both species were exclusively and obligately dependent upon queen bumblebees for their pollination unlike other members of the spring ephemeral flora to which they belong. The occurrence of one or both species in one area is considered primarily the result of their adaptive preference for different edaphic and possibly climatic situations and not the consequence of competitive exclusion by pollinator behavior.     

POLLINATION OF TWO SYMPATRIC SPECIES OF DALECHAMPIA (EUPHORBIACEAE) IN SURINAME BY MALE EUGLOSSINE BEES

Dalechampia brownsbergensis and D. fragrans co-occur in Suriname, and both are pollinated by fragrance-collecting male euglossine bees. Dalechampia brownsbergensis appears to bloom year-round and is pollinated by relatively few species of bees, including Euglossa tridentata and E. gaianii. In contrast, D. fragrans appears to bloom from late October through early December and is visited and pollinated by at least 13 species of euglossines. Field observations of pollination indicated that the two species did not share pollinators. However, when the flowers of D. fragrans were “transplanted” into a population of D. brownsbergensis, the main pollinator of D. brownsbergensis also visited the flowers of D. fragrans. The pollinators of D. fragrans, however, did not visit the flowers of D. brownsbergensis. Partial sharing of pollinators may have only a small negative impact on the two sympatric plant species at this site because they flower simultaneously only part of the year, and they are often spatially separated from one another.     

THE POLLINATION ECOLOGY OF PEDICULARIS ON MOUNT RAINIER

Six native species of Pedicularis in Mount Rainier National Park in Washington State were studied for their reproductive relationships with animal pollinators. Cinematographic and stereophotographic records revealed pollination of the nectariferous P. bracteosa and P. rainierensis by upright, nectar-foraging queens and workers of five bumblebee (Bombus Latr.) species and by inverted workers scraping pollen from anthers concealed within the corolla galea. The nectarless, rostrate flowers of P. contorta, P. groenlandica, P. ornithorhyncha, and P. racemosa were pollinated by pollen-foraging workers and occasional queens virbrating pollen from concealed anthers. Insect exclosure methods revealed complete absence of fruiting in the absence of insects, and pollinator collections further indicate obligate dependence of the plants upon bumblebees for their sexual reproduction. Analysis of corbicular pollen loads from pollinators suggested that pollinator species are not monolectic but that individual pollinators range from monolectic to polylectic. Measurements indicated limited correlations between lengths of corolla tubes and tongues of nectar-foraging insects. Each nectarless Pedicularis species occupied a different, specific habitat, but P. bracteosa and the endemic P. rainierensis were sympatric in part. Each species had a unique spectral reflectance pattern from the corolla. Proximity of habitats and overlap of blooming periods of all Pedicularis species eliminate the possibility of contemporary geographic or phenological reproductive isolation. It is suggested that behavioral interactions of the plants and their insect pollinators may have been instrumental in the past in reproductively isolating these species, hybrids of which are unknown.     

REPRODUCTIVE ECOLOGY OF CARYA (JUGLANDACEAE): PHENOLOGY,POLLINATION, AND BREEDING SYSTEM OF TWO SYMPATRIC TREE SPECIES

Observations and experiments on both shagbark (Carya ovata; 2n = 32) and mockernut (C. tomentosa; 2n = 64) hickories in a New Jersey forest were performed over a 2-year period to determine the mechanisms operating both to maintain reproductive fidelity and to regulate fruit initiation. Phenological observations indicated significant differences between the species for almost all vegetative and reproductive characters examined; however, a large amount of overlap was also observed. Pollination experiments indicated that pollen limitation is not a significant factor in reducing fruit set in these anemophilous species. Pollen-ovule ratios ranged from 1 to 25 × 10⁶. Pollen was 80–90% viable at time of shedding. The large surface area of vegetative structures (e.g., leaves) at the time of pollination may retard the flow of pollen into and out of the canopy and thus increase self-pollination. A full diallel cross, replicated 5 times, was made among 8 trees (4 trees of each species) to characterize combining ability and compatibility relationships. All trees were found to be both geitonogamous and xenogamous to varying degrees. A high frequency of putative interploidal cross-compatibility was also observed. Fruits from these interspecific crosses were found to be germinable. Observations on individual trees suggested that dichogamy may help to reduce selfing and promote outcrossing in this breeding system. While most trees exhibited a temporal separation of genders, the trait was found to be quite plastic (i.e., trees switched between protogyny and protandry between years). Pistillate flowers were receptive for all trees within a species during the same general time period; however, pollen shedding varied considerably among trees and between years. Both species appear to be utilizing a broad array of mechanisms in order to maintain reproductive fidelity and adequate fruit set.     

马先蒿属一新种

本文发表了马先蒿属一新种,即稻城马先蒿Pedicularis daochengensis H. P. Yang。     

云南短冠草属一新种

孟连短冠草新种图１Sopubia menglianensis Y. Y. Qian sp. nov. Fig. 1Species affinis S. trifidae Buch.-Ham., sed foliis 1-3.5 cm longis, omnino simpliciis,pubescentibus, bracteis pedicello longioribus, calycis lobis longioribus quam latioribus,calycibus et corollae lobis rubro-glandlosis, capsulis oblongo-ovoideis, calycibus longioribusdiffert.Herba perennis; rhizoma breve erectum; caulis 1-3, 22-70 cm altus, superne ramosus,raro 3-ramis verticillatis, striatus, pubescens. Folia opposita vel s…     

THE TAXONOMIC IMPLICATIONS OF POLLEN MORPHOLOGY IN SOME SOUTH AMERICAN SPECIES OF MIMULUS (SCROPHULARIACEAE)

The pollen grains of South American hexaploid representatives of the Mimulus glabratus complex, section Simiolus, and M. bridgesii, a South American species sometimes included in this complex and sometimes in section Paradanthus, were examined by light and scanning electron microscopy. Mimulus bridgesii has (6-) 4–5-zoniaperturate grains nearly identical to those observed in a complex of species in section Paradanthus. South American members of the M. glabratus complex (M. bridgesii excluded) have the irregularly synaperturate, ± spiraperturate pollen typical of section Simiolus (sensu Grant). Treatment of M. bridgesii as a palynologically aberrant member of section Simiolus is not supported by what is known about the evolution of pollen types in Mimulus and the evolution and dispersal of the M. glabratus complex.     

VARIATION OF SEX ALLOCATION AMONG EIGHT TAXA OF THE MIMULUS GUTTATUS SPECIES COMPLEX (SCROPHULARIACEAE)

Characters related to sex allocation and the mating system were studied in eight California taxa of the Mimulus guttatus complex: M. guttatus, M. nasutus, M. glaucescens, M. Tilingii, M. nudatus, M. laciniatus, M. platycalyx, and M. micranthus, ranked in approximate decreasing levels of outbreeding. Dry weights and lengths of floral parts, pollen and ovule number, and timing of stigmatic closure were measured on plants in the growth chamber. As percent of total flower weight, allocation to stamens and corollas was lowest in M. micranthus (28%), intermediate in M. platycalyx, M. Tilingii, and M. laciniatus (50%), and high in other taxa (60%). Among M. micranthus, M. platycalyx, and M. laciniatus, pollen–ovule ratios ranged from 3.9 to 12.0; ratios for other taxa were 19.3 to 26.6. Taxa with increased male biomass allocation generally show increased outcrossing and increased P/O ratios. Stigma-anther separation and closure of stigma lobes upon touch were positively correlated with outcrossing ratios, P/O ratios, and male allocation. Isozyme variation indicates the inbreeding taxa have been independently derived; thus, these associations of maleness with outbreeding are significant trends in the Mimulus guttatus complex.     

马先蒿属两新种

多年生草本,干时多少变黑,近于无毛。根多分枝,细瘦。茎常长达40厘米,柔弱,斜升或铺散。叶下部的对生,但上部的互生,叶柄纤细,长达2厘米;叶片卵形至椭圆形,长1-2厘米,膜质或纸质,上面无毛,下面被白色肤屑状物,羽状全裂,裂片约4-5对,卵形至长圆形,长2-6毫米,边缘常有反卷的重锯齿。花腋生,很疏远,花梗氏5-10毫米,尊圆筒形,膜质,长约8-9毫米,前方开裂达1/2,被疏毛,萼齿3枚,后方的1枚较小,钻状,其余的在中部狭缩成柄状,上部叶状扩展,边缘强反卷;花冠红色,长约3-3.5厘米,管长2-2.6厘米,外面疏被柔毛、盔直立部分长6毫米,喙长约7毫米,狭细,卷曲成半坏状,下唇长9毫米,宽13毫米,边缘被缘毛,中裂片较小,端微凹;花丝全部无毛;花柱稍伸出。蒴果为增大的宿萼所包,卵圆形,多少扁平,长约12毫米。花果期8-9月。     

COMPARATIVE SPERMATOLOGY OF FOUR SYMPATRIC SPECIES OF SIPHONARIA (PULMONATA: BASOMMATOPHORA)

The fine structure of the modified sperm and spermatogenesisof four sympatric species of Siphonaria is described. The morphologyof the sperm of all species is very similar. The head, whichis about 6 µm long, is composed of a nucleus with fibrouschromatin capped by an acrosome (about 1 µm long) comprisedof an acrosomal pedestal and apical vesicle. The midpiece hasa mitochondrial derivative which surrounds a single glycogenhelix, posterior to which is a glycogen piece. Although differencesbetween each species exist, the value of sperm morphology forpurposes of taxonomy in this genus is questioned. Comparisonwith other basommatophorans however suggests that sperm morphologymay be of value at a higher taxo-nomic level. The morphologicalchanges that occur during spermatogenesis are similar to thosedescribed for other molluscs with modified sperm, except thatduring early spermiogenesis the Golgi body and smooth endoplasmicreticulum become highly developed. This proliferation of theSER and Golgi occurs at the same time as elongation of the spermatid.Throughout spermatogenesis, the germ cells are closely associatedwith a somatic cell which, because of structural similaritieswith the somatic cell of mammalian seminiferous epithelium,has been termed a Sertoli cell. After the spermatids have beenreleased from the Sertoli cells of the testis, maturation continuesin the hermaphrodite duct where the acrosome reaches its finalsize and glycogen accumulates in the glycogen compartment ofthe mid-piece. (Received 25 April 1990; accepted 1 September 1990)     

THE AERODYNAMICS OF POLLEN CAPTURE IN TWO SYMPATRIC EPHEDRA SPECIES

Wind-tunnel analyses of the behavior of airborne pollen around ovules of two Ephedra species (E. trifurca and E. nevadensis) indicate that at certain airflow speeds (0.5 m/sec and 1.0 m/sec) each species is capable of biasing pollination in favor of conspecific pollen. A computer procedure was designed to evaluate the physical basis for this aerodynamic discrimination. This procedure indicates that differences in size and density confer significantly different inertial properties to the two pollen species. Operating within the specific aerodynamic environments generated around ovules from each species, these differences are sufficient to account for the biases observed in the probability of pollination. Within natural populations, there exists significant variation in pollen size (and possibly in density). Accordingly, it is possible that, under certain ambient wind conditions, ovules from each species can select subsets of the entire airborne population of Ephedra pollen.     

甘肃马先蒿属一新种

本文发表了马先蒿属1新种, 即成县马先蒿Pedicularis chengxianensis Zh.G.Ma et Zh.Zh.Ma sp.nov.。     

山罗花属(玄参科)一新种

描述了一个新种即天柱山罗花,并提供了山罗花属全部已知国产种的分种检索表。     

POLLINATION SYSTEMS OF SYMPATRIC IPOMOEA HEDERACEA AND I. PURPUREA AND THE SIGNIFICANCE OF INTERSPECIFIC POLLEN FLOW

Mathematical models estimated that xenogamy accounted for 7% and 35% of the stigmatic pollen loads of Ipomoea hederacea and I. purpurea, respectively, in experimental populations. The xenogamy estimate for I. hederacea agreed closely with outcrossing estimates previously reported for this species. The discrepancy between the xenogamy estimate and the previously reported outcrossing estimate for I. purpurea could be explained by differing pollinator flight patterns between experimental and natural populations and/or by selection for cross pollen in the pistil of I. purpurea. Interspecific pollen flow from I. purpurea to emasculated flowers of I. hederacea reduced seed production in the latter. The possible significance of interspecific pollen flow from I. purpurea for the evolution of autogamy in I. hederacea was discussed.     

THE POLLINATION ECOLOGY OF ZENOBIA (ERICACEAE)

Zenobia is a shrub endemic to the coastal plain of the Carolinas and southeastern Virginia. The sole species, Zenobia pulverulenta, appears to be weakly self-compatible and partially self-pollinating. Fruit set was reduced, but not eliminated by excluding insect floral visitors. Insect visitors were collected and their pollen loads examined for Zenobia and foreign pollen. Analysis of these pollen loads and observations of insect-foraging behavior indicate that workers of three species of bumblebee (Bombus bimaculatus, B. griseocollis and B. impatiens) are. the principal pollinators of Zenobia. However, pollinator density and composition appear to be strongly influenced by the habitats in which Zenobia grows. Pollen and nectar serve as the primary rewards for pollinators.     

A GENETIC ANALYSIS OF SYMPATRIC SUBPOPULATIONS OF THE SIBLING SPECIES LITTORINA SAXATILIS (OLIVI) AND LITTORINA ARCANA HANNAFORD ELLIS

A detailed analysis of shell characteristics (four parameters)and allozyme allele frequencies (eight to nine polymorphic loci)of sympatric Littorina saxatilis and Littorina arcana subpopulationsfrom Filey Brigg on the east coast of England supports theiridentification as closely related but separate species. Oneenzyme system, esterase-2, was nearly species diagnostic. Resultswere generally comparable with an earlier study of the two speciesfrom East Lothian, Scotland. Littorina saxatilis was again foundto be more variable than L. arcana. (Received 14 December 1983;