对冷适应大鼠棕色脂肪和肝脏在非寒颤产热机制中作用的评价

本实验主要观察并比较了大鼠冷适应前后直肠温度(RT)、血清游离脂肪酸(SFFA)浓度、肩胛间棕色脂肪组织(IBAT)和肝脏cAMP含量的变化及其对去甲肾上腺素(NE)反应性的改变。结果表明:①冷适应28d大鼠在冷环境中RT稳定,NE刺激后RT上升幅度大于常温对照组(P<0.005);②冷适应1d组SFFA升高,冷适应28d组SFFA接近对照组,且对NE刺激无反应,对照组给NE后SFFA与RT一致性升高;③冷适应28d组IBAT的cAMP升高,而肝脏的cAMP含量三组间无显著性差异。NE刺激后,冷适应28d组IBAT和肝脏cAMP均升高,与RT反应一致,而对照组不变。结果提示,在5±3℃适应28d的大鼠已建立冷适应机制,非寒颤产热(NST)容量增加,在冷适应的不同时期,肝脏和IBAT调节NST的机制不同。     

内蒙古库布齐沙地四种啮齿动物非颤拌性产热的季节变化

为了解非颤抖性产热在内陆荒漠小型哺乳动物适应性热能调节中的作用,1997年对库布齐荒漠沙地环境4种啮齿动物：三趾跳鼠（Dipus sagitta)、子午沙鼠（Meriones meridianus)、小毛足鼠（Phodopus roborovskii)和黑线仓鼠（Cricetulus barabensis)的非颤抖性产热季节变化进行了测定。4种动物的非颤抖性产热在秋季低温刺激下明显高于夏季,而且小毛足鼠和黑线仓鼠在秋季的最大非颤抖性产热分别高于春季14％和35％。典型荒漠种小毛足鼠的季节变化最明显,夏季最低。结果表明,生活在内陆干旱地区的动物生长期进化过程中,发展了良好的非颤抖性产热体温调节机制适应环境温度的季节变化。     

NEAR-VESSELLESSNESS IN EPHEDRA AND ITS SIGNIFICANCE

Wood of two specimens of Ephedra from high alpine localities is nearly vesselless: E. gerardiana from 4,750 m in Tibet, and E. rupestris from 4,300 m in Argentina. Ephedra gerardiana from lower elevations in the Himalayas has more vessels, although even there they are not abundant. Instances in other species of Ephedra in which extensive areas of latewood or even entire growth rings are vesselless are cited; these tend to occur in high deserts with climates somewhat less extreme than those of the alpine localities. Near-vessellessness is interpreted as an adaptive condition in which the proportion of tracheids, conductively safer than vessel elements, reaches a maximum. Near-vessellessness in Ephedra wood is probably reversible within limits, and should be likened to production of latewood to the exclusion of earlywood. Comparisons are offered to dicotyledons in which abundance of vessels is lowered with respect to ecological extremes.     

花柱卷曲性异交机制及其进化生态学意义

 有花植物具有纷繁复杂的繁育系统,以避免或促进自交或异交。花柱卷曲性异交机制(Flexistyly)是最近在热带山姜属(Alpinia)植物中发现的一种促进异交的行为机制。具有这一机制的种类其自然种群中的个体根据开花行为的不同分为两种表型：一种上午散发花粉而其柱头向上反卷,远离昆虫拜访的通道;另一种其柱头上午垂向唇瓣,能够接受拜访昆虫的传粉,但自身的花药却不打开。到中午时分,两种表型花通过互为相反的柱头卷曲运动转换性别——前者柱头向下卷曲,后者柱头向上卷曲且花药打开。每朵花的花期为12 h,两种表型在自然种     

NEW MATERIAL OF AZYGOGRAPTIDAE AND ITS SIGNIFICANCE

Among the graptolites collected by Unit 734 from the Lower Ordovician Qiaotingzi Formation (corresponding to the Ningkou Formation) at Xiayanzhai of Jishou, Hunan, more than ten specimens particularly chosen from the collection were handed over to the writer for. study. These spe cimens preserved as mere carbonaceous films in grey green slate belong to one new genus and the same new species named by the writer Jishougraptus mui gen. et sp. nov. in association with Didymograptus cf. praenuntius     

SOUND AND ITS SIGNIFICANCE FOR LABORATORY ANIMALS

1. Several methods of varying accuracy have been used to assess what sounds small laboratory animals such as rodents are capable of hearing. Most rodents can detect sounds from 1000 Hz (the frequency of the Greenwich Time Signal) up to 100000 Hz, depending on the strain, with usually one or more commonly two peaks of sensitivity within this range. Dogs can detect sound most easily from 500 Hz to 55000 Hz, depending on the breed. 2. Rodents also produce sound signals as a behavioural response and for communication in a variety of situations. Ultrasonic calls in the range 22000–70000 Hz are the main communicating pathway during aggressive encounters, mating, and mothering. Similar calls have also been recorded from isolated animals associated with inactivity, rest and possibly even sleep. 3. Very loud sounds cause seizures in rats and mice, or can make them more susceptible to other sounds later in life. This effect is possible even when animals are fully anaesthetized. Sound tends to startle and reduce activity in several species of animal. Even offspring of mice that have been sound-stressed exhibit abnormal behaviour patterns. Sounds also elicit various responses in rats from increasing aggression to making them more tolerant to electric shocks. 4. Levels of sound above 100 dB are teratogenic in several species of animals and several hormonal, haematological and reproductive parameters are disturbed by sounds above 80 dB. When rats are chemically deafened the disturbance to their fertility disappears. Lipid metabolism is disrupted in rats when exposed to over 95 dB of sounds, leading to increases in plasma triglycerides. Atherosclerosis can be produced in rabbits by similar levels of sound. 5. It has also been shown in guinea pigs and cats that hearing damage is governed by the duration as well as the intensity of the sound and is irreversible. Work on chinchillas hs demonstrated that sounds above 95 dB lead to this injury, but that sounds of 80 dB have no permanent effect on hearing sensitivity.     

白蚁翅面的微刻点及其意义

本文首次描述了在扫描电镜下观察到的22种主要采自浙江省的白蚁(隶属4科11属)的翅面微刻点,然后讨论了白蚁翅面微刻点的进化学,分类学,生物学和生态学意义．     

独叶草属的胚胎学及其系统学意义

独叶草属的胚乳发育为五福花型,其早期分化属细胞型;胚胎发育为石竹型下的独叶草亚型;珠 被内层的部分细胞形成栅栏组织状,最后消失或近于消失;反足细胞宿存,部分不育大孢子宿存并和部 分珠心组织一起形成珠孔塞状结构。这些性状表明它与星叶草属间的相似性要大于与毛茛目其它成员 间的相似性。     

HYBRIDIZATION BETWEEN ASTER AND MACHAERANTHERA AND ITS TAXONOMIC SIGNIFICANCE

A controlled crossing program resulted in the production of four interspecific and three intergeneric hybrids among species of Aster sect. Oxytripolium and Machaeranthera. Meiotic analysis revealed stronger degrees of genome homology in some of the intergeneric hybrids than in some of the interspecific hybrids. The significance of these results to the taxonomy of Aster and Machaeranthera was considered and the result was the transfer of Aster sonorae to Machaeranthera.     

栝楼属花粉形态研究及其在分类学上的意义

本文收集了国内外栝楼属Trichosanthes 31种1变种,在光学显微镜和扫描电镜下,进行了花粉粒形态的比较观察。该属花粉粒为3孔沟型,外壁表面纹饰可分为四个类型,即：疣状或皱波状(小苞组),粗网状(大苞组),细网状或光滑(叶苞组),近光滑或皱波状(王瓜组)。这四个类型的划分与植物形态分类基本一致,可作为分组及分种的依据之一。花粉特征支持将叶苞组分为叶苞亚组和柔毛亚组,如叶苞亚组有明显的沟,而柔毛亚组没有。     

植物根系分泌及其在林业中的意义

本文简要介绍了植物根系分泌物的成分、数量, 充分讨论了根系分泌的影响因素、根系分泌的部位及根系分泌物在土壤中扩散的范围, 并阐明了树木通过根系分泌对土壤营养条件、土壤微生物及其它相邻植物均有显著的影响。     

山茶科花粉超微结构及其系统学意义

借助光学显微镜,扫描电镜及透射电镜对分布于亚洲,北美洲及中南美洲山茶科１７属约５０种植物的花粉进行了系统的观察研究。本科花粉为３孔沟或３孔沟,近扁球至近球形,少数近长球形。大小从１３￣５０μｍ×５５．３μｍ。表面纹饰可分为皱波状,颗粒状,疣状,钝刺状,网状,穴网状及近乎光滑等类型。在皱波状纹饰中,其皱脊的组成分子可分为颗粒,念珠状结构。外臂为具复盖－柱状层结构,复盖层－穿孔或不穿孔。其复盖层、柱状