二斑叶螨为害对菜豆生理指标的影响

二斑叶螨(Tetranychus urticae)是为害菜豆的重要害虫。本文研究了二斑叶螨不同密度和不同时间为害对菜豆各种生理指标的影响。结果表明:在二斑叶螨2头·叶-1的低密度和为害少于5 d的短时期内,菜豆叶片叶绿素a、叶绿素b和叶绿素总含量变化不大,但随着二斑叶螨为害时间的延长和密度的增大,叶绿素含量下降明显增加;总糖和还原糖的含量与二斑叶螨的为害程度关系密切,即为害时间越长、受害程度越严重,还原糖降低幅度越大,总糖的含量则先升高再降低;随着二斑叶螨为害程度的加重,菜豆叶片中全磷、全钾损失显著,全氮含量变化不显著。     

毛竹受密竹链蚧危害导致其生理生化指标影响的研究

通过比较毛竹林受密竹链蚧不同程度危害后叶片中叶绿素、总糖、还原糖、蛋白质含量及含水量的差异,结果表明,毛竹受密竹链蚧危害后毛竹叶片生理生化指标与正常叶片存在显差异。     

竹缺爪螨生态学初步研究

本报道严重危害毛竹生长和害螨－－竹缺爪螨在不同温度下生长,发育历期以及在竹林间种群动态。结果表明：在20－35℃范围内随着温度升高其发育历期缩短,温度与发育历期呈直线回归关系：Y全代＝651573-1.6250X（=-0.98);光照是影响竹缺爪螨的卵,幼螨存活及成螨产卵量的重要因素。在竹林间,毛竹换叶,降雨量,天敌数量是影响竹缺爪螨种群消长的和重要因素,最后提出综合防治的措施。     

马六甲肉食螨对害嗜鳞螨捕食效应研究

本首次报道马六甲肉食螨Cheytetns malaccensis对贮存物中重要害螨,害嗜鳞螨的捕食效应研究。马六甲肉食螨的雌螨、雄螨、前若螨、后若螨对害嗜鳞螨的成螨的功能反应均属Holling Ⅱ型。温度对马六甲肉食螨捕食影响较大．在12-29℃范围内随着温度上升其捕食量增加,其直线回归方程为Y=-1.0964 0．5084X(r=0．9765)。在猎物密度不变情况下,马六甲肉食捕食猎物的数量是随着自身密度的增加而下降,其方程为A=16．546^0.5425(r=0．9699)．用寻找效率a与处理时间Th之比a/Th来衡量天敌对害虫控制能力．其值越大则控制猎物能力就越强。因此本试验表明：马六甲肉食螨控翩害嘈鳞螨的能力是雌>雄螨>前着螨>后若螨。     

福建茶树害螨发生动态及其与茶树品种理化特性的相关性分析

用5点采叶取样法调查了茶树害螨发生特点。结果表明:各茶树品种的害螨盛发高峰期一般都出现在8月底到9月初;对2005年5品种茶树上害螨螨情指数高峰期进行方差分析,结果表明均达到极显著差异(F=4.141,P=0.0054)。对不同茶树品种的叶片理化指标与螨情指数进行相关分析,结果表明:叶片厚度与相应品种的螨情指数之间呈一定的负相关关系(F=0.3903,r=-0.4040);不同茶树品种的叶片下表皮及其角质层厚度和相应品种的螨情指数之间呈一定的正相关关系(F=2.40,r=0.7389);不同茶树品种叶片的咖啡因和GC含量与害螨螨情指数呈负相关,相关关系接近显著水平(F=3.44,r=-0.7309和F=5.96,r=-0.8156)。     

苹果果实中几种生化物质的含量与抗采后炭疽病的关系

接种炭疽菌前与苹果果实品种的病情指数呈正相关的生化物质是果实中的可溶性总糖含量(r=0.9978),负相关的生化物质是果实中的木质素(r=-0.9811)和绿原酸含量(r=-0.9939),接种前果实的总酸含量与品种的病情指数无关;接种后48和96 h的寄主体内可溶性总糖和有机酸含量有增有减,病情指数不同的品种变幅不同,接种96 h后果实中总酸含量与品种的病情指数呈现负相关(r=-0.9412),木质素和绿原酸含量都呈上升趋势,抗病品种的增幅高于感病品种。     

从实验种群生命表参数评价胡瓜钝绥螨控制毛竹害的能力

本文报道胡瓜钝绥螨Amblyseius cucumeris Oudemans在25℃条件下以毛竹4种害螨南京裂爪螨chizotetranychus nanjingensis Ma&Yuan、竹裂爪螨S.bambusae Reck、竹缺爪螨Aponychus corpuzae Rimando、竹刺瘿螨Aculus bambusae Kuang为猎物的实验种群生命表,并进行比较结果表明:①胡瓜钝绥螨能取食上述4种害螨,其世代存活率依次为90.4%、77.55%、87.93%、81.63%;②每雌总产卵量依次为38.12粒、45.77粒、35.59粒、30.76;③胡瓜钝绥螨以南京裂爪螨为猎物其净增殖率R0=16.74低于南京裂爪螨(R0=20.84),但是内禀增长率rm=0.154是猎物的1.73倍(rm=0.089),世代周期T=18.31和种群倍增时间t=4.5088均低于南京裂爪螨(T=33.35,t=7.704),因此在林间当南京裂爪螨离巢、破巢或大量迁移时能有效地控制其种群增长;④胡瓜钝绥螨以竹裂爪螨为猎物其净增殖率R0=25.81,内禀增长率rm=0.152,周限增长率λ=1.164均低于竹裂爪螨(R0=39.28、rm=0.192、λ=1.212),而世代周期T=21.35种群倍增时间t=4.552均高于竹裂爪螨(T=19.08,t=3.603)因此必须在竹裂爪螨处于低密度时释放胡瓜犯绥螨才能有效地控制其种群密度的增长;⑤胡瓜钝绥螨以竹裂爪螨为猎物时,其净殖率R0=20.80,内禀增长率rm=0.175,周限增长率λ=1.191均略低于竹裂爪螨(R0=21.54、rm=0.185、λ=1.202),而世代周期T=17.30种群倍增时间t=3.958均略高于竹裂爪螨(T=16.62,t=3.753)因此必须在竹裂爪螨处于低密度时释放胡瓜钝绥螨才能有效地控制其种群密度的增长;⑥胡瓜钝绥螨以竹刺瘿螨为猎物时其净增殖率R0=16.82与取食南京裂爪螨相近,但内禀增长率rm=0.144,周限增长率λ=1.155均低于取食上述三种叶螨,但产卵量高于其乡土天敌竹盲走螨(Tylodromus bambusae),林间在竹刺瘿螨低密度时仍能控制竹刺瘿螨的种群密度.模拟试验表明当毛竹长至1米高时释放胡瓜钝绥螨16小时后,能在12米高的竹冠上发现大量的胡瓜钝绥螨.研究结果表明胡瓜钝绥螨能有效地控制毛竹害的危害.     

小麦穗分化期间叶片和幼穗含糖量及转化酶活力的变化

小麦穗分化期间叶片中酸性转化酶和总糖含量随小花分化总数的增加而增加,还原糖含量在小花出现前递增,小花出现后变化不明显。幼穗中酸性转化酶较稳定,其酶活力和成熟时的粒数显著相关(r=0.7488~*)。幼穗的总糖含量及幼穗鲜重随小花分化进程加快呈对数曲线上升。还原糖含量很低,且变化不大。     

天敌竹盲走螨在纯竹林中种群数量锐减的原因研究

本项研究针对我国南方毛竹林,近年害螨突发性成灾的现象,进行调查与研究,结果表明：纯竹林害螨总量平均高于混交林289．28％,混交林天敌竹盲走螨(Typhlodromus bambusae Ehara)总量平均高于纯竹林263．56％;混交林益、害螨比例为1：13,而纯竹林益、害螨比例是1：118。研究表明纯竹林地面垦复、劈草,使得以芒草为生的芒草裂爪螨(Schizotetranychus mistanthi Saito)种群数量急剧下降,导致乡土优势种竹盲走螨缺乏中间食物,难以维持种群。在毛竹——芒草混生的毛竹林(含其它树种)由于毛竹上害螨和林下芒草裂爪螨受到共同天敌——竹盲走螨的控制维持着稳定的益、害种群数量,虽然有害螨,但不成灾,在纯竹林由于地面垦复、劈草破坏原有已形成的生物链,导致毛竹害螨失去天敌控制而突发性成灾,证明纯竹林中天敌锐减是导致毛竹害螨暴发成灾的重要因素。     

模拟酸雨对朱砂叶螨寄主植物三月早茄生理生化的影响

以朱砂叶螨的寄主植物三月早茄为对象,研究了不同pH值和不同时间模拟酸雨胁迫下,茄子对酸雨的抵抗、适应能力和营养物质含量变化.结果表明,随酸雨酸度增强,茄叶的过氧化氢酶(CAT)活性、磷和可溶性蛋白含量呈单峰变化趋势;而过氧化物酶(POD)活性、可溶性糖含量呈单谷变化趋势;还原糖含量和超氧化物歧化酶(SOD)活性随酸度增加呈上升趋势;茄叶pH值呈下降趋势,含水量不受酸雨影响.POD对酸雨作用反应迟缓,而SOD、CAT较敏感,其他几项生理指标则对酸雨作用时间反应灵敏.高pH(4.0～5.6)的酸雨刺激茄叶的保护能力增强,促进茄叶的生长发育.由于茄叶内糖含量、磷及可溶性蛋白含量的改变,植物的适口性有所变化,可促进叶螨生长,而在强酸性酸雨(pH＜3.0)胁迫下,植物的生长受到抑制,营养物质含量降低,抑制朱砂叶螨的生长.     

Ectogenesis and the case against the right to the death of the foetus

Ectogenesis, or the use of an artificial womb to allow a foetus to develop, will likely become a reality within a few decades, and could significantly affect the abortion debate. We first examine the implications for Judith Jarvis Thomson’s violinist analogy, which argues for a woman’s right to withdraw life support from the foetus and so terminate her pregnancy, even if the foetus is granted full moral status. We show that on Thomson’s reasoning, there is no right to the death of the foetus, and abortion is not permissible if ectogenesis is available, provided it is safe and inexpensive. This raises the question of whether there are persuasive reasons for the right to the death of the foetus that could be exercised in the context of ectogenesis. Eric Mathison and Jeremy Davis have examined several arguments for this right, doubting that it exists, while Joona Räsänen has recently criticized their reasoning. We respond to Räsänen’s analysis, concluding that his arguments are unsuccessful, and that there is no right to the death of the foetus in these circumstances.     

On the diversity of the Cladocera in the tropics

The mythical concept of an impoverished tropical cladoceran fauna is refuted. On a planetary scale, around half of the cladoceran species presently known occur exclusively in the tropics-subtropics, often with considerable restriction to particular geographical subzones. On a regional (political) scale, the situation is often unclear because of the continued fragmentary nature of studies, and because political units are not a good basis for biogeographical comparisons. At the finest level of resolution (lake-perlake comparisons), there appears to be an upper limit of c. 50 cladoceran species per individual lake. No significant difference between lakes in the temperate zone and in the tropics could be established here. Daphnia is largely absent from the tropics, but is replaced by more Sidids, Moinids, and Bosminids, such that the average cladoceran community in the limnetic zone of a tropical lake is not characterized by less species but rather by lower population densities. This, in turn, is considered a consequence of higher prevalent predation levels in the tropics.     

Tubular networks in the terminal endings of the visual receptor cells in the human,the monkey,the cat and the dog

Summary A tubular network was found in the terminal endings of the visual receptor cells in the human, the monkey (Macaca mulatta), the cat and the dog. These tubules are arranged in close groups in the vicinity of the synaptic lamellae and the invaginated dendrites. According to the form, diameter, density of the tubules and to the consistence of the network formed by them one can distinguish at these places an initial type (type I), a transitory (type II) and a vesicular one (type III). In the the type III branching, bizarre forms are frequent. The diameter of all the tubules reaches 500–600 Å, their density and walls being the same as in the synaptic vesicles.Similar networks also occur in the axons of the visual receptor cells of the monkey.

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Zusammenfassung In den Endigungen der Photorezeptorzellen von Mensch, Affe (Macaca mulatta), Katze und Hund kommen aus Tubuli bestehende Komplexe vor. Organellenartig in geschlossenen Gruppen angeordnet, liegen sie in Nähe der synaptischen Lamellen und der invaginierten Dendriten. An diesen Stellen kann man nach Form, Durchmesser, Dichte und Konsistenz der von den Tubuli gebildeten Komplexe drei Typen unterscheiden: 1. einen initialen (Typus I), 2. einen Übergangstypus (Typus II) und 3. einen vesiculären Typus (Typus III). In letzterem kommen häufig verzweigte, bizarre Formen vor. Der Durchmesser sämtlicher Tubuli erreicht 500–600 Å. Ihre Dichte und ihre Wand gleicht denen der synaptischen Vesikel.Ähnliche Komplexe fanden wir auch in den Axonen der Photorezeptorzellen vom Affen.

     

Assessing the Physiological State of the Fucoids from the Barents Sea Littoral by the End of the Polar Night

Methods of amperometry and potentiometric titration were used to follow dark respiration (DR) and apparent photosynthesis (AP) in the fucoids Ascophyllum nodosum (L.) Le Jol, Fucus vesiculosus L., and F. serratus L. from the Barents Sea littoral by the end of the 40-day-long polar night. The macroalgae were shown to manifest species-specific low rates of photosynthesis and respiration. However, in spite of their low photosynthetic status due to the effects of subzero temperature and prolonged low or zero illumination, the macroalgae have been able to restore DR and AP to the initial level already by the day 9; the ability to restore AP depended on the level of illumination. The study of the changes in the carbonate–bicarbonate system in the light and darkness demonstrated that the macroalgae grown in darkness, in contrast to those grown in twilight, could absorb bicarbonate in darkness; however, they lost this capacity after two-day-long illumination at an irradiance of 7 mol/(m² s). Bicarbonate uptake in darkness and the capacity to restore the systems of photosynthesis and respiration in fucoid cells are discussed in the context of algal energy metabolism under the polar night conditions.     

Arranging the elements of the potassium channel: the T1 domain occludes the cytoplasmic face of the channel

The voltage-gated potassium channel is currently one of the few membrane proteins where functional roles have been mapped onto specific segments of sequence. Although high-resolution structures of the transmembrane portions of three bacterial potassium channels, the tetramerization domain and the cytoplasmic ball are available, their relative spatial arrangement in mammalian channels remains a matter of ongoing debate. Cryo-electron microscopic images of the six transmembrane voltage-gated Kv channel have been reconstructed at up to 18 Å resolution, revealing that the T1 domain tetramerizes and is suspended below the transmembrane segments. However, the resolution of these images is insufficient to reveal the location of the third piece of the puzzle, the inactivating ball domain. We have used the aberrant interactions observed in a series of chimæric channels to establish that an assembled T1 domain restricts access to the cytoplasmic face of the channel, suggesting that the N-terminal ball and chain may be confined in the space between the T1 domain and the transmembrane portion of the channel.     

Observations on the permeability of the choriocapillaris of the eye

Summary The choriocapillaris is a fenestrated capillary bed located posterior to the retinal pigment epithelium. It serves as the main source of supply to the photoreceptors, retinal pigment epithelium, and other cells of the outer retina. The permeability of these capillaries to intravenously injected ferritin (MW — approx. 480,000; mol. diam. 11 nm) was examined in the mouse, rabbit, and guinea pig, each of which is characterized by a different type of retinal vascularization. In all three species, the bulk of the ferritin remained in the capillary lumina, where it appeared to be blocked at the level of the diaphragmed fenestrae. Some ferritin was present in endothelial cell vacuoles. The results confirm previous work on the rat choriocapillaris and indicate that the barrier function of the choriocapillary endothelium is present even among species in which the retinal circulation differs significantly.Supported by NIH grant EY03418     

Separation of the pineal vesicle from the wall of the third ventricle during the post-hatching development of the chicken

Summary According to light- and electron-microscopic observations the pineal organ of the 3-day-old chicken consists of a prominent end vesicle and a tapering parenchymal stalk. During this stage the pineal lumen is in open communication with the third ventricle. However, in the 40-day-old chicken, which still possesses a well-developed end vesicle, the proximal portion of the pineal stalk displays regressive changes leading to local fragmentation. At this stage the pineal stalk is reduced, and the pineal lumen is missing. In 1-year-old chickens the parenchyma of the proximal portion of the stalk is further diminished, and in 3-year-old domestic fowl is completely displaced by bundles of collagenous fibers, only some nerve fibers being present. This post-hatching pineal development may reflect the sequence of changes leading from pineal sense organs to pineal glands.This work was supported by a grant-in-aid for Scientific Research from the Ministry of Education, Science and Culture of Japan