THE CHROMOSOMES OF THE SEMPERVIVOIDEAE (CRASSULACEAE)

Uhl , Charles H. (Cornell U., Ithaca, New York.) Chromosomes of the Sempervivoideae (Crassulaceae). Amer. Jour. Bot. 48(2): 114–123. Illus. 1961.—Chromosome numbers are reported for 207 collections representing 68 of the ca. 95 species in this subfamily. Basic numbers are 16, 17, 18, and 19 in Sempervivum, Section Sempervivum (10 species, with many tetraploids and one hexaploid); 19 in Sempervivum, Section Jovisbarba (5 species, all diploid); 15 in Aichryson (9 species, including 1 aneuploid, 1 tetraploid, and 1 aneutetraploid); and strictly 18 in Aeonium (31 species, including 4 wholly and 1 partly tetraploid), Greenovia (3 species, 1 partly tetraploid), and Monanthes (10 species, including 2 wholly and 1 partly tetraploid). The cytological evidence appears decisive in ranking several species of disputed generic position definitely with Aichryson rather than with Aeonium. Possible relationships between various Canarian genera and certain North African species often classed in Sedum are discussed briefly in the light of the scanty morphological and cytological evidence. It is suggested that both these groups may be descended from the same ancestors that were widespread in North Africa before the deserts developed.     

钩翅蛾科亚科的系统演化

过去文献中曾有谑言:如果孟德尔到现代遗传学试验室,他将茫然不知所措;而林奈则仍可坐下做分类学工作。颇有讽刺意味。这是说分类学工作仍沿着林奈的基本方法在做工作,变动不大。这些话过去是如此,现在可不同了。近二、三十年来,分类学大有革新,我在前一篇论文《中国蝙蝠蛾属支序分类》(动物分类学报9(4):397—401)中已经扼要地介绍过一些情况,在此不再重复。     

竹叶马兜铃化学成分的研究(Ⅱ)

<正> 竹叶马兜铃Aristolochia bambusifolia的化学成分,我们在前文曾报导,从其块根分得结晶性单体,已鉴定为D—甘露醇、马兜铃酸,马兜铃酸C、朱砂莲内酰胺,β—谷甾醇外,现本文通过光谱方法,报导其另一个化合物晶V1的鉴定。 晶V1:浅黄色针状结晶,溶于氯仿时呈蓝色荧光,熔点207～208℃。其红外光谱有C=O及CH_3吸收峰1710,1225,1060cm~(-1),无NO_2吸收峰。质谱m/z:340(M~+),     

金丝猴(RHINOPITHECUS)脑的外部形态

本文是对三种金丝猴脑的外部形态的观察结果表明:金丝猴的大脑皮层除存在猴科固有的全部沟裂外,还较其他猴科动物具有更多的副沟。大脑的沟型与疣猴亚科的特征完全吻合,但是很多特点都较叶猴更近似于长臂猿。另外,除了蚓叶和蚓结节较小,四叠体的下丘较猕猴发达以外,金丝猴的小脑和脑干均与猴科的一般特征无明显差异。     

夜蛾科卵的分类(鳞翅目)(一)

本文记述了12种夜蛾的卵。 从不同方向的电镜像片显示出他们的形状和被用作分类的特征,包括精孔区的形态特征,纵脊和横道的状况,气孔的位置、形状和大小,小室的形状和表面结构,以及腹面的细微构造。     

FINE STRUCTURE OF THE NEUROHYPOPHYSIS OF THE OPOSSUM (DIDELPHIS VIRGINIANA)

The neurohypophysis of the opossum (Didelphis virginiana) was studied by electron microscopy in order to amplify Bodian''s classic light microscopic observations in which he demonstrated a definite lobular pattern. The lobule of the opossum neurohypophysis is divided into three regions: a hilar, a palisade, and a septal zone. The hilar portion contains bundles of nerve fibers, the extensions of the hypothalamo-hypophyseal tract containing neurofilaments but few neurosecretory granules. In the opossum, pituicytes have a densely fibrillar cytoplasm. Herring bodies are prominent in the hilar region. They are large bodies packed with neurosecretory granules that have been described as end bulb formations of axons. From the hilar region, axons fan out into a palisade zone where the nerve terminals packed with neurosecretory granules, mitochondria, and microvesicles abut upon basement membranes. The neurosecretory granules are similar to those present in the neurohypophysis of other mammals, except for an occasional huge granule of distinctive type. Material morphologically and histochemically resembling glycogen occurs as scattered particles and as aggregates within nerve fibers. The septal zone, containing collagen, fibroblasts, and numerous small capillaries, is separated from the adjacent glandular tissue by a basement membrane.     

柔嫩艾美耳球虫配子发生的超微结构

利用透射电镜对柔嫩艾美耳球虫配子生殖阶段的超微结构进行了,大配子体和小配子体于相邻的宿主肠上皮细胞内相产生,由末代裂殖子入后,长大变圆而形成,小配子的形成为直接分化型,首先细胞核分裂成为多核体,随后细胞核向周边移动,然后紧靠细胞处的限制向外突出,临近突出部位的限制膜下陷,在核上方形成中心粒,中心粒发育为基粒,鞭毛中的微管和附着微管,早期形成的小配子仍与小配子体的殖体相连,成熟的小配子与配子体分离,外型香蕉状,外被单位膜,内有一电子结构十分致密的细胞核,核的头端侧面有一个巨大的线粒体,小配子有鞭毛2根,每根鞭毛内有微管,组成为9＋2结构,此外,小配子至少有6根附着微管,大配子体和大配子外被单位膜,内部形成大量的成囊体1和成囊体2,并有大量的支链淀粉和脂肪体,中央有一个细胞核,卵囊臂有5层,细胞核位于细胞中央,细胞内有大量的支链淀粉和脂肪体。     

CHROMOSOMES OF THE CHARACEAE OF THE WOODS HOLE (MASSACHUSETTS) REGION

Cytological observations were made on material from 35 collections taken from 21 populations representing 10 species and 2 genera. Haploid chromosome numbers observed in Nitella were 9, 12, 18, 18, 18, and 18 + 36. Those observed in Chara were 14, 28, 28, and 42. Several data indicate that Nitella transilis is an established polyploid of N. tenuissima. The evaluation of chromosome numbers in respect to hybridization, polyploidy, and sexuality in haplobiontic plants is discussed.     

THE FLAVONOIDS OF THE DECIDUOUS RHODODENDRON OF NORTH AMERICA (ERICACEAE)

The native Azaleas of North America (Rhododendron: subgenus Pentanthera) produce 58 flavonoids in five aglycone classes: flavonols, dihydroflavonols, flavanones, dihydrochalcones and chalcones. A comparison of the flavonoids of selected samples of these species indicated that the compounds generally occur as species specific ensembles. Species were grouped into “alliances” based on common flavonoid constituents and a phylogenetic treatment of the group was developed. Evolutionary trends of flavonoids within subgenus Pentanthera are not well-defined but appear to be associated with a loss of the ability to synthesize some compounds and a decrease in diversity of glycosides and methoxylated flavonoids. Intraspecific variation in flavonoids was found in Rhododendron canescens, R. alabamense and R. austrinum when these were sampled on a population basis.     

宝石鱼(Hemichromis bimaculatus)气鳔的听觉机能

在宝石鱼内耳分別记录了切除气鳔前后的微音器电位。以20μV 微音器电位反应为阈值的听力图表明宝石鱼的内耳能接受50—500Hz 的声音信号,最高敏感度在50—200Hz 之间。气鳔完整的宝石鱼,微音器电位幅度与刺激声压强度成比例。气鳔切除后,在50Hz,200—300Hz 之间,声压敏感度下降5—6dB,表明宝石鱼的气鳔有辅助的听觉作用。