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数学在生物学的应用中,生态学是历史最久远和成果最丰富的领域。通过AlfredLotka和VitoVolterra的努力,考虑种群相互作用的动力学因素的框架几乎在一个世纪之前就被引进来。随后受他们那些创新工作的鼓舞和启发,引出数千篇论文。然而,虽然已成名的数学家Volterra是被数据资料亚得里雅海的渔场产量的波动所激励而导致数学上的创新,可是后来出现的相当多的文章却完全跟数据资料脱节,在数学上只是些乏味的推演。在Volterra的研究出现后的半个世纪中,生态学失去了活力,很难指出在那一段时间里有…  相似文献   

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苍术(Atractylodeslancea(Thunb.)DC.)种内遗传多样性分析   总被引:6,自引:0,他引:6  
分析了苍术5种等位酶12个倍点25个等位基因的分化特征。结果表明:群体内多态位点比例平均为0.61,每们位点的平均杂合率为0.26,每个位点发现的平均等位基因数为1.78。  相似文献   

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在野外居群调查的启示下,本文以组件观点对柳叶野豌豆复合种和歪头菜幼苗亚单位的时序变化与开花关系进行了分析。结果发现在柳叶野豌豆复合种栽培居群中存在打破物种间形体结构特征的个体,即在复叶由一对小叶组成折植株就已开花而进入生殖时期。另外,在歪头菜的野生居群中发现由三或四枚小叶组成复叶的个体,因此,我们推测这种形体结构的变化可能暗示着柳叶野豌豆复合种和歪头菜有着共同的祖先。  相似文献   

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Riassunto Lo studio comprende una revisione critico-sperimentale della specie Actinomyces albus, della quale vengono considerati come sinonimi circa 30 nomi speeifici, fra i quale A. chromogenus, A. odorifer, A. thermophylus p.p.; della specie é data una diagnosi ed una particolareggiata descrizione.Sono inoltre studiate le specie A. viridis, (= A. viridochromogenus) e A. innominatus, n. nomen. Quest'ultima é preceduta da una breve discussione sulla specie A. homini.
Summary Twenty-six strains of Actinomyces albus are studied redescribed from morphological, cultural and biochemical standpoints. Many biological activities of A. chromogenus, A. odorifer and A. thermophilus are in common with other species of the same genus, so that they may be considered for sub-specific, (not specific) differentiation. A discussion on A. farcinicus, A. albidoflavus and A. aureus has been originated from mislabeling as A. albus; the group including the two last named species (flavus group) must be revised. A few strains classified A. farcinicus are in no doubt true A. albus, but this real specific entity remains to be revised from Nocard's strain. A. viridis, for the first time described by Lombardo-Pellegrino, has been redescribed three times as a new species under the same binomial, and the fourth as A. viridochromogenes. A. hominis Bostroem is an uncorrect determination for the species originally described by Waksmann and Curtiss, and it is renamed A. innominatus, the binomial A. (Streptothrix) hominis Auct. being a nomen ambiguum. In conclusion, 30 bionmial are appended in sinonimy to A. albus, including Cladothrix dichotoma Macé (1888) non Cohn, G. invulnerabilis Acosta et G. Rossi, C. odorifera Rullm. Actinomyces chromogenus Gasp., A. thermophilus Auct., p.p., A. (Streptothrix) Sanninii (Cif.) Westerd., A. Almquisti Duché, A. Gougeroti Duché, and so on.
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A collection of genetic lines in 8 reproductively isolated Pichia species has been created. The above data have permitted realizing intraspecific hybridization and showing normal meiotic segregation of auxotrophic markers.  相似文献   

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Chromosome number determinations from 118 populations of eight species of the aster genus Virgulus are reported for the first time. Based on these counts and literature reports the geographic distributions of diploids and tetraploids in V. concolor, V. novae-angliae, V. oblongifolius, and V. patens have been determined. In the first three species, diploids were widely distributed, while tetraploids were more restricted. In V. patens, diploids were restricted to the southwestern portion of the species’ range, while tetraploids were found throughout the range. Both V. adnatus and V. walteri were found only at the tetraploid level throughout their ranges. Two other species with restricted distributions were consistently found to be high level polyploids: V. georgianus with 2n = 50, V. grandiflorus with 2n = 60. The following new combinations are listed: Virgulus georgianus (Alexander ex Small) Semple; Virgulus subsect. Brachyphylli (Torr. & Gray) Semple; and Virgulus sect. Polyliguli (Semple & Brouillet) Semple.  相似文献   

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