国外植物学家二三事

哈佛大学植物学教研组织和我国植物分类学的发展有密切关系,最有代表性的单位是格瑞植物标本馆及阿诺树木园,作者在那里学习工作四十年。本文略述其第二学期在傅纳德教授班上,因习俗语言关系,所遭遇的几件趣事。     

Multiple paternity and kinship in the gray fox (Urocyon cinereoargenteus)

Despite mounting evidence that extra-pair copulations (EPCs) are common in the Canidae, no studies have examined the most basal member of this family, the gray fox (Urocyon cinereoargenteus). In this study we explored the possibility that gray foxes may be socially, but not genetically, monogamous. Multiple paternity was confirmed in one litter and suspected in three others (n=7), thus 14.3–57.1% of all litters had more than one father. In this high-density population, multiple paternity may be one strategy to reduce inbreeding, although only one pair was significantly related to each other (r=0.36). Mother–daughter pairs were more common than father–son pairs. These results coupled with a previous study showing a female-biased sex ratio suggest male-biased dispersal and the potential for helper females.     

Multimodal alarm behavior in urban and rural gray squirrels studied by means of observation and a mechanical robot

Urbanization of animal habitats has the potential to affect the natural communication systems of any species able to survive in the changed environment. Urban animals such as squirrels use multiple signal channels to communicate, but it is un-known how urbanization has affected these behaviors. Multimodal communication, involving more than one sensory modality, can be studied by use of biomimetic mechanical animal models that are designed to simulate the multimodal signals and be pre-sented to animal subjects in the field. In this way the responses to the various signal components can be compared and contrasted to determine whether the multimodal signal is made up of redundant or nonredundant components. In this study, we presented wild gray squirrels in relatively urban and relatively rural habitats in Western Massachusetts with a biomimetic squirrel model that produced tail flags and alarm barks in a variety of combinations. We found that the squirrels responded to each unimodal component on its own, the bark and tail flag, but they responded most to the complete multimodal signal, containing both the acoustic and the moving visual components, providing evidence that in this context the signal components are redundant and that their combination elicits multimodal enhancement. We expanded on the results of Parian et al. (2009) by providing data on sig-naling behavior in the presence and absence of conspecifics, suggesting that alarm signaling is more likely if conspecifies are present. We found that the squirrels were more active in the urban habitats and that they responded more to tail flagging in the urban habitats as compared to the rural ones, suggesting the interesting possibility of a multimodal shift from reliance on audio to visual signals in noisier more crowded urban habitats.     

Age-independent,gray matter-localized,brain-enhanced oxidative stress in male fischer 344 rats: brain levels of F(2)-isoprostanes and F(4)-neuroprostanes

While studies showed that aging is accompanied by increased exposure of the brain to oxidative stress, others have not detected any age-correlated differences in levels of markers of oxidative stress. Use of conventional markers of oxidative damage in vivo, which may be formed ex vivo and/or eliminated by endogenous metabolism, may explain these conflicting results. Recently, F₂-isoprostanes and F₄-neuroprostanes, peroxidation products of arachidonic acid and docosahexaenoic acid, respectively, have been identified as sensitive and reliable markers of oxidative injury. Therefore, this study was designed to quantify brain levels of F₂-isoprostanes and F₄-neuroprostanes and their precursors in 4, 10, 50, and 100 week old male Fischer 344 rats. Data show that levels of F₂-isoprostanes and F₄-neuroprostanes were comparable in all animal age groups. However, levels of F₄-neuroprostanes were approximately 20-fold higher than those of F₂-isoprostanes in all age groups, despite the fact that brain levels of docosahexaenoic acid were only twice as high as those of arachidonic acid. Based on our findings, it is concluded that aging is not accompanied by enhanced brain susceptibility to oxidative stress. Furthermore, the metabolically active gray matter of the brain, where docosahexaenoic acid is abundant, appears more susceptible to oxidative stress than the white matter.     

On the tryptic peptides from hemoglobin chains of six carnivores

Summary The amino acid compositions of the tryptic peptides of the following carnivore hemoglobin chains have been determined: gray fox (Urocyon cineroargenteus); raccoon (Procyon lotor); polar bear (Thalarctos maritimus); coati mundi (Nasua nasua) chain; coati mundi (Nasua narica) two chains; cat (Felis catus) chain; and lion (Panthera leo) chain. These provide a basis for future sequencing of these hemoglobins and construction of an evolutionary tree. The specific results are summarized in the following article (Stenzel and Brimhall, 1977).     

Hormonal regulation of aggression toward juveniles in female house mice

Adult female house mice that had been living in groups inflicted more wounds upon juvenile opponents than did females that had been housed in isolation. Ovariectomy blocked this enhancement of aggression by grouping. Aggression in ovariectomized females was augmented by treatment with testosterone propionate, but not by treatment with estradiol benzoate or progesterone. Preputial gland size was greater in group-housed females than in isolates; this difference was abolished by ovariectomy. Testosterone proprionate, but not estradiol benzoate or progesterone stimulated preputial gland growth in ovariectomized mice. These results are interpreted as supporting the hypothesis that the groupinginduced enhancement of juvenile-directed aggression in female mice is mediated by an increased secretion of ovarian androgens.     

中华鲟受精细胞学研究

中华鲟(Acipenser sinensis Gray)的成熟卵具有一层放射膜及二层卵黄膜。在动物极有9—15个受精孔。每一受精孔有一大的入口(12.7—13.9μm直径)及一细长的受精管道(1.2—1.3μm直径)。 进入受精孔的许多精子只能按序入卵。其中只有一个精子的头部膨大核化,最后形成雄性原核。同时活跃的卵子也形成雌性原核。雌、雄原核彼此接触,最后融合成合子核,随后分成两个子核。 中华鲟的受精方式为多精入卵,单精受精。     

ＧＭ（１，Ｎ）模型对生物系统应用的研究

灰色系统理论的GM(1,N)模型已被广泛地用于生态,农业、林业等与生命现象有关的系统的分析和处理。但GM(1,N)本质上是一线性系统,在生态系统中,由于个体和种群的发展均受个体和种群间对有限资源竞争的限制,一般地说线性假设不能成立。本文对GM(1、N)在生态系统的适应性进行了探讨,提出丁系统线性度,系统非线性显著度的概念、定义和具体计算方法,并在此基础上建立了GM(1,N)模型的适用标准。将这一标准施用于计算机模拟的非线性程度不同的生态系统,结果说明本文所提出的系统表征的度量标准基本准确。另外,本文对GM(1,N)中的参数拟合略有改进,新方法在计算上有合理。省时等特点。     

用模糊聚类方法分析灰鼠种群数量年间变化与松籽产量的关系并预报灰鼠种群数量

小哺乳动物年间种群数量波动规律及其食物的影响,是人们早已关注的问题(May,1976;Finerty,1980;Xia Wuping等,1982)。研究这些问题一般使用的数学方法是确定性的非线性常微分方程(nonlinear ordinary differential equation),统计学的自相关分析(autocorrelation analysis)或谱分析(spectral analysis)和快速傅里哀变换(FFT)。