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1.
&#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &#  &# 《水生生物学报》2014,38(2):298-303
观察了实验室养殖条件下齐口裂腹鱼稚鱼鳞片的发生和覆盖过程。结果表明,稚鱼体长为30.732.3 mm时,鳞片最先出现在鳃盖后缘侧线处;体长为45.347.9 mm时,鳞片覆盖完毕,体长和日龄对鳞片覆盖均有显著影响。在鳞片覆盖过程中出现6个鳞片发生起始位置,依次是鳃盖后缘侧线处、尾柄部侧线处、臀鳍基部、腹鳍基部、背鳍基部和峡部。此外,组织切片的观察结果表明,齐口裂腹鱼鳞片发育主要经历了形态发生早期、形态发生晚期、分化早期、分化晚期和折叠期五个阶段。这些研究结果丰富了齐口裂腹鱼早期发育的生物学资料,将有助于了解其在系统学和功能形态学上的特征。    相似文献   

2.
矢尖蚧及其主要天敌空间格局研究   总被引:1,自引:1,他引:0  
  相似文献   

3.
观察了实验室养殖条件下齐口裂腹鱼稚鱼鳞片的发生和覆盖过程。结果表明,稚鱼体长为30.7—32.3 mm时,鳞片最先出现在鳃盖后缘侧线处;体长为45.3—47.9 mm时,鳞片覆盖完毕,体长和日龄对鳞片覆盖均有显著影响。在鳞片覆盖过程中出现6个鳞片发生起始位置,依次是鳃盖后缘侧线处、尾柄部侧线处、臀鳍基部、腹鳍基部、背鳍基部和峡部。此外,组织切片的观察结果表明,齐口裂腹鱼鳞片发育主要经历了形态发生早期、形态发生晚期、分化早期、分化晚期和折叠期五个阶段。这些研究结果丰富了齐口裂腹鱼早期发育的生物学资料,将有助于了解其在系统学和功能形态学上的特征。  相似文献   

4.
The cells of synurophyte flagellates (algal class Synurophyceae, formerly included in the Chrysophyceae) are enclosed within a regularly imbricate layer of ornamented siliceous scales. Scale morphology is of critical taxonomic importance within this group of algae, and the scales are valuable indicator microfossils in paleolimnological studies. The data presented here demonstrate that scale morphology and the integrity of the scale layer can exhibit extreme variability in culture as a function of the cellular quota of silica under silica-limited growth. Silica-limited, steady-state populations of the colonial flagellate Synura petersenii Korsh. were maintained over a range of specific growth rates (μ= 0.11–0.69 days?1) and silica cell quotas (Qsi= 0.13–2.40 pmoles Si · cell1). Scale morphology and the organization of the scale layer became increasingly aberrant as silica stress increased. Under severe stress, scale deposition was completely suppressed so that cells appeared scale-free. This depression of scale deposition was reversible; populations of silica-starved, scale-free cells rapidly regenerated new scale layers when placed in batch culture and spiked with dissolved silica. During recovery from silica stress, cell division was repressed for 24 h while mean cell silica quota increased 25-fold. The first new scales appeared within 2 h after the silica addition, and development of the new scale layer proceeded in an approximately synchronous manner, residting in normal scale layers on virtually all cells after 48 h of recovery in Sirich medium. Silica content of silica-replete Synura cells is comparable to freshwater diatoms of siynilar size, but Synura has much greater potential quota variability than diatoms and no apparent threshold silica requirement. Silica-limited growth kinetics and competition between diatoms and Synura for silica are discussed. The results suggest that morphological variability of siliceous scales in natural populations of synurophyte flagellates may result from silica stress and that the experimental approach developed here has great potential value as a means for circumscribing ecotypic variation in scale morphology. Results also demonstrate that scale production can be uncoupled from cell division, suggesting that cell cycle regulation of silica biomineralization in the Synurophyceae may be fundamentally different from that of diatoms (algal class Bacillariophyceae). This experimental system has application in the future study of the intracellular membrane systems and the regulatory processes involved in silica biomineralization.  相似文献   

5.
药理学实验中生物医学信号的采集与实验参数的标度变换   总被引:1,自引:1,他引:0  
本文介绍了药理学实验中,实验信号的标定,采样,和实验参数和标度变换等项功能的实现。  相似文献   

6.
7.
福州地区桑白蚧发生动态和药剂防治试验   总被引:1,自引:0,他引:1  
桑白蚧在福州地区一年发生4代.以雌成虫在寄主枝干上越冬.越冬代(第4代)一雌虫产卵量多的达278粒.少的36粒,平均171粒,比第2代产卵量多2.6倍.比第3代多4.5倍.药剂防治试验结果,在2龄幼蚧高峰期,用25%扑虱灵可温性粉剂1500倍液,40%氧化乐果乳油800-1000倍液和95%机油乳剂50—100倍液喷雾.防治效果可达90%左右.用25%扑虱是可湿性粉剂1000-1500倍液.喷酒幼蚕触杀试验和喷洒桑叶喂蚕胃毒试验结果.对幼蚕安全.用扑虱灵防治桑树上的桑白蚧,对养蚕业无不良影响。  相似文献   

8.
The phylogeny of the Synurophyceae was investigated by parsimony analysis of scale case characters and small-sub unit (18S) ribosomal RNA (rRNA) sequence data. Analysis of 1 eustigmatophycean (outgroup), 3 chrysophycean, and 10 synurophycean 18S rRNA sequences corroborated the inference from ultrastructural information that the Synurophyceae is a monophyletic assemblage . Tessellaria vol-vocina, which had been tentatively proposed as a member of the Synurophyceae, was confirmed as the earliest lineage within the Synurophyceae by both the molecular analysis and an evaluation of published ultrastructural data. A second set of analyses investigated the relationships among Tessellaria volvocina, 6 Synura species, and 10 Mallomonas species/varieties, with particular reference to the validity of current classifications of the Synurophyceae and the characters upon which they are based. The molecular and scale case phylogenies were not totally resolved but were largely congruent. The data sets were combined to produce another phylogeny, which showed greater resolution. The combined phylogeny weakly supported our representatives of Synura and Mallomonas as monophyletic groupings and also upheld several of the sections within these genera that are recognized by current classifications. However, some changes to the classification and delineation of these genera are recommended and predicted. Both our 18S rRNA sequence and scale case data sets were more appropriate for examining the branching order among the more closely related text rather than resolving the deeper branching points of the synurophycean phylogeny .  相似文献   

9.
土壤呼吸的影响因素及全球尺度下温度的影响   总被引:188,自引:19,他引:169  
刘绍辉  方精云 《生态学报》1997,17(5):469-476
土壤呼吸是指土壤释放CO2的过程,主要由土壤微生物和根系产生。作为一个复杂的生态学过程,土壤呼吸在受到植被,微生物等生物因素影响的同时,也受到了温度,湿度、pH值等环境因素的作用,并且随着人类影响的增强,人为因素的作用也越来越大。根据已有工作,讨论了影响土壤呼吸的主要影响因素及其相互关系,分析了全球范围内湿润地区森林植被的土壤呼吸与纬度的关系以及土壤呼吸与年均温的关系,得出了全球范围的Q10值为1  相似文献   

10.
Spatial and temporal patterns of gene flow determine the extent to which populations can differentiate from one another as a result of natural selection or genetic drift. In this study, we investigated pollen-mediated gene flow in two eastern Kansas populations of the subdioecious tree species, Gleditsia triacanthos L. (Leguminosae), or honeylocust. In 2 yr at each site, we used paternity-exclusion analysis to estimate the proportion of seeds sired by immigrant pollen. We also used a single-parent and parent-pair exclusion analysis on naturally established seedlings and saplings to estimate gene flow into one site over a 12-yr period and into the second site over a 22-yr period. Results of both analyses showed high minimum estimates of pollen gene flow into each site (17%–30%). In each population, we found significantly less gene flow in years of high fruit production than in years of low fruit production, but in one population, we observed little variation in gene-flow rates among age classes of seedlings and saplings. The level of pollen gene flow showed weak negative dependence on the relative isolation distances of the maternal trees sampled (140–240 m at one site vs. 85–120 m at the second site), and gene-flow estimates from naturally established juveniles were very similar at the two sites. Within populations, a multiple regression model showed that maximum-likelihood estimates of male fertility were negatively associated with distances between mates and positively associated with male size as measured by stem diameter. In neither population, however, did the regression explain more than 16% of the total variation in male fertilities.  相似文献   

11.
The development of scale cells in insects has been studied from the appearance of the first cytoplasmic projection which forms the scale rudiment. This rudiment contains numerous longitudinally oriented microtubules throughout. Immediately under its outer surface lie a series of adjacent but distinct bundles of longitudinally oriented circa 60-A fibrils with a circa 120-A center-to-center spacing. As the rudiment broadens, the microtubules become distributed near the surface. The rudiment finally becomes extremely broad and flattened. Fibril bundles are now widely separated and equally spaced. They still lie immediately below the cell surface. Then the cytoplasm protrudes midway between each fibril bundle to form longitudinal ridges and the major shape changes of the scale have been achieved. The final pattern can thus be related to the cytoplasmic organization of the rudiment. The main cytoplasmic elements which seem important in scale morphogenesis, on the basis of frequency, orientation and grouping, are 60-A fibrils and microtubules.  相似文献   

12.
徐天瑞  刘晨光 《昆虫学报》1997,40(3):283-287
白蜡虫Ericerus Pela的马氏管由两条黄色膨泡串状的端管和一条公共管构成,通过公共管与消化道相连。端管和公共管细胞结构相似,都具有非胶原质的基膜,高度发达的基褶, 长而致密的微绒毛,微绒毛无线粒体插入,细胞质中线粒体少,且随机分布。细胞质的绝大部分为两种矿质-尿酸颗粒结晶所占据,一种为不规则结晶,另一种为轮纹状结晶。白蜡虫马氏管可能发生了合胞化,其排泄方式可能是一种以滞留排泄为主,离子梯度排泄方式为辅的特有的排泄方式。  相似文献   

13.
本文报导一种毫秒级动力学光谱仪。此仪器由微型机Apple Ⅱ来操作和控制。文中报导了软件的设计及其特点。此仪器已用于观察菌紫质(bR)的光循环。  相似文献   

14.
SUMMARY

It is pointed out that due to its construction a tubular system has many advantages, compared to a multiple container system. The most important being the ease of manipulation and the higher yield of algal material. The tubular system has at least a ten fold higher yield per unit time and volume than multiple container systems.  相似文献   

15.
生物驻极体鱼鳞片的NFOM分析   总被引:1,自引:0,他引:1  
利用NFOM系统对生物驻极体鱼鳞片进行了观测,其结果证实了我于鳞片中的骨胶朊的有序排列是其驻极特性的来源;同时又观测到了生物驻极性在生长中的结构的形态分形图像并对之讨论。  相似文献   

16.
Abstract The prey consumption of ovipositing female adults of the ladybeetle Chilocorus kuwanae on the scale Unaspis yanonensis was found to be significantly greater than that of the male adults. At 25°C one female adult ladybeetle, on average, would consume 42. 7 female scale adult per day while one male adult only destroyed 22. 3 female scale adults. However, after a deprivation of the prey for 48 h, this difference was eliminated. A C. kuwanae female adult had to prey on at least 15 U. vanonensis female adults in order to lay eggs. The funcional responses of the beetle adults to densities of different stages of the scale followed Holling's type 1. The functional responses to female scale adults indicated that the maximum prey consumption went up with the increase in temperature from 16°C to 35°C, and dropped sharply at 37°C. However, temperature did not alter the type of the functional response. Rased on the predation of C. kuwanae adults on U. yanonensis female adults, the minimum critical, optimal and maximum critical temperatures for their attack were estimated to be 10. 6°C, 31. 5°C and 38. 2°C respectively. The increase in predation space or in predator density could result in a reduction in the attack rat-e, but with the increase of predator density, the effect of predation space became much smaller. C. kuwanae adults preferred male pupae to other stages of the scale, and their preference for various stages of the prey was in the order of male pupae, 2nd-instar male nymphs, 2nd-instar female nymphs, adult females and kinstar nymphs.  相似文献   

17.
18.
松突圆蚧的化学防治   总被引:17,自引:0,他引:17  
赵善欢  温佛仪 《昆虫学报》1993,36(2):177-184
经过应用10多种化学农药及其与植物油、矿物油的混合制剂进行室内药效筛选、林间地面喷雾试验和两年的飞机防冶试验,我们研制出能有效地防冶松突圆蚧(Hemiberlesia pitysoPhila Takagi)的药剂配方-植物油与矿物油的混合油剂。 这种混合油剂在小区试验巾用5甲。浓度,防治效果可达98.5%;用20%浓度进行飞机喷雾,药量折合5千克/亩,防治效果也达70%以上。这种混合油剂对松突圆蚧的重要天敌红点唇瓢虫(Chilocorus Kuwanae)成虫和丽蚜小蜂( Encasia sp.)安全,对环境一般无不良影响,同时乳化效果好,配制方便,值得开发应用。  相似文献   

19.
Theory indicates that spatial scale and habitat configuration are fundamental for coevolutionary dynamics and how diversity is maintained in host–pathogen interactions. Yet, we lack empirical data to translate the theory to natural host–parasite systems. In this study, we conduct a multiscale cross‐inoculation study using the specialist wild plant pathogen Podosphaera plantaginis on its host plant Plantago lanceolata. We apply the same sampling scheme to a region with highly fragmented (Åland) and continuous (Saaremaa) host populations. Although theory predicts higher parasite virulence in continuous regions, we did not detect differences in traits conferring virulence among the regions. Patterns of adaptation were highly scale dependent. We detected parasite maladaptation among regions, and among populations separated by intermediate distances (6.0–40.0 km) within the fragmented region. In contrast, parasite performance did not vary significantly according to host origin in the continuous landscape. For both regions, differentiation among populations was much larger for genetic variation than for phenotypic variation, indicating balancing selection maintaining phenotypic variation within populations. Our findings illustrate the critical role of spatial scale and habitat configuration in driving host–parasite coevolution. The absence of more aggressive strains in the continuous landscape, in contrast to theoretical predictions, has major implications for long‐term decision making in conservation, agriculture, and public health.  相似文献   

20.
幼草鱼鳞片环纹,以孵出后第二个月生长最快,往后生长减慢,冬季停止生长。幼鱼体长一般在47—70毫米形成幼轮。鳞片的“切割相”是区别年轮和幼轮的标志。幼鱼在饥饿时,环片不仅不增长,反而出现环片被吸收的现象。鳞片上各种副轮标记的形成与摄食条件的变化有关。计算了体长与鳞径、环纹数以及鳞径与环纹数的迴归方程,它们之间都呈直线正相关,相关显著性均在99%以上。    相似文献   

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