黑斑蛙蛰眠前后形态生理生态变化初探

本文回归分析,表明黑斑蛙（Ｒａｎａ ｎｉｇｒｏｍａｃｕｌａｔａ）出蛰、入蛰时体长与体重、胴体重和体重与肝重、脂肪体重、生殖原重之间均存在非常显著的线性相关关系;通过对一些生理常数的显著性检验,右知蛰眠后的肥满度、脂肪体系数、肝系数显著减小,生殖腺系数啬非常显著,躯体肥满度无明显变化。     

THE EVOLUTION AND COMPARATIVE PHYSIOLOGY OF TERRESTRIAL AND FRESHWATER NEMERTEANS

(1) Parallel evolution from separate marine ancestors has given rise to two groups of genera of terrestrial nemerteans, representative of at least two different family stocks. They have colonized land by the direct route, moving up the shore on widely separated oceanic islands. The relationships between the known terrestrial and semi-terrestrial nemerteans, comprising seven genera and 15 species, are defined and their geographic distribution is discussed.
(2) In fresh water, three heteronemertean and nine hoplonemertean species are known. The hoplonemerteans arise from two different families representing two different evolutionary routes to fresh water, one by way of estuaries and the other via land. The distribution of freshwater nemerteans and the characters common to all species are discussed.
(3) Very little is known about the comparative physiology of land and freshwater nemerteans. However, information about the physiology of marine forms is combined with morphological differences from them found in terrestrial and freshwater species to suggest profitable lines of future research.
(4) Water relations pose a major problem for both terrestrial and freshwater nemerteans. The role of the cerebral organs, the blood and the excretory system in the osmotic physiology of some littoral nemerteans is beginning to be understood. These systems in land and freshwater forms have clearly distinctive features which need to be thoroughly investigated.
(5) Suggestions are given for valuable lines of investigation of the mucous glands, digestive physiology and general behaviour of terrestrial and freshwater nemerteans.     

油菜菌核病菌生理生态研究

通过试验分析,结果得出,油菜菌核病菌生长温度范围在0～34℃之间,23℃以下菌丝生长速度与温度呈正相关,25℃以上则呈负相关,23～25℃最适宜,菌丝和菌核致死温度分别为45℃和75℃．该菌对酸碱度适应范围很广,PH1～14范围内只在PH_1条件下不能生长,其最适PH值为5～6。病菌利用铵态氮源能力最强,硝态氮源次之,不能利用亚硝态氮;对氨基酸利用能力以精氨酸最强,其次是酪氨酸、天门冬氨酸和谷氨酸,赖氨酸最差。植株内精氨酸和赖氨酸比值大的白菜型油菜“黄鳝籽”病情扩展最快。     

淡水鱼类种质资源生态库的研究现状与展望

水生生物种质资源是水产增养殖业发展的重要物质基础。发达国家都十分重视水生种质资源的研究。我国自80年代以来开始淡水鱼类种质资源的研究,先后在长江水系进行了淡水鱼类种质资源天然生态库、人工生态库(含冷冻库)建设,同时进行了不同流域间淡水鱼类的考种,淡水鱼类种质鉴定技术、标准参数及种质标准研究,取得了较好的进展。       

PARASITIC CRUSTACEANS OF AFRICAN FRESHWATER FISHES FROM THE NILE AND NIGER SYSTEMS

New crustaceans parasitie on African freshwater fishes of the Nile, or former Nile, and Niger systems are described. The taxonomy of a group of closely related species of Argulus is clarified, and errors in the older literature are corrected. Additional information on distribution is presented.     

GLOCHIDIA OF THE FRESHWATER MUSSEL LAMPSILIS OVERWINTERING ON FISH HOSTS

Largemouth Bass were infected with glochidia of the freshwatermussel Lampsilis cardium. Three fishes each were held at 4.5,10, and 15.5°C; five fish were held at 21°C. By 64 days,metamorphosed juveniles were found in the 15.5 and 21°Ctrials but not in the 5.5 and 10°C trials, indicating thatthe lower threshold temperature for metamorphosis was between10 and 15.5°C for the duration. In a second experiment,Largemouth Bass were infected with glochidia of L. cardium andheld at 10°C. A sample of fishes was removed monthly andbrought to 21°C. Numbers of glochidia that metamorphosedafter being warmed were compared to the number that metamorphosedwithout warming. The percentage that metamorphosed after warmingdecreased linearly with time. At one month, 100% of the glochidiametamorphosed after warming. This decreased to 80% by two months,to 30% by four months and 3% by six months. Although this post-warmingpercentage decreased with time, the total percentage of metamorphosedjuveniles (at all temperatures) was not correlated with time.Controls kept at 21°C required three weeks to reach peakmetamorphosis, but test subjects subjected to 10°C requiredless than nine days to metamorphose once warmed. Many overwinteringglochidia therefore complete a portion of their developmenton the host at winter temperatures, but stop short of excystment.Some glochidia metamorphosed without being warmed, but thisphenomenon is not understood. This study confirms that glochidiamay overwinter on hosts, with some glochidia persisting formore than six months before metamorphosing when warmer conditionsreturn. (Received 29 September 1998; accepted 18 January 1999)     

亚洲淡水和陆生龟鳖类12S rRNA基因片段的序列分析和系统发生研究

对亚洲产淡水和陆生龟鳖４科２３个种进行了ＤＮＡ序列水平的分子系统学研究，用ＰＣＲ技术扩增约４００ｂｐ的线粒体１２ＳｒＲＮＡ基因片段进行了序列分析，合并从ＧｅｎＢａｎｋ中检索到的其它龟鳖类的序列数据，在基于二级结构的对位排列基因上用邻结法地系统发生研究。结果表明，潮龟科与陆龟简拼要缘关系比龟科与陆龟科的近；支持将平胸龟属归为鳄龟上属；潮产是并系起源，从１２ＳｒＲＮＡ基因序列得到的系统发生关系不支持根