社鼠消化道长度和重量的季节变化

社鼠消化道长度和重量的季节变化ＳＥＡＳＯＮＡＬＶＡＲＩＡＴＩＯＮＳＩＮＬＥＮＧＴＨＡＮＤＷＥＩＧＨＴＯＦＤＩＧＥＳＴＩＶＥＴＲＡＣＴＩＮＲＡＴＴＵＳＮＩＶＩＶＥＮＴＥＲＣＯＮＦＵＣＩＡＮＵＳ关键词社鼠消化道形态季节动态ＫｅｙｗｏｒｄｓＲａｔｕｓｎｉｖ...     

突变体——侏儒小鼠(dw~t)与津白3(TA3)不同日龄骨骼、体重及体长的比较

侏儒小鼠与津白3体重的比值为1:2.5。它们的骨骼、休重、休长及尾长的测量均具非常显著或显著意义。经均衡性检验,不同日龄、不同性别间TA3/dw~t小鼠的不同骨骼、体重、体长及尾长的比值变化是均匀一致的。证明侏儒小鼠骨骼、体重、体长及尾长均系均匀缩小,是身体各部分匀称的侏儒小鼠。     

达乌尔黄鼠产热的季节性变化

达乌尔黄鼠（Ｃｉｔｅｌｌｕｓｄａｕｒｉｃｕｓ）的产热表现出明显的季节性变化。在非冬眠期,静止代谢率（ＲＭＲ）和非颤抖性产热（ＮＳＴ）于春季最高,秋季次之,夏季最低。冬眠期,ＲＭＲ降到极低水平,只为春季的３．０％。肝脏的线粒体蛋白含量、线粒体呼吸和细胞色素Ｃ氧化酶活力在秋季显著高于其它各季。褐色脂肪组织（ＢＡＴ）的重量、线粒体蛋白含量、细胞色素Ｃ氧化酶活力和α－磷酸甘油氧化酶活力,在夏季处于一年中的最低水平,到了冬季这些指标达到一年中的最高水平。在非冬眠季节ＢＡＴ产热能力升高时,ＮＳＴ能力也相应升高,这表明ＢＡＴ产热能力的增强是ＮＳＴ能力提高的部分机制。达乌尔黄鼠血清Ｔ＿４含量在年周期中没有明显改变,冬眠时血清Ｔ＿３含量显著高于其它各季。     

SEASONAL VARIATIONS IN RESERVE AND STRUCTURAL COMPONENTS OF PINUS RESINOSA CONES

Changes in reserve materials, lignin, hemicellulose, and cellulose of 1st-year conelets and 2nd-year cones of red pine (Pinus resinosa Ait.) were studied by chemical extraction of the respective fractions. During the first 11 months after emergence of conelets, reserve materials, primarily carbohydrates, constituted approximately half of the dry weight of cones. Cellulose and hemicellulose contents were low but cells were highly lignified. During summer of the 2nd year of cone development, marked compositional changes occurred. A rapid surge of cone growth, possibly triggered by resumption of pollen-tube growth and fertilization, occurred from mid-June to early August and was accompanied by transformation of reserve materials into cellulose and, to a lesser extent, into hemicellulose and lignin. During this transformation, the thickening and lignification of cells responsible for the opening of cone scales probably occurred. The developing seeds also mobilized readily available cone reserves during this time.     

禁食对小鼠体重、SOD和丙二醛含量的影响

给小鼠禁食4天后观察体重、肝SOD和心肌丙二醛的影响。结果表明,禁食期间小鼠的体重明显减轻,复食后体重很快恢复;肝脏SOD的活性明显提高,心肌丙二醛的含量显著下降。提示短期禁食具有抗衰老的效应,可提高机体的生存能力。     

上海淀山湖浮游桡足类群落组成与季节变动研究

本文报道了1984年2月至1985年2月上海淀山湖浮游桡足类的群落及优势种数量季节变动的调查结果．在淀山湖共获得11种浮游桡足类,隶属2目5科10属;根据各种类出现的月份,可以把这儿种桡足类划分成4种类型,终年出现型、夏秋季型、冬春季型和畏严冬型;在湖泊敞水区的浮游桡足类,年数量变动曲线有春季、夏季以及秋季三次高峰,秋季高峰比春季、夏季高峰更突出,持续时间约两个月;中华窄腹剑水蚤、汤匙华哲水蚤、广布中剑水蚤和近邻剑水蚤这4个优势种制约了桡足类群落总数量的季节消长。浮游桡足类生物量的季节变动有4次高峰,春季及秋季高峰出现时间迟于总数量高峰,其原因是数量高峰期桡足类群落中含有约80—90％的幼体,幼体成长之后方能达到生物量高峰期。本文还就影响浮游桡足类群落数量、生物量的生态因子作了初步的讨论。     

SEASONAL GROWTH AND NUTRIENT ECO-PHYSIOLOGY OF ECKLONIA RADIATA FROM DOUBTFUL SOUND, FIORDLAND, NEW ZEALAND

The kelp, Ecklonia radiata , dominates the sublittoral zone within the Doubtful Sound complex. Doubtful Sound is one of a series of fourteen fiords indenting the southwestern coast of the South Island, New Zealand. A feature of these fiords is the freshwater layer that resides atop the salt water, creating a unique marine environment. Mature sporophytes were collected from three sites (two outer sites towards the coastline and one site within the fiord) over a fourteen-month period (October 1998 to December 1999). Growth rates, measured using the hole punch technique, were greatest in spring at all three sites. The nutrient eco-physiology of mature E. radiata was investigated by measuring inorganic nitrogen (NO⁻³ and NH⁺⁴) uptake rates at eight concentrations (2–64 μM). Soluble tissue nitrogen (NO⁻³ and NH⁺⁴) and tissue carbon:nitrogen (C:N) ratios were also determined. At all sites, E. radiata showed higher uptake rates for ammonium than for nitrate. In winter, soluble tissue nitrogen was lower at the two outer sites compared to the inner site, while in summer, levels at all sites were similar but had decreased from the winter values. C:N ratios greater than 20 were observed at all sites, increasing in summer to a peak in autumn, suggesting E. radiata may be nitrogen limited, particularly in late summer. Environmental parameters (photon flux density, water temperature, rainfall and wind) were measured, as was sea water velocity around the primary blade of E. radiata , and multivariate correlations used to determine which (if any) environmental parameter exerted greatest influence on eco-physiological parameters accessed.     

THE SCALING OF PLANT AND ANIMAL BODY MASS,LENGTH, AND DIAMETER

The interspecific scaling exponents of body mass M and diameter D with respect to length L were determined to evaluate the predictions of three scaling hypotheses (geometric, stress, and elastic similitude). The relation between M and L was determined for data from a total of 133 aquatic and terrestrial species (66 plant and 67 animal species); the relation between D and L was determined independently for a total of 753 aquatic and terrestrial species (667 plant and 86 animal species). Organisms were crudely classified as to their geometry (spheres, spheroids, cylinders) and shape (defined as the body slenderness factor, L/D) to examine whether geometry and shape evinced size-dependent variations. Regression indicated M = 1.29L^2.95 (r² = 0.91, N = 133; α_RMA = 3.09 ± 0.088). The stress and elastic similitude (which respectively predict α_RMA = 5 and α_RMA = 4) were rejected; geometric similitude was not (α_RMA = 3). For animals and plants, α_RMA = 2.81 ± 0.061 (r² = 0.98), and α_RMA = 2.95 ± 0.093 (r² = 0.94), respectively. For aquatics and terrestrial organisms, α_RMA = 2.82 ±0.134 (r² = 0.97, N = 36), and α_RMA = 3.08 ±0.111 (r² = 0.89, N = 97), respectively. These results were interpreted to support the hypothesis of geometric similitude. For the pooled plant and animals data, D = 0.05L^1.00 (r² = 0.95; α_RMA = 1.03 ± 0.009), which was compatible with the hypothesis of geometric similitude. For plants, D = 0.05L^1.06 (r² = 0.95; α_RMA = 1.09). For animals, D = 0.29L^0.98 (r² = 0.95; α_RMA = 1.01 ± 0.025). Also, for aquatics, α_RMA = 0.951 ± 0.151, whereas for terrestrial plants and animals, α_RMA = 1.03 ± 0.089. Although the scaling exponent for D differed among individual groupings of animals and plants, the results of regression analyses were interpreted to indicate that, on the average, body diameter scaled isometrically with respect to length as predicted by geometric similitude. For the pooled data set, organic shape varied over 3 orders of magnitude; L varied over 9 orders of magnitude reflecting 22 orders of magnitude of M. In terms of body geometry and the absolute numbers of species in the total data set: spherical shaped species (L = D) < unassigned species < prolate spheroidal species < cylindrical (squat < slender) species. The largest organisms in the data set were slender (L/D > 20) cylindrical plants; the smallest organisms were spherical plants and animals. Although not subject to statistical inference, these data were interpreted to indicate that organic shape and geometry evince size-dependent variations. These variations as well as size-dependent changes in bulk density are hypothesized to account for the scaling exponents of M and D determined for individual plant and animal clades and grades.     

SEASONAL VARIATIONS OF PHOTOSYNTHETIC PIGMENTS, TOTAL C, N, AND P CONTENT, AND PHOTOSYNTHESIS IN PHYLLARIOPSIS PURPURASCENS: (PHAEOPHYTA) FROM THE STRAIT OF GIBRALTAR

Photosynthetic pigments, C, N, and P tissue composition, and photosynthetic rate were measured from April to October in the brown alga Phyllariopsis purpurascens (C. Agardh) Henry et South (Laminariales, Phaeophyta) growing at a 30-m depth in the Strait of Gibraltar. Ir-radiance reaching the population ranged from 13.5 to 27.5 mol.m^-2.mo^-1. The available light for this species, expressed as a percentage of the irradiance above the water, was 1.8%. Dissolved inorganic nitrogen forms, NO3-and NH₄+, were constant from April to October, whereas phosphate was depleted in August. Chlorophyll a decreased from 520.0 ± 165.0 to 199.6 ± 159.9 μg.g^-1 dry weight; in contrast, chlorophyll c and carotenoids did not change until September but increased threefold in October. C:N and N:P ratios changed in the same way and in the same range. They were constant until July but increased from 15–17 up to 42 (C:N) and from 14 to 40 (N:P) in October, suggesting a severe P limitation of growth of this species. The dark respiration rate and the light compensation point were constant from April to October (0.5 ± 0.1 μmol O₂. m^-2.s^-1 and 6.5 ± 0.2 μmol.m^-2. s^-1, respectively), whereas the maximum rate of apparent photosynthesis, light onset saturation parameter, and half saturation constant for light were maximum in April to May (3.7 μmol O₂. m^-2.s^-1and 40 and 41.5 μmol.m^-2. s^-1, respectively) and October (3.6 μmol O₂. m^-2.s^-1 and 50 and 53.7 μmol.m^-2. s^-1, respectively). They were minimum in August (1.2 μmol O₂.m^-2.s^-1 and 11.3 and 12 μmol.m^-2.s^-1, respectively). These minimum figures yielded a negative carbon budget in August and 0 in September, whereas it was positive the rest of the year. Photosynthetic efficiency, estimated by the ratio between maximum apparent photosynthesis and light half saturation constant, showed a strong agreement with productivity measured by means of an independent method. These results indicate that lamina expansion in this species is controlled by photosynthetic efficiency.     

北京地区大葱和玉米根际VA菌根的季节变化及其与环境因子之间的关系

1986-1987年连续两年系统调查了北京地区大葱(Allium fistulosum L.)和玉米(Zeamays L.)根际 VA 菌根侵染百分率及菌根真菌孢子密度的季节变化。分析了菌根和菌根真菌的发生与几种土壤因子(土壤硝态氮、铵态氮、速效磷和有机质含量,土壤 pH 值)和气候因子(气温、积温、土温、光照、降水量,相对湿度等)之间的关系。结果表明:大葱和玉米的侵染百分率随作物生育期的增长而增加,并以6月和9月的增长速度最快。一年中,植物根际菌根真菌的孢子密度有二个高峰,分别在6-7月和10月。在北京的同一地区,一年中,几种测定的土壤因子变化很小,因此,认为气候因子对菌根发生的季节变化具有更大的影响。用线性相关和关联度分析的结果表明:一年中,菌根的发生与积温的关系最为密切。     

七种鼠科啮齿动物消化道长度和重量的比较

测定浙江省金华地区7种鼠科啮齿动物的总消化道及各消化器官的长度和重量,与其食性和生境作比较,旨在检测近缘种之间消化道长度和重量的差异,家栖种类与野栖种类消化道形态的差异,野外捕获动物带回实验室处死,解剖分离消化道为胃,小肠,盲肠和大肠,精密直尺测定各器官的平展长度,纵剖肠道,生理盐水冲净内容物,65℃恒温干燥后称得干重,研究结果表明,消化道长度的种间差异明显大于消化道重量的种间差异;盲肠和大肠长度的种间差异明显大于小肠长度的种间差异,植食性野栖种类的胃,盲肠和大肠大于杂食性家栖种类,而两类动物小肠长度的差异不明显。     

VARIATIONS IN ENVELOPE MORPHOLOGY AND MINERALIZATION IN TRACHELOMONAS LEFEVREI (EUGLENOPHYCEAE)1

The mineralized envelope surrounding the trachelomonad cell is a complex of organic and inorganic components, anastomosed to form a structure that is characteristic of the species. Although there may be considerable morphological variability in envelope size, shape and ornamentation, its microarchitecture is characterized by two basic components: granular and needle-like deposits. The present study documents for the first time that manipulation of the culture conditions results in predictable changes in envelope ultrastructure, color and elemental composition. Supplemental iron (Fe) in the culture medium results in an increase of granular components in the envelope, whereas supplemental managanese (Mn) results in an increase of needle-like components; with nitrogen (N) supplements there is an increase of both granular and needle-like components in the envelope. It is also shown here that autoxidation of Fe may occur, resulting in the accumulation of Fe deposits along strands of unmineralized envelope mucilage. Autoxidation and deposition of Mn do not occur.