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61.
DNA barcoding is a tool to provide rapid and accurate taxonomic identification using a standard DNA region. A two-marker combination of rnatK+rbcL was formally proposed as the core barcode for land plants by the Consortium for the Barcode of Life Plant Working Group. However, there are currently no barcoding primers for matK showing high universality in gymnosperms. We used 57 gymnosperm species representing 40 genera, 11families and four subclasses to evaluate the universality of nine candidate matK primers and one rbcL primer in this study. Primer (1F/724R) of rbcL is proposed here as a universal primer for gymnosperms due to high universality. One of the nine candidate matK primers (Gym_F1A/Gym_R1A) is proposed as the best "universal" matK primer for gynnosperms because of high polymerase chain reaction success and routine generation of high quality bidirectional sequences. A specific matK primer for Ephedra was newly designed in this study, which performed well on the sampled species. The primers proposed here for rbcL and matK can be easily and successfully amplified for most gymnosperms. 相似文献
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Abstract.
- 1 Nectivore foraging environments are typically modelled as choices among non-fluctuating rewards, but in reality they often consist of intermittent daily nectar and pollen sources. Intermittent rewards create two distinct foraging problems for colonial nectivores: re-recruitment (periodically returning to intermittent rewards) and re-allocation (finding new rewards).
- 2 The role of scent in learning and remembering the locations of discontinuous nectar rewards was examined by testing re-recruitment efficiency of Apis cerana and A.dorsata to reward-correlated scents (odour discriminant self-conditioning). Experiments examined the responses of non-naive foragers to an odour correlated with prior reward, and to odours not correlated with prior rewards, by placing different scents into a colony and observing the number of bees re-recruited to a feeding station.
- 3 Re-recruitment of non-naive foragers in both species was significantly greater in response to the conditioning scent than to the experimental controls. However, species behaviour differed in one aspect; re-recruited A.cerana foragers landed on the feeding station when unscented reward was offered, whereas re-recruited A.dorsata foragers returned but would not land without conditioning scent present in the reward.
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Foliar application of gibberellic acid greatly enhanced theformation of secondary capitula. The proportion of primary capitulashowing this feature increased from 6% in the controls to 28,58, and 54% at 100, 250, and 500 parts 106 GA3, respectively.Secondary capitula were initiated either along the peripheryor in the centre of the receptacle or from both; their totalnumbers for 15 plants per treatment were 53, 215, 660, and 404in response to 0, 100, 250, and 500 parts 106 GA3, respectively.Secondary capitula were smaller and had fewer disc florets andfruits, particularly of the wingless and smalltype. Tertiary capitula, not observed in nature, formed on 2.72and 3.21% of the secondary capitula on plants sprayed with 250and 500 parts 106 GA3.The formation of a secondary inflorescencemeristem in treated plants in place of a floret primordium canbe detected histologically early in its development, and itspattern of development resembles that of the primary capitulum. 相似文献
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LAURÉNE GAY PAUL E. EADY RAM VASUDEV DAVID J. HOSKEN TOM TREGENZA 《Physiological Entomology》2009,34(1):86-92
Abstract The optimal number of mating partners for females rarely coincides with that for males, leading to sexual conflict over mating frequency. In the bruchid beetle Callosobruchus maculatus, the fitness consequences to females of engaging in multiple copulations are complex, with studies demonstrating both costs and benefits to multiple mating. However, females kept continuously with males have a lower lifetime egg production compared with females mated only once and then isolated from males. This reduction in fitness may be a result of damage caused by male genitalia, which bear spines that puncture the female’s reproductive tract, and/or toxic elements in the ejaculate. However, male harassment rather than costs of matings themselves could also explain the results. In the present study, the fitness costs of male harassment for female C. maculatus are estimated. The natural refractory period of females immediately after their first mating is used to separate the cost of harassment from the cost of mating. Male harassment results in females laying fewer eggs and this results in a tendency to produce fewer offspring. The results are discussed in the context of mate choice and sexual selection. 相似文献
65.
SETH G. PRITCHARD ALLAN E. STRAND M. LUKE McCORMACK MICHEAL A. DAVIS† ADRIEN C. FINZI‡ ROBERT B. JACKSON§ ROSER MATAMALA¶ HUGO H. ROGERS RAM OREN§ 《Global Change Biology》2008,14(3):588-602
Efforts to characterize carbon (C) cycling among atmosphere, forest canopy, and soil C pools are hindered by poorly quantified fine root dynamics. We characterized the influence of free‐air‐CO2‐enrichment (ambient +200 ppm) on fine roots for a period of 6 years (Autumn 1998 through Autumn 2004) in an 18‐year‐old loblolly pine (Pinus taeda) plantation near Durham, NC, USA using minirhizotrons. Root production and mortality were synchronous processes that peaked most years during spring and early summer. Seasonality of fine root production and mortality was not influenced by atmospheric CO2 availability. Averaged over all 6 years of the study, CO2 enrichment increased average fine root standing crop (+23%), annual root length production (+25%), and annual root length mortality (+36%). Larger increase in mortality compared with production with CO2 enrichment is explained by shorter average fine root lifespans in elevated plots (500 days) compared with controls (574 days). The effects of CO2‐enrichment on fine root proliferation tended to shift from shallow (0–15 cm) to deeper soil depths (15–30) with increasing duration of the study. Diameters of fine roots were initially increased by CO2‐enrichment but this effect diminished over time. Averaged over 6 years, annual fine root NPP was estimated to be 163 g dw m?2 yr?1 in CO2‐enriched plots and 130 g dw m?2 yr?1 in control plots (P= 0.13) corresponding to an average annual additional input of fine root biomass to soil of 33 g m?2 yr?1 in CO2‐enriched plots. A lack of consistent CO2× year effects suggest that the positive effects of CO2 enrichment on fine root growth persisted 6 years following minirhizotron tube installation (8 years following initiation of the CO2 fumigation). Although CO2‐enrichment contributed to extra flow of C into soil in this experiment, the magnitude of the effect was small suggesting only modest potential for fine root processes to directly contribute to soil C storage in south‐eastern pine forests. 相似文献
66.
MIREN ARANTZAZU ELEJALDE Ma JOSÉ MADEIRA BENITO MUÑOZ JOSE RAMÓN ARRÉBOLA BENJAMÍN J. GÓMEZ‐MOLINER 《Zoological Journal of the Linnean Society》2008,154(4):722-737
Iberus gualtieranus is a species complex of land snails that is endemic to the Iberian Peninsula. The species taxonomy of the group is based merely on the basis of shell morphology, but validity of the existing taxonomy is uncertain. Using mitochondrial DNA (mtDNA) data (cytochrome oxidase I and 16S rRNA sequences) we were able to validate the observed phylogenetic taxa within the I. gualtieranus s.l. complex by means of the analysis of specimens of the different morphospecies, together with the study of topotypes. Strong incongruences were obtained between morphology and molecular data. The Iberus alonensis morphospecies comprised several genetically divergent but morphologically cryptic lineages. Considering (1) the allopatric distribution of the operational taxonomic units (OTUs), (2) the morphological differentiation, (3) the possible occurrence of hybridization among the different lineages, and (4) the strong differentiation of the mtDNA phylogroups, we suggest the main lineages obtained, for the time being, may be treated as evolutionary species. The robust phylogenetic reconstruction obtained allows us to consider I. alonensis s.s., Iberus campesinus, Iberus carthaginiensis, and Iberus gualtieranus s.s. as valid species. Two additional unnominated taxa of the alonensis shell type have also been identified. Further subdivisions are also considered, including Iberus gualtieranus mariae and Iberus gualtieranus ornatissimus. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 722–737. 相似文献
67.
RAJESH TANDON K. R. SHIVANNA H. Y. MOHAN RAM 《Botanical journal of the Linnean Society. Linnean Society of London》2001,135(3):251-262
Phenology, pollination biology and breeding system were investigated in three populations of Acacia senegal located in Delhi and Rajasthan. Flowers emit a mild fragrance and produce a minute quantity of nectar. The stigma is wet non-papillate, cup-shaped and generally accommodates one polyad with 16 pollen grains. The style is solid. The mass effect created by the brush type of blossoms attracts a wide variety of insects, of which the giant Asian honeybee, Apis dorsata , is the effective pollinator. Manual in vivo pollination studies have shown that the species is self-incompatible. Self-incompatibility appears to operate inside the embryo sac. Under natural conditions fruit set is as low as 0.36%. Insufficient pollination is the main cause of low fruit set. Manual xenogamous pollinations substantially improve fruit set to 30% 相似文献
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