铅锌矿尾矿场植被重建的生态学研究Ⅰ.尾矿对种子萌发的影响

在实验条件下,供试的林木、农作物及牧草种子均能在铅锌矿尾矿中萌发,其中萌发率与非污染土壤中的相近,多数种子的萌发速率低于对照组。供试植物幼苗出土30天内没有死苗现象,但与对照相比,株高下降28.4%,复叶数减少34.1%,生物量下降52.6%.     

Vegetation survey of the Wasgomuwa National Park,Sri Lanka: analysis of the Wasgomuwa Oya Forest

Three types of forests were recognised (high, disturbed and open) based on the openings in the canopy in a Tropical Monsoonal Forest at the Wasgomuwa National Park, Sri Lanka. The analysis of these forests showed that the species composition varied between forest types. The shrub vegetation, not only was very characteristic but was also a major component in each forest, unlike in the tropical rain forest. The exact role of the shrubs in the dynamics of the tropical monsoon forests is not established, but is suggested that it may act as a buffer during the dry periods under a semi deciduous canopy. The sapling composition differed from the tree vegetation and indicated that the species composition may change with time in this forest. Mosaic theory or the patch dynamics may best explain the dynamics of this tropical monsoon forest which is a mixture of forest types. More studies are required before generalisations can be made of tropical monsoon forests.     

用原位分子杂交技术定位牛生长激素基因于5号染色体

本工作利用放射性标记的ｂＧＨ基因（３．０ｋｂ）为探针,通过原位杂交定位牛生长激素基因于染色体５ｑ２２－２６内。该结果与以前的ｂＧＨ基因定位的结果不同,讨论了基因探针、基因定位方法等方面与定位准确性的关系。     

方程dx/dt=f(x(t-1))具有多个周期的周期解并蕴含浑沌的条件

本文给出了方程dx/dt=f(x(t-1))出现4/(2n 1),4/(2n-1),4/(2n-3),…,4/7,4/5,4/3,4一周期解并蕴含浑沌的一个条件。     

铅锌矿尾矿场植被重建的生态学研究：Ⅰ.尾矿对种子萌发的影响

在实验条件下,供试的林木、农作物及牧草种子均能在铅锌矿尾矿中萌发,其中萌发率与非污染土壤中的相近,多数种子的萌发速率低于对照组．供试植物幼苗出土３０天内没有死苗现象,但与对照相比,株高下降２８．４％,复叶数减少３４．１％,生物量下降５２．６％．     

伪狂犬病毒闽A株基因文库的构建及物理图谱分析

本文报道以质粒ｐＢＲ３２２作载体,用鸟枪法克隆出了ＰＲＶ闽Ａ株除ＢａｍＨＩ－１,２外的所有酶切片段,构建了ＰＲＶ闽Ａ株基因文库,并以克隆出的ＢａｍＨＩ片段用光生物素标记作探针,应用分子杂交法确定了ＰＲＶ闽Ａ株绝大部分限制性内切酶位点的位置。     

满族新生儿血红蛋白F中G_γ／A_γ比值测定及其异常者γ－珠蛋白基因图谱分析

以聚丙烯酰胺凝胶电泳方法测定了３３１例辽宁满族新生儿脐带血血红蛋白Ｆ中Ｇγ／Ａγ比值。结果显示：高Ｇγ（＞８０％）者４例,占１．２１％,其基因频率（ｆ）为０．００６０４,低Ｇγ（３０－４８％）者６例,占１．８１％,其基因频率为０．００９０６,其余正常,Ｇγ平均值为６５．２３±６．３８％。未发现ＡγＴ链。对其中八例异常者（４例高Ｇγ值,４例低Ｇγ值）的染色体ＤＮＡ进行了基因图谱分析,确定４例高Ｇγ值者基因型有两种：Ｇγ－Ｇγ／Ｇγ－Ａγ二例,Ｇγ－ＡＧγ－Ａγ／Ｇγ－Ａγ二例;４例低Ｇγ值者基因型有二种,分别为：Ａγ－Ａγ／Ｇγ－Ａγ二例和－ＧＡγ／Ｇγ－Ａγ二例。其中Ａγ－Ａγ基因型在中国人群中未见报道过。     

Molecular markers applied to plant tissue culture

Summary The last decade has witnessed successful applications of plant tissue culture techniques in several crops. During that same period, studies in plant molecular genetics have also grown exponentially. Molecular markers (isozymes, RFLPs, and PCR-based markers such as RAPDs) are now used to study many of the current limitations of tissue culture. They have been used to investigate mechanisms that underlie somaclonal variation in the nuclear, mitochondrial, and chloroplast genomes. One recurrent problem with several tissue culture systems has been the difficulty of determining the origin of regenerants. Molecular markers represent powerful tools to determine precisely the origin of plants derived from microspore or anther culture, protoplast fusion, and other tissue culture studies where this information is important. With improvements in tissue culture techniques, populations of doubled haploid lines have been produced in several major crop species. Doubled haploid populations have proven useful in the production of molecular maps and in tagging important agronomic traits. This review describes the use of molecular markers to address fundamental and practical questions of plant tissue culture, and discusses the potential of improvements in molecular techniques and new molecular markers such as SCAR and STS along with high-resolution mapping strategies.     

Fire and competition in Australian heath: a conceptual model and field investigations

Abstract. We describe a model of heath vegetation, in which species were classified into five functional groups based on characteristics of their propagule pools, post-fire growth, timing and mode of reproduction and competitive status. The model assumes no recruitment without fire and a simple competitive hierarchy based on vertical stature. A critical feature of the model is an initial post-fire window of 5–6 yr in which competition from overstorey species on understorey species is reduced. Understorey functional groups differ in their ability to exploit this window. In the field, we tested five predictions derived from the model: (a) overall species richness of understorey varies inversely with overstorey density as a result of a trend in richness of woody species, but not in herbaceous species; (b) where an overstorey was present in the previous fire interval, post-fire population density is reduced in a functional group of understorey serotinous resprouting shrubs, but not in a group of understorey obligate-seeding shrubs with soil seed banks; (c) in understorey serotinous resprouting shrubs, post-fire regrowth in resprouting individuals is adversely affected by the presence of an overstorey in the preceding fire interval; (d) in understorey serotinous resprouting shrubs, levels of pre-fire propagules are lower in the presence of an overstorey, reducing the density of post-fire recruits; and (e) in understorey serotinous resprouting shrubs, recruitment relative to the pre-fire population is unaffected by overstorey species within the window of reduced competition. Of these, three tests (a,b,d) supported the model, one (e) may support the model, but the results were inconclusive and one (c) did not support the model. Limitations and further applications of the model are discussed. Our results suggest that maintenance of high densities of overstorey populations is in conflict with conservation of some understorey species. Models of the type we propose will help identify and resolve such conflicts and promote the judicious use of fire to maintain full species diversity of plant communities.