STRUCTURE OF THE VASCULAR PARENCHYMA IN THE STEM OF LYCOPODIUM LUCIDULUM

At maturity the vascular cylinder of the stem of Lycopodium lucidulum contains two distinct types of parenchyma cells, one which is always associated with sieve cells, the other with tracheids. The remaining parenchyma cells have characteristics intermediate between the two extremes. The most conspicuous feature of the sieve cell-associated parenchyma cell is the very dense appearance of its protoplast, due to a high ribosome population and absence of large vacuoles. The large, ramifying nuclei of these cells have numerous connections with the endoplasmic reticulum (ER). The tracheid-associated parenchyma cells, which are light in appearance, contain many small vacuoles and a relatively small ribosome population. These cells also contain relatively small nuclei and considerable ER cisternae. The parenchymatous elements which have characteristics intermediate between sieve cell- and tracheid-associated parenchyma may or may not be contiguous to the sieve cells or tracheids. An intergradation in wall thickness occurs among parenchyma cells of the vascular cylinder, the thicker-walled cells being adjacent to the sieve cells, the thinner-walled ones next to the tracheids. An intergradation also occurs in the frequency of plasmodesmata between the various parenchyma cells. The closer parenchyma cells are to the sieve cells the greater the number of connections between them. No plasmodesmata were found between the tracheid-associated parenchyma cells.     

FINE STRUCTURE OF CHLORIDE CELLS FROM THREE SPECIES OF FUNDULUS

A morphological basis for osmoregulation in the teleosts was studied by comparing the fine structure of chloride cells found in epithelia of the gills of three species of fish: Fundulus heteroclitus which can survive in a wide range of salinities, and F. similis and F. chrysotus which are usually restricted to salt water and fresh water environments, respectively. Gills were removed from F. heteroclitus which had been laboratory adapted to either sea water or pond water. For a comparison, gills were also removed from the marine F. similis and the fresh water F. chrysotus which had been adapted to their natural environments. Gill-filaments were fixed in Millonig's phosphate buffered (pH 7.4), 1 per cent osmium tetroxide and were embedded in Epon. Thin sections of filaments were stained with lead hydroxide. The cytoplasm of chloride cells of all three species of Fundulus is heavily populated with mitochondria and is filled with tubules of the agranular endoplasmic reticulum (ER). An orderly secretory cycle was indicated for chloride cells of salt water adapted F. heteroclitus and the marine F. similis. An amorphous material is observed in the agranular ER. Its density increases towards the apical end of the cell. In the apical cytoplasm, tubules of the agranular ER appear to converge and to discharge the amorphous material into an apical cavity. Except for the actual opening of the apical cavity, the distal end of salt water adapted chloride cells is characteristically shielded from the hypertonic environment by thin cytoplasmic flanges projecting from the neighboring epithelial cells. Chloride cells of the fresh water F. chrysotus resemble chloride cells of pond water adapted F. heteroclitus, in that these cells do not have apical cavities with the functional appearance of those in the sea water adapted forms. The distal end of fresh water adapted chloride cells is typically exposed to the free surface of the gill-filament. The possible function of the cell type is discussed.     

石首鱼科(Sciaenidae)三种鱼耳石CaCO_3晶相结构分析

软骨及硬骨鱼以及其它高等脊椎动物耳石中,CaCO_3占绝大部分.本文主要以X射线衍射分析对白姑鱼,大黄鱼,小黄鱼三种石首鱼科鱼类耳石作了分析,发现CaCO_3结晶均为霰石结构.依文献,对耳石晶相结构在动物分类上的意义作了初步讨论.     

SPERMOGENESIS AND SPERM STRUCTURE IN THREE SPECIES OF PATELLOIDA AND ONE SPECIES OF NIPPONACMAEA (PATELLOGASTROPODA: ACMAEOIDEA)

The spermatozoa of Patelloida profunda albonotata, P. saccharina,P. pygmaea and Nipponacmaea schrenkii (Lottiidae) are describedby transmission electron microscopy. All have ect-aquasperm,typical of invertebrates using external fertilization. The spermof all four species have a cylindrical nucleus (length: breadth> 4: 1 in P. p. albonotata and P. saccharina; <4: 1 inP. pygmaea and N. schrenkii) which tapers towards the roundedanterior end. All have an acrosome with a posterior acrosomallobe which extends into the centre of the subacrosomal space.In P. p. albonotata and P. saccharina the acrosomal contentsare undifferentiated and the posterior lobe extends to the nucleus,being separated from it by flocculent material. In P. pygmaeathe acrosomal contents are differentiated, the lobe is relativelyshort and the subacrosomal space is filled with material witha fibrous appearance. The acrosome of N. schrenkii is undifferentiatedand the posterior lobe is no more than a bulge. The sperm ofP. p. albonotata and N. sacchrina have a small (0.25 µmlong) cytoplasmic collar which surrounds the axoneme anteriorlywhereas in P. pygmaea and N. schrenkii the cytoplasmic collaris longer (1 µm) and is swollen by an electron-dense vesicle.The composition and function of this vesicle is unknown. Thespermatozoa of Patelloida and Nipponacmaea have structural featureswhich are similar to sperm of the Lottiidae providing some supportfor the placement of these genera in the Lottiidae as proposedby Lindberg & Hedegaard (1996) and Sasaki & Okutani(1993) respectively. The similarities of the sperm of P. pygmaeato N.schrenkii raise some doubts about the tax-onomic statusof the former species. Spermiogenesis in all four species issimilar to that described for other Acmaeoidea and Patelloidea.In P. pygmaea and N. schrenkii, however, in addition to theacrosomal vesicle, the Golgi body produces a number of electron-densevesicles which fuse and eventually form a single vesicle inthe collar of the mid-piece. (Received 24 October 1996; accepted 10 February 1997)     

STRUCTURE AND DEVELOPMENT OF THE SIEVE ELEMENT IN THE STEM OF LYCOPODIUM LUCIDULUM

Stem tissue of Lycopodium lucidulum Michx. was fixed in glutaraldehyde and postfixed in osmium tetroxide for electron microscopy. Although their protoplasts contain similar components, immature sieve elements can be distinguished from parenchymatous elements of the phloem at an early stage by their thick walls and correspondingly high population of dictyosomes and dictyosome vesicles. Late in maturation the sieve-element walls undergo a reduction in thickness, apparently due to an “erosion” or hydrolysis of wall material. At maturity, the plasmalemma-lined sieve elements contain plastids with a system of much convoluted inner membranes, mitochondria, and remnants of nuclei. Although the endoplasmic reticulum (ER) in most mature sieve elements was vesiculate, in the better preserved ones the ER formed a tubular network closely appressed to the plasmalemma. The sieve elements lack refractive spherules and P-protein. The protoplasts of contiguous sieve elements are connected with one another by pores of variable diameter, aggregated in sieve areas. As there is no consistent difference between pore size in end and lateral walls these elements are considered as sieve cells.     

三种烟草属植物的核型分析

本文对三种烟草属植物进行了核型分析。粘烟草Ｎｉｃｏｔｉａｎａｇｌｕｔｉｎｏｓａ为二倍体,其核型可简式为：２ｎ＝２４＝１０Ｍ＋１０ｍ＋４ｓｍ（２ＳＡＴ）;内索菲拉烟草Ｎ．ｎｅｓｏｐｈｉｌａ和斯托克通氏烟草Ｎ．ｓｔｏｃｋｔｏｎｉ可能均为双二倍体,其核型简式,前者为２ｎ＝４８＝６Ｍ＋２０ｍ（２ＳＡＴ）＋１８ｓｍ＋４ｓｔ,后者为２ｎ＝４８＝１４Ｍ＋１２ｍ＋１８ｓｍ＋４ｓｔ。此外,作者对供试材料的染色体基数、倍性及随体等问题进行了初步讨论。     

OBSERVATIONAL LEARNING IN THREE SPECIES OF BIRDS

White-throated Sparrows Zonotrickia albicollis, Fork-tailed Flycatchers Muscivora tyrannus and Black-capped Chickadees Porta atricapillus were placed in experimental situations where they could watch a trained companion uncover a hidden mealworm. After a period of watching its companion find the concealed mealworm, the observer bird was isolated visually from the other bird. While in isolation the observer birds approached, touched and pecked at a hidden food tray significantly more often than control birds which had not had an opportunity to observe a trained companion. However, the experimental birds failed to learn from observation alone how to uncover the concealed mealworm. But if rewarded in the presence of the companion bird (by taking a mealworm from it or by uncovering a mealworm as a result of local enhancement), then the observer bird frequently did come to find the prey in isolation. It is suggested that the interaction between observational learning and a bird's reinforced socially facilitated experience could assist in the development and expansion of a bird's behavioural repertoire.     

A COMPARATIVE STUDY OF THE FOLIAR ANATOMY OF LYCOPODIUM SPECIES

A comparative study of the leaves of 31 species of Lycopodium was made. The pattern of tracheids varies with the species. Usually they exhibit annular, helical, reticulate, modified or transition forms; none of the species have advanced phylogenetically beyond the scalariform tracheid stage. Mucilage canals have been found in four species. Tracheids are enclosed by a few to several layers of oblique ended, elongated parenchyma cells in most species, but an endodermis is absent. Vascular bundles are encircled by fiber cells in three species. The mesophyll of most species consists of identically shaped cells, although palisade-like tissue has been observed in a few species. The epidermal cells vary from elongated to isodiametric and have either undulated or smooth anticlinal walls, which are deeply pitted in some species. The outer epidermal walls are usually thick and heavily cutinized. Stomates are distributed on both surfaces in 18 species, on the abaxial surface in 11 species, and on the adaxial side in only two species. Most stomates are practically isodiametric in surface view, broader than epidermal cells, usually parallel to the vein, and at the same level as the adjacent epidermal cell. A typical guard cell has a prominent outer ledge and a less developed inner ledge of cutin in most species. Six groupings are suggested, based on similarity of leaf structure and the known chromosome numbers.     

SURVIVORSHIP PATTERNS IN THREE SPECIES OF CAPTIVE CETACEANS

Survival rates for three species of captive cetaceans are reported, based on records of dates of capture, birth, and death of individual animals. The annual survival rate was 0.93 for bottlenose dolphins and killer whales and 0.94 for white whales. Confidence limits of these estimates are discussed. Differences in survival rates between institutions were significant for bottlenose dolphins only. Calf survival for bottlenose dolphins was lower than non-calf survival. Survivorship of male killer whales was significantly less than survivorship of female killer whales; sex-specific survival rates were similar for the other two species. Estimates of average or maximum longevity alone were not useful in comparing rates of survival. Because survival in the first year of captivity may be lower than subsequent years, estimates of the expected lifespan, based on data from the first few years of captivity, may be biased.     

两种锦鸡和环颈雉线粒体DNA(mtDNA)的比较研究

本文以10种限制性内切酶分析雉科中环颈雉,红腹锦鸡和白腹锦鸡线粒体DNA（mtDNA）。雉属与锦鸡属之间的遗传距离P为0.076（0.067-0.085）,红腹锦鸡与白腹锦鸡的P为0.012。推算雉属和锦鸡属的分化大约发生在3.8×10[6]年以前,红腹锦鸡与白腹锦鸡的分化大约在6×10[5]年以前。这些结果表明：1.在雉科系统发生中,雉属与锦鸡属是近缘的属;2.红腹锦鸡和白腹锦鸡的分化较晚,关系密切,可能只是两个亚种。     

3种十字花科植物的核型研究

３种十字花科植物的核型研究肖成汉,赵建伟,何凤仙（华中农业大学武汉４３００７０）关键词十字花科,菘蓝,芝麻菜,墙生二行芥,核型ＳＴＵＤＩＥＳＯＮＫＡＲＹＯＴＹＰＥＳＯＦＴＨＲＥＥＳＰＥＣＩＥＳＩＮＣＲＵＣＩＦＥＲＡＥ￥ＸｉａｏＣｈｅｎｇｈａｎ;Ｚｈａ...     

兰州北山三种蜥蜴春季食性分析

兰州地区密点麻蜥、丽斑麻蜥和草原沙蜥的春季食物均为动物食物。无论在栖息地重叠地区还是非重叠地区,三种蜥蜴的食物种类在种间均无显著差异（Ｆ＝０．８６１,ｄｆＴ＝２,ｄｆＥ＝３６,Ｐ〉０．０５）。种内不同性别和年龄食性无显著差异。     

VARIATIONS IN THE LEAF OILS OF THREE SPECIES OF JUNIPERUS

Leaf oils from Juniperus occidentalis, J. osteosperma, and J. califomica were analyzed qualitatively and quantitatively for characteristic chemical composition. Seasonal, diurnal, and local microcline variation was quantified. Neither microcline nor seasonal variation appeared to have a significant effect on the leaf oil composition, although some variation was observed. A definite trend toward diurnal cycling was detected and tentatively linked to air temperature fluctuation from dawn to dark.     

三种蝙蝠飞行状态下回声定位信号的比较

对马铁菊头烟、萨氏伏翼与白腹管鼻蝠在飞行状态下的回声定位信号进行了比较研究。结果表明：马铁菊头蝠的回声定位为长恒频一调频声（CF－FM）叫声（叫声持续时间均长于10ms）,具有两个谐波;萨氏伏翼与白腹管鼻蝠的回声定位均为宽频调频声（FM）叫声,叫声持续时间分别为3．0±1．3ms和3．6±3．0ms,具有两个或三个谐波。这些回声定位叫声的特性可能与它们所处的生境相适应。     

THE CONCHOCELIS PHASE OF THREE SPECIES OF PORPHYRA IN CULTURE

The Conchocelis phases of Porphyra perforata f. patens, P. cuneiformis and P. nereocystis were cultured from spores in a sterile artificial medium at 12 C and with 25 ft-c illumination for 10 hr daily. The cultures showed differences in duration of the vegetative phase, sporulation, liberation of spores, and the return to the leafy phase. Morphological differences were also noticed. Since the 3 species were grown under identical conditions, it is inferred that these characteristics are probably different for the 3 species studied.     

DETERMINING PREGNANCY FROM BLUBBER IN THREE SPECIES OF DELPHINIDS

We quantified progesterone in 110 blubber samples from dolphins of known reproductive status in order to test the accuracy of a method to determine pregnancy status in wild cetaceans. The samples were collected from fishery‐bycaught delphinids of three species (Delphinus delphis, Lissodelphis borealis, and Lagenorhynchus obliquidens). We ascertained that blubber progesterone concentrations could clearly distinguish pregnant D. delphis (range 132–415 ng/g, mean 261 ng/g) from non‐pregnant mature and immature ones (range 0.92–48.2 ng/g, mean 15.2 ng/g). We found similar dramatic differences in L. borealis and L. obliquidens. These results were insensitive to various blubber sampling depths and anatomical sampling locations on the body, suggesting relative homogeneity of progesterone levels throughout the blubber. However, no trend was found in blubber progesterone concentration with fetal length, indicating that although blubber progesterone appears to distinguish pregnancy status, it is unlikely to differentiate pregnancy stage. Based on the findings presented here we suggest that this method, when coupled with projectile biopsy procedures, can be used to assess the pregnancy status of free‐ranging cetaceans and thus provide a new tool to determine pregnancy rates of wild populations.     

番荔枝科10种植物叶表皮结构的研究

利用光学显微镜和扫描电子显微镜,对番荔枝科10种植物的叶表皮结构进行了观察,结果如下：表皮细胞近等径多角形或不规则形,垂周壁直,弧形,浅波状,波状或深波状,瓜馥木和香港瓜馥木叶片远轴面表皮细胞平周壁形成乳突,有的植物表皮细胞内具棱晶或晶簇,气孔器全部为平列型,具2－6个副卫细胞,除鹰爪花近轴面,远轴面均具气孔器外,其它9种植物的气孔器仅分布在远轴面,有的植物还具有双气孔器或败育的气孔器类型。除圆滑番荔枝外,其它9种的表皮均具表皮毛,表皮毛有单细胞毛,单列多细胞毛,2列多细胞毛,棍棒状毛和星状毛等类型,研究结果表明,10种植物的表皮细胞形状,垂周壁的式样,平周壁是否乳突,表皮细胞内晶体的有无及其类型,近轴面是否具气孔器,表皮毛的类型等方面存在着种间差异,这些特征可以作为种间甚至属间分类和系统关系探讨的依据。     

PHENOLOGY OF THREE ANT SPECIES IN THE SOLOMON ISLANDS

i
Seasonal variation in the composition of colonies is described, with particular reference to the incidence of sexual castes. The ant species are Oecophylla smaragdina F., Iridomyrmex cordatus Fr. Smith and Anoplolepis longipes Jerdon.