104 resultados para ddc: 370


Relevância:

10.00% 10.00%

Publicador:

Resumo:

在野生动物调查工作中, 使用自动感应像机系统虽然已有较长的历史(Dodge 等1960), 但仅在最近其技术进步之后才得到广泛应用(Seydack, 1984; Kucera等,1993). 至此前, 中国未见具体应用的报道. 这种技术对于记录野生动物, 尤其是野生兽类物种的存在和监测是很适合的。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The reproductive traits of Gymnocypris selincuoensis from Selincuo Lake and its tributaries were investigated in 1997 and 1998. The youngest mature male was age 7 with a standard length (SL) of 172.0 mm, and the youngest mature female was age 8 with a SL of 194.0 mm. The L(50)s Of SL and age at first maturity were respectively 250.32 mm and age 9 for males and 224.71 mm and age 8 for females. The gonadosomatic index (GSI) significantly changed with seasons for mature individuals but not for immature individuals. GSIs of mature females at stages IV and V of ovary development increased with SL and reached a maximum value at the SL range from 370 mm to 390 mm; the GSIs of mature males were negatively correlated with SL. The breeding season lasted from early April to early August. Egg size did not significantly change with SL but increased with the delay of spawning. The individual absolute fecundity varied from 1,341 to 28,002 eggs (mean 12,607+/-7,349), and the individual relative fecundity varied from 6.4 to 42.0 eggs.g(-1) (mean 25.5+/-9.7). The individual fecundity increased with total body weight; it also increased with SL for those of SL less than 370 mm. There was a rest of spawning for mature individuals.

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

在综合分析有害水华生物分类鉴定方法研究概况的基础上,阐述了基于光合色素和其它生化标志物的化学分类方法在水华生物检测和鉴定方面的应用,讨论了基于叶绿素a成分分析的监测鉴定技术和基于色素荧光分析的流式细胞技术(FCM)在水华生物化学分类上的优势和特点。相关的分析表明化学分类法能有效地用于对不同属的有害水华生物进行分类鉴定,甚至也能对相同属和种的不同细胞株进行鉴定识别,从而对有害水华生物的鉴定提供较为丰富的分类信息。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

利用全能量收支同步测定呼吸仪系统测定了三种不同蛋白源 (鱼粉、豆粕、土豆蛋白 )饲料对银鲫生长及能量收支各组分的影响。对照饲料全部以鱼粉为蛋白源 ,另两种饲料中3 0 %的蛋白质分别来自豆粕和土豆蛋白。试验结果表明 ,银鲫对三种蛋白源的饲料的摄食率 ,食物转化效率均有显著差异 ,以鱼粉组最高 ,豆粕其次 ,土豆蛋白最低。能量收支各组分也均有显著差异 ,能量收支式如下 :鱼粉  88 1C =1 3 77F +2 95U +2 4 1G +41 8R豆粕  1 0 2 3C =1 7 1F +2 8U +1

Relevância:

10.00% 10.00%

Publicador:

Resumo:

2 0 0 0年 12月在武汉东湖采集了 5个表层沉积物样品 ,采用气 -质联用分析了其中的有机污染物 ,以探讨东湖沉积物受有机物污染的程度 .共检出有机物 180种 ,其中环境优先控制污染物和美国EPA筛选的内分泌干扰物 35种 .有机污染严重程度为 :水果湖区 >郭郑湖南湖区 >郭郑湖北湖区 .

Relevância:

10.00% 10.00%

Publicador:

Resumo:

于 1 996年 4月在中国科学院水生生物研究所关桥实验场取得银鲫E系 ( 8♀ ,2♂ )和D系 ( 9♀ ,1♂ )的卵巢 (♀ )或肝脏 (♂ )组织 ,分离纯化其线粒体DNA ,以此为材料 ,用 2 5种限制性内切酶分析了银鲫这两个雌核发育系的线粒体DNA ,构建了两系鱼mtDNA的 1 9种酶 41个位点的酶切图谱。统计比较酶切片段的大小 ,发现 5种内切酶 (AvaⅡ ,BamHⅠ ,BglⅠ ,SphⅠ ,XbaⅠ )酶切位点在两个雌核发育系间存在差异。这些多态性 ,既可以作为区分两个雌核发

Relevância:

10.00% 10.00%

Publicador:

Resumo:

<正>我国人口众多,淡水资源相对贫乏,随着工业的发展和城市人口迅速增长,含有各种化学品的工业废水和大量未经处理的城市污水纷纷排入江河、湖泊,造成了许多淡水水源的严重污染。水环境质量的恶化,直接影响了居民饮用水质、渔业养殖与农田灌溉。据推测,到21世纪,淡水资源这个人类赖以生存的基本要素,将会更加缺乏,最终必然成为阻碍我国国民经济发展的首要因素。因此,开展水环境保护的研究工作就我国国情来讲,尤其至关重要。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

<正> 瓦氏雅罗鱼(Leuciscus waleckii)是一种适应高寒盐碱化水体生活的主要经济鱼类。用瓦氏雅罗鱼精液和鲮鱼精液混精授精所得的鲮鱼耐寒力有所提高。而对于这类喜冷鱼类细胞培养和染色体核型,迄今国内尚未见报道。为了进一步探讨和利用瓦氏雅罗鱼的耐寒性能,作者先就该鱼的染色体核型进行了分析研究。材料和方法材料取自内蒙古凉城县的岱海。染色体标本的制备采用体外短期培养肾细胞的常规方法。火焰干燥制片,吉姆萨染色法。共分析8个比较清晰的中期分裂相。有关染色体的测量、统计、以

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Photosynthetic activity during rehydration at four temperatures (5, 15, 25, 35 degrees C) was studied in a terrestrial, highly drought-tolerant cyanobacterium, Nostoc flagelliforme. At all the temperatures, the optimum quantum yield F-v/F-m increased rapidly within I It and then increased slowly during the process of rehydration. The increase in F-v/F-m at 25 and 35 degrees C was larger than that at 5 and 15 degrees C. In addition, the changes of initial intensity of fluorescence (F-0) and variable fluorescence (F-v) were more significant at 25 and 35 degrees C than those at 5 and 15 degrees C. Chlorophyll a content increased with the increase of temperature during the course of rehydration, with this being more pronounced at 25 and 35 degrees C. The photosynthetic rates at 25 and 35 degrees C were higher than those at 5 and 15 degrees C. Induction of chlorophyll fluorescence with sustained rewetting at 5 and 15 degrees C had two phases of transformation, whereas at 25 and 35 degrees C it had a third peak kinetic phase and showed typical chlorophyll fluorescence steps on rewetting for 24 h, representing a normal physiological state. A comparison of the chlorophyll fluorescence parameters, chlorophyll a content, and the chlorophyll fluorescence induction led to the conclusion that N. flagelliforme had a more rapid and complete recovery at 25 and 35 degrees C than that at 5 and 15 degrees C, although it could recover its photosynthetic activity at any of the four temperatures. (c) 2007 Published by Elsevier Ltd.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We studied diet composition and overlap of the exotic noodlefish (Neosalanx taihuensis) and the endemic fish Anaborilius grahami in a deep, oligotrophic lake in the Yunnan Plateau. A. grahami dominated the fish community in Lake Fuxian before the invasion of N. taihuensis in 1982, but it is now in the process of extinction, corresponding with an explosive increase in N. taihuensis population. Schoener's index (alpha=0.773) indicate that N. taihuensis and A. grahami have significant diet overlap, with both fish feeding mainly on zooplankton. An increased proportion of littoral prey, such as Procladius spp., Coleoptera, and epiphytes, in the diet of A. grahami indicated that this endemic fish shifted its main habitat from the off-shore zone in the late 1980s to the littoral zone at the present. A difference in reproduction between the two fishes, along with the overfishing, may have exacerbated the occupation of A. grahami's pelagic niche by N. taihuensis. The endemic species has shown large competitive disadvantage for food and space in the presence of N. taihuensis.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Dark respiration (nonphotorespiratory mitochondrial CO2 release) in the light (R-L) of the intertidal macroalga Ulva lactuca (Chorophyta) during emersion was investigated with respect to its response to variations in temperature and desiccation. R-L was estimated by CO2 gas-exchange analysis using the Kok effect method, whereas dark respiration in darkness (R-D) was determined from CO2 release at zero light. Rates of R, were significantly and consistently lower than those of R-D in emersed U. lactuca across all the temperature and desiccation levels measured. This demonstrated that dark respiration was partially depressed in the light, with the percentage inhibition ranging from 32 to 62%. Desiccation exerted a negative effect on R-L and R-D at a high temperature, 33 degrees C, whereas it had much less effect on respiration at low and moderate temperatures, 23 and 28 degrees C. In general, R-L and R-D increased with increasing temperature in U. lactuca during all stages of emersion but responded less positively to temperature change with increasing desiccation. Additionally, the Q(10) value (i.e. the proportional increase of respiration for each 10 degrees C rise in temperature) for R-L calculated over the temperature range of 23 to 33 degrees C was significantly higher than that for R-D in U. lactuca during the initial stages of emersion. Respiratory carbon loss as a percentage of gross photosynthetic carbon gain increased with increasing temperature and/or desiccation but was significantly reduced when estimated using R-L rather than R-D. It is suggested that measurements of R-L and how it changes in a variable environment are as important as estimates of R-D and photosynthesis in determining simultaneous balance between photosynthetic carbon uptake and respiratory carbon loss and in modeling the net daily carbon gain for an intertidal macroalga.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A marine fish cell line from the snout of red spotted grouper Epinephelus akaara, a protogynous hermaphrodite, was established, characterized, and subcultured with more than 60 passages. The grouper snout cell line (GSC) cells multiplied well in Dulbecco's modified Eagle's medium (DMEM) medium supplemented with 10% fetal bovine serum. The optimal growth temperature was 25 degrees C, and morphologically the cells were fibroblastic. Chromosome analysis revealed that the GSC cell line has a normal diploid karyotype with 2n = 8st + 40t. A virus titration study indicated that the cells were susceptible to turbot Scophthalmus Maximus rhabdovirus (SMRV) (10(8.5) TCID50 ml(-1)), while the viral titer of frog Rana grylio virus 9807 (RGV(9807)) reached 10(3.5) TCID50 ml-1. The infection was confirmed by cytopathic effect (CPE), immunofluorescence, and electron microscopy experiments, which detected the viral particles in the cytoplasm of virus-infected cells, respectively. Further, significant fluorescent signals were observed when the GSC cells were transfected with pEGFP vector DNA, indicating their potential utility for transgenic and genetic manipulation studies.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The reproductive traits of Gymnocypris selincuoensis from Selincuo Lake and its tributaries were investigated in 1997 and 1998. The youngest mature male was age 7 with a standard length (SL) of 172.0 mm, and the youngest mature female was age 8 with a SL of 194.0 mm. The L(50)s Of SL and age at first maturity were respectively 250.32 mm and age 9 for males and 224.71 mm and age 8 for females. The gonadosomatic index (GSI) significantly changed with seasons for mature individuals but not for immature individuals. GSIs of mature females at stages IV and V of ovary development increased with SL and reached a maximum value at the SL range from 370 mm to 390 mm; the GSIs of mature males were negatively correlated with SL. The breeding season lasted from early April to early August. Egg size did not significantly change with SL but increased with the delay of spawning. The individual absolute fecundity varied from 1,341 to 28,002 eggs (mean 12,607+/-7,349), and the individual relative fecundity varied from 6.4 to 42.0 eggs.g(-1) (mean 25.5+/-9.7). The individual fecundity increased with total body weight; it also increased with SL for those of SL less than 370 mm. There was a rest of spawning for mature individuals.