GROWTH OF GONIUM MULTICOCCUM IN SYNTHETIC MEDIA1

Nutrient requirements of Gonium multicoccum (strains 7–1 and 7–2) were investigated in detail. Acetate supported, most efficiently growth in both continuous light and dark. Acetate could be replaced with pyruvate or lactate in the continuous light, but not in the dark. Sugars were completely ineffective. Thiamine was required for optimum growth. The addition of B₁₂ reduced lag phase, but it did not change the final yield. As the sole nitrogen source, nitrate, ammonia, and urea were equally effective. Nitrite, arginine, glutamine, and uric acid, supported scant growth. Examination of the major and minor mineral requirements resulted, in an optimal medium. A growth rate as high as 5.8 doublings per day was obtained at 25 C in continuous light.     

SEXUAL POPULATIONS OF GONIUM PECTORALE (VOLVOCALES)

An investigation of 33 sexual populations of Gonium pectorale has shown sexual isolation not to be as prevalent as previously reported. Only one population was homothallic. Populations from different geographic areas are, in general, sexually compatible. Three groups are discernible based on the degree of intercrossing—the first containing the majority of populations, the second containing only 5 populations, and the third consisting of populations intercrossing with no others. The factors possibly involved in the variable fertility of the populations are discussed. These include the geological history of the collecting areas, migration routes of waterfowl, transport of viable cells by passive means, and cultural conditions (such as pH, temperature, media) used in this investigation.     

论物种的客观真实性

关于物种的概念和本质的争论由来已久。大多数学者认为种是自然界客观存在的真实单位,是形态上和生殖上间断的群体体系,与种内连续的群体体系——宗,有着本质的区别。少数学者则认为种是主观意识的产物,是为了分类的目的而任意确定的人为的分类阶元,与宗只有程度的不同而无本质的区别;只有个体才是客观真实的单位。以形态标准为主的分类学种概念和以生殖隔离为标准的生物学种概念只能说代表了自然界有机体类群不连续性的两个不尽相符,但部分一致的侧面,而不能说就是客观物种的反映。自然界的生命有机体有两重性。它们既不是一群乱七八糟的乌合之众,也不是秩然不紊的鳞次栉比,而是以群体的组织形式适应于各自分布区内的生态位,在表型和基因型的变异式样上具有一定规律的遗传多样性。物种的客观本质也有两重性。物种作为有机体组合的单位既存在又不存在。说物种客观存在是因为按形态或生殖的不连续性标准划分的“种”在自然界具有一定的普遍性;说物种并非客观存在是因为至今还没有一个能把所有的生命有机体都划分成统一的生物学单位的不连续性标准。     

ISOZYME ANALYSIS OF MATING POPULATIONS OF GONIUM PECTORALE (CHLOROPHYTA)1

Intraspecific variation among 36 strains of the freshwater alga Gonium pectorale Müller (Chlorophyceae) isolated from three geographically different locations in Tibet, Nepal, and Japan was investigated by isozyme analysis. Variation in isozyme patterns of eight enzyme systems (malate dehydrogenase, glutamate dehydrogenase, tetrazolium oxidase, lactate dehydrogenase, octanol dehydrogenase, xanthine dehydrogenase, phosphoglucomutase, and malic enzyme) of axenic and clonal cultures was revealed by polyacrylamide gel electrophoresis. Unweighted average linkage clustering, based on Jaccard's similarity coefficient, illustrated the high similarity between most strains from Nepal and all strains from the Ryukyu Islands (Japan). However, there was relatively low similarity between strains from Tibet and those from Nepal and Japan. Strains from the Ryukyu Islands (Japan) grouped into two clusters, and most Nepalese strains formed a single cluster, but Tibetan strains were heterogenous.     

黑粉菌属的聚类分析

本文对我国黑粉菌属(Ustilago)51个样本,选取33个形态学和生物学编码性状进行了类平均法的系统聚类分析。根据聚类分析结果,建议将我国黑粉菌属分为3个表观群(Phenons);茭白黑粉菌目前以放在黑粉菌属内为妥;还认为 Ustilago ocrearum 是 Ustilagokoenigiae 的变种;Ustilago kusanoi 是 Ustilago minima 的变种;Us(?)ilago aoenoe 和 Usti-lago nuda 是两个不同种。     

迎接入侵种的挑战

入侵种是从原来生存的生境中被引入到一个新的生态环境的外来物种,它们勿需面对起源地的天敌和竞争,而且能很快适应新的生境,迅速繁衍,抢夺其他物种的养分和生存空间,造成其他本地物种的减少和灭绝,导致生态失衡,给社会带来经济上的负面冲击,甚至威胁人类的健康.入侵种属于外来种,但入侵种的范围却比外来种的范围小.并不是所有的外来种都会危害生态环境.其侵入过程错综复杂,并且会随着气候环境等因素的变化而变化,因而外来种引进的结果是不可预见的.       

THE DEVELOPMENT OF THE SENSILIUM OF THREE FLEA SPECIES

Abstract The result of a study on the internal structures during the development of sensilium and anal segment from first instar larva to adult of Leptopsylla segnis (Schinherr 1811), Monopsyllus anisus (Rothschild 1907) and Ctenocephalides felis felis (Bouche 1835) is reported and summarized as follows: (1) The development of the sensilium and anal segment of these fleas is essentially the same. (2) The first sensilium rudiment appears in the early third instar larva on the anterior one-second part of the tergite of the tenth abdominal segment, and in prepupa the eleventh abdominal segment which is composed of the dorsal and ventral anal lobes is formed, and in the pupa the sensilium and its frame are fully developed. (3) The differenced of opinions on the terminal segments of the flea are discussed.     

THE CYTOLOGY OF SOME SPECIES OF THE GENUS NOTHOLAENA

Eight taxa in the genus Notholaena were examined for their chromosome numbers; one of the eight had two cytotypes (2 N, 4 N). The other seven consisted of five triploids and two diploids. Observations were also included on spore number and prothallial glandularity whenever possible.     

水玉霉(Pilobolus)属的种的重新划分

我们在过去的工作中承认水玉霉(Pilobolus)属的9个种(郑、胡,见戴,1979)。近年来我们重新分离得到了这些分类群并对它们进行了再研究。研究结果表明,尽管它们是彼此可以互相区分的分类群,但是,包括我们过去的概念在内,目前被普遍接受的用于这个属的分类的种概念太小.为了与整个毛霉目的其它属的分类系统相一致,我们把这9个分类群重新划分为由9个变种组成的5个种:晶澈水玉霉原变种[Pilobolus crystallinu (Wigg.) Tode var. crystallinus],晶澈水玉霉透孢变种新组合[P. crystallinus var.hyalosporus (Boedijn) Hu &Zheng, comb. nov.],晶澈水玉霉克莱因变种新组合[P. crystallinus var.kleinii (van Tieghem) Zheng &G.-q. Chen, comb. nov.],豆状水玉霉原变种(P. lentiger Corda var. lentiger),豆状水玉霉小型变种新组合[P. lentiger var. minutus (Speg.) Zheng &G.-q. Chen, comb. nov.],长型水玉霉(P. longipes van Tieghem),厚壁水玉霉(P. Oedipus Mont.),露水玉霉原变种[P. roridus (Bolt.) Pers. var. roridus],露水玉霉突囊变种新组合[P. roridus var. umbonatus (Butler) Hu &Zheng, comb. nov.]。水玉霉属先后报道过的种或种下分类群名称共计50个左右,其中一些异名往往被不同的作者归到不同的正名下面。为了解决它们的正确归属问题,我们对全部原始描述作了细致的文献考证然后决定其位置。对那些找不到原始描述或从原始描述中得不出结论的则作为可疑名称处理。可疑名称共计12个:Mucor obliquus Scop., M. urceolatus Dicks.;Pilobolus urceolatus Purt., P. pestis-bovinae Hallier(=P. hallierii Rivolta), P. nanus van Tieghem, P. intermedius, (Coem.) P. A. Karsten(=P. Oedipus Mont. var,intermedius Coem.), P. pullus Massee, P.proliferens McVickar, P. ramosus McVickar, P. simplex McVickar, P. lentiger forma leinii Reyn. &Laysa, P. lentiger forma minutus Reyn. &Laysa.     

两种茨藻属植物的染色体组型

笔者曾在1985年报道过分布于我国大陆的6种茨藻属(Najas L.)植物的染色体数目及核型分析结果。而高雄茨藻(N. browniana Rendle)和弯果茨藻(N. ancistrocarpa A. Br. ex Magnus)为笔者不久前(1987年)才发现它们在我国大陆上有分布。据载,仅弯果茨藻前人作过染色体计数工作。因此,作为对整个茨藻属细胞分