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DAVID WEETMAN LORENZ HAUSER PAUL W. SHAW MICHELLE K. BAYES 《Molecular ecology resources》2005,5(2):361-362
Five microsatellite loci are described for the commercially exploited marine gastropod, Buccinum undatum. Levels of polymorphism were variable with three to 19 alleles per locus and expected heterozygosities of 0.26–0.94 in 60 individuals of the population from which the loci were isolated. Homozygote excess at two of the loci might be attributable to null alleles, and these loci should not be used in, for example, parentage analysis. Nevertheless, because null allele frequencies can be estimated and their effects partitioned, all are useful markers for studies of population differentiation. 相似文献
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A whole-plant carbon balance model incorporating a light acclimation response was developed for Alocasia macrorrhiza based on empirical data and the current understanding of light acclimation in this species. The model was used to predict the relative growth rate (RGR) for plants that acclimated to photon flux density (PFD) by changing their leaf type, and for plants that produced only sun or shade leaves regardless of PFD. The predicted RGR was substantially higher for plants with shade leaves than for those with sun leaves at low PFD. However, the predicted RGR was not higher, and in fact was slightly lower, for plants with sun leaves than for those with shade leaves at high PFD. The decreased leaf area ratios (LARs) of the plants with sun leaves counteracted their higher photosynthetic capacities per unit leaf area (Amax). The model was manipulated by changing parameters to examine the sensitivity of RGR to variation in single factors. Overall, RGR was most sensitive to LAR and showed relatively little sensitivity to variation in Amax or maintenance respiration. Similarly, RGR was relatively insensitive to increases in leaf life-span beyond those observed. Respiration affected RGR only at low PFD, whereas Amax was moderately important only at high PFD. 相似文献
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MICHELLE L. GREEN DENISE L. HERZING JOHN D. BALDWIN 《Molecular ecology resources》2007,7(6):1287-1292
Genetic sampling and molecular investigations are important parts of studying wild populations. However, collecting tissues from free‐ranging animals can be difficult or impractical. This study develops a sampling and extraction protocol for template DNA from faecal material collected in a marine environment from small cetaceans. DNA was extracted from faecal material of free‐ranging Atlantic spotted dolphins (Stenella frontalis) and subsequently tested for its suitability in molecular investigations by amplifying both mitochondrial and nuclear DNA. The resulting mitochondrial sequences were found to closely match known S. frontalis haplotypes. Three microsatellite loci were amplified and fall within the expected size range for cetaceans. Mother and calf families previously assigned by observation were genetically confirmed using both mitochondrial haplotype and allele sharing between the mother and offspring. The protocol effectively collects and extracts dolphin DNA from faecal samples and enables species identification as well as confirmation of genetic relatedness and should be considered as a noninvasive alternative to current protocols. 相似文献
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A Sequential Study of Cell Divisions and Expansion Patterns on a Single Developing Shoot Apex of Vinca major 总被引:1,自引:0,他引:1
During the growth of a single developing vegetative apex ofVinca major, both the orientation and frequency of cell divisions,and the pattern of cell expansion, were observed using a non-destructivereplica technique. Micrographs taken at daily intervals illustratethat the central region of the apical dome remains relativelyinactive, except for a phase of cell division which occurs after2 d of growth. The majority of growth takes place at the proximalregions of the dome from which develop the successive pairsof leaves. The developing leaf primordia are initiated by aseries of divisions which occur at the periphery of the centraldome and are oriented parallel to the axis of the subsequentleaves. The cells which develop into the outer leaf surfaceof the new leaves undergo expansion and these cells divide allowingfor the formation of the new leaf. This paper describes thefirst high-resolution sequential study of cell patterns in asingle developing plant apex. Sequential development, cell division, expansion patterns, SEM, Vinca major, apical dome, leaf primordium, leaf initiation 相似文献
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D. CARL FREEMAN MICHELLE L. BROWN MELISSA DOBSON YOLANDA JORDAN ANNE KIZY CHRIS MICALLEF LEANDRIA C. HANCOCK JOHN H. GRAHAM JOHN M. EMLEN 《Biological journal of the Linnean Society. Linnean Society of London》2003,78(1):27-41
Fluctuating asymmetry measures random deviations from bilateral symmetry, and thus estimates developmental instability, the loss of ability by an organism to regulate its development. There have been few rigorous tests of this proposition. Regulation of bilateral symmetry must involve either feedback between the sides or independent regulation toward a symmetric set point. Either kind of regulation should decrease asymmetry over time, but only right–left feedback produces compensatory growth across sides, seen as antipersistent growth following perturbation. Here, we describe the developmental trajectories of perturbed and unperturbed leaves of pumpkin, Cucurbita pepo L., grown at three densities. Covering one side of a leaf with aluminium foil for 24 h perturbed leaf growth. Reduced growth on the perturbed side caused leaves to become more asymmetrical than unperturbed controls. After the treatment the size-corrected asymmetry decreased over time. In addition, rescaled range analysis showed that asymmetry was antipersistent rather than random, i.e. fluctuation in one direction was likely to be followed by fluctuations in the opposite direction. Development involves right–left feedback. This feedback reduced size-corrected asymmetry over time most strongly in the lowest density treatment suggesting that developmental instability results from a lack of resilience rather than resistance. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society , 2003, 78, 27–41. 相似文献
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Energy crops: current status and future prospects 总被引:3,自引:0,他引:3
RALPH E. H. SIMS ASTLEY HASTINGS† BERNHARD SCHLAMADINGER‡ GAIL TAYLOR§ PETE SMITH† 《Global Change Biology》2006,12(11):2054-2076
Energy crops currently contribute a relatively small proportion to the total energy produced from biomass each year, but the proportion is set to grow over the next few decades. This paper reviews the current status of energy crops and their conversion technologies, assesses their potential to contribute to global energy demand and climate mitigation over the next few decades, and examines the future prospects. Previous estimates have suggested a technical potential for energy crops of~400 EJ yr?1 by 2050. In a new analysis based on energy crop areas for each of the IPCC SRES scenarios in 2025 (as projected by the IMAGE 2.2 integrated assessment model), more conservative dry matter and energy yield estimates and an assessment of the impact on non‐CO2 greenhouse gases were used to estimate the realistically achievable potential for energy crops by 2025 to be between 2 and 22 EJ yr?1, which will offset~100–2070 Mt CO2‐eq. yr?1. These results suggest that additional production of energy crops alone is not sufficient to reduce emissions to meet a 550 μmol mol?1 atmospheric CO2 stabilization trajectory, but is sufficient to form an important component in a portfolio of climate mitigation measures, as well as to provide a significant sustainable energy resource to displace fossil fuel resources. Realizing the potential of energy crops will necessitate optimizing the dry matter and energy yield of these crops per area of land through the latest biotechnological routes, with or without the need for genetic modification. In future, the co‐benefits of bioenergy production will need to be optimized and methods will need to be developed to extract and refine high‐value products from the feedstock before it is used for energy production. 相似文献