首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 265 毫秒
1.
普陀及宁波滩涂弧边招潮蟹生物学特性的研究   总被引:3,自引:0,他引:3  
本文报告了浙江普陀及宁波沿海滩涂弧边招潮蟹生物学特性的研究结果。雄蟹的螯足大小相差悬殊,大螯重占体重的35.89%,大螯重、体重关系式为g=0.4314W-0.7708,体重,甲壳宽关系式为W♀=0.2397d^3.3089,W♂=0.1953d^3.5886。弧边招潮蟹群体主要由甲壳宽为1.8-2.8cm个体组成,占84.48%。洞穴为单洞口型,平均栖息密度为13只/m^2。摄食有机碎屑、底栖硅  相似文献   

2.
本文通过低强度He-Ne激光以能量密度分别为14.31J/cm^2(辐照5’)、28.62J/cm^2(辐照10)、57.24J/cm^2(辐照20)114.52J/cm^2(辐照40)燠夫体外周血后,检测其淋染色畸变率(CA),激光照射血样(能量密度由低到高)未照射血样CA分别平均为4.29‰、3.96‰、3.81‰、3.590‰、4.19‰、X^检测无显著差异,说明低强度的He-Ne激光辐照人  相似文献   

3.
钉螺分布与滩地环境因子的关系   总被引:31,自引:3,他引:28  
长江中下游滩地钉螺的分布与滩地的地下水位关系显著,当地下水位为32cm左右时,钉螺密度和有螺框出现率分别达到其最大值。活螺密度(Y)与地下水位的回归方程为:Y=-1.9686+0.2512X-0.004013X^2;有螺框出现率(Y)与地下水位的关系为:Y=-55.9720+7.5689X=-0.1180X^2;5月份钉螺适宜在土壤含水率30%左右的土壤表层生活。当土壤含水率为28-30%时,滩面  相似文献   

4.
菜心下胚轴原生质体培养和植株再生   总被引:6,自引:0,他引:6  
以萌发3—4 天(长约4 cm )的菜心(Brassica campestris var.parachinesis)无菌苗苍白下胚轴为材料,酶解分离原生质体。经纯化的原生质体,在含0.5 m g/LZT、0.5 m g/L2,4-D、1.0 m g/LNAA 和0.4 m ol/L葡萄糖的K8p 培养基中,进行微滴培养。在起始培养14—18小时,原生质体再生新的细胞壁。36 小时再生细胞开始第一次分裂。第三天分裂细胞频率可达35% 。培养第8—9 天,可见含8—16个细胞的小细胞团,植板率为15% —18% 。3 周后将发育成直径为2 m m 的白色小愈伤组织,转到含0.3 m g/L 2,4-D并用gelrite半固化的培养基上,增殖成4—5 m m 直径的愈伤组织。在MS+ 3.2(或1.6) m g/L BA+ 1.6(或0.8) m g/LZT+ 0.01 m g/L NAA+ 0.1 m g/LGA3 和0.2% 蔗糖的分化培养基上,获得芽的分化。切下约2 cm 长的芽苗,转移到含0.2 m g/LIAA 和2% 蔗糖的培养基上,生根形成完整植株  相似文献   

5.
蓝翡翠每年5月上、中旬迁来,5月下旬开始营巢,穴室呈球状,洞穴深:土坎型59.2±10.53cm;岩崖型52.7±8.59cm。产卵高峰期6月上、中旬,每窝产卵3─5枚,卵椭圆形,卵重12.41g,卵的量度31.32×27.22mm,抱孵性强,孵化期20天,出雏率50.0%。亲鸟共同育雏,育雏期19天。食物种类,有害昆虫占51.5%,河蟹、河虾、河鱼34.1%,青蛙12.1%,蜒3.0%。  相似文献   

6.
精胺和Mg^2+对tRNA^Ile圆二向色谱的影响   总被引:2,自引:0,他引:2  
由于精胺能特异异地刺激哺乳动物tRNA^Ile的氨基酰化,本文用纯化的牛肝tRNA^Ile观察了精胺和Mg^2+对tRNA^IleCD光谱的影响。结果显示:Mg^2+可使牛肝tRNA^IleCD光谱峰向短波方向偏移2nm,波峰为263nm,峰值被增大约10%ΔθMg^2+=2.3×10^3deg.cm^2/dmol;而精胺使牛肝tRNA^IleCD兴谱峰减少40%,Δθspermine=1×10^  相似文献   

7.
研究了闽南绿竹(Dendrocalamopsis oldhami)林硅素的含量特征,库存量及年动态。结果表明:1.绿生林各组分硅素含量有较大差异,分布很不均匀。含量范围为0.208%-6.346%之间,各组分的含量大小顺序是:叶〉细根〉枝〉根茎〉杆;2;绿竹林硅素的现存库存量为261.168g/m^2,其中地上部为20.7385g/m^3,地下部为53.783g/m62,其中地上部为207.385  相似文献   

8.
不同剂量的He—Ne激光对Raji细胞膜脂流动性的影响   总被引:2,自引:0,他引:2  
本文采用荧光偏振法检测了不同剂量的He-Ne激光照射法对Raji细胞膜流动性的影响,发现了0.01J/cm^2和0.51J/cm^2两剂量可使膜脂微粘度降低(P〈0.05)。即其膜脂流动性升高;1.0J/cm^2和2.0J/cm^2的剂量脂微粘度无明显影响,即其膜流动性无明显化(P〉0.05),而6.02J/cm^2的剂量可使膜微粘度明显上升(P〈0.05)。即其膜流动性明显下降。  相似文献   

9.
目的:本文研究低能量氦氖激光照射荷瘤小鼠,观察对荷瘤T淋巴细胞增殖反应的影响。结果:BALB/C雄性小鼠腹腔接种S180接种后,进行激光照射小鼠内眼角,测定正常对照组、肿瘤对照组和7.33、11.00、14.67、22.00J/cm^2和29.33J/cm^2五个剂量激光照射组小鼠的T淋巴细胞增殖反应,结果表明11.00J/cm^2、14.67J/cm^2、22.00J/cm^2剂量的氦氖激光照射  相似文献   

10.
作者在实验室控制温度、湿度等条件下,以麦麸、玉米面粉及鸭跖草为饲料对褐云玛瑙螺进行室内饲养。实验表明:在温度26℃,相对湿度80 ̄90%的条件下,每个成螺平均产卵234.4粒;卵孵化率为90.72%;幼螺成活率为94.3%;从初孵幼螺长至体重为35.6g的成螺需196天/26℃,173天/28℃;从2克重的幼螺长至35.6克重的成螺,每个螺平均累积取食混合饲料229.7g。饲养密度会影响螺的生长,  相似文献   

11.
The egg-laying rate, number of egg masses, number of eggs/mass, number of eggs hatched/snail and egg viability of Biomphalaria glabrata exposed to different doses (5 and 50) of Echinostoma paraensei miracidia were analyzed as indicators of reproductive activity. Polystyrene plates were placed in aquariums containing the snails and every other day for four weeks after infection the plates were removed to count the number of egg masses and eggs laid. After this, the plates were numbered individually and placed in new aquariums free of snails and the egg masses were observed daily to determine the hatching rate. On average there was an increase in the parameters evaluated in the infected snails in relation to the controls (uninfected snails), except for egg viability, which was significantly lower in the groups infected with 50 miracidia. These findings indicate that when infected, this host snail is able to increase its reproductive activity, suggesting an ecological strategy to maintain the species.  相似文献   

12.
For the protozoan species Tetrahymena a series of airplane experiments are reported, which varied gravity as an active laboratory parameter and tested for corresponding changes in geotaxic orientation of single cells. The airplane achieved alternating periods of low (0.01 g) and high (1.8 g; g = 980 cm/s) gravity by flying repeated Keplerian parabolas. The experimental design was undertaken to clearly distinguish gravity from competing aerodynamic and chemical gradients. In this way, each culture served as its own control, with gravity level alone determining the orientational changes. On average, 6.3% of the Tetrahymena oriented vertically in low gravity, while 27% oriented vertically in high-gravity phases. Simplified physical models are explored for describing these cell trajectories as a function of gravity, aerodynamic drag, and lift. The notable effect of gravity on turning behavior is emphasized as the biophysical cause of the observed negative geotaxis in Tetrahymena. A fundamental investigation of the biological gravity receptor (if it exists) and improved modeling for vertical migration in important types of ocean plankton motivate the present research.  相似文献   

13.
The mean haemolymph volume in a copper-tolerant, intermoult (C2-C4) adult (more than a year old) Orconectes virilis, as determined by [14C-carboxylic] inulin dilution method, ranged from 61.17 microliters in females (mean wet body weight = 4.34 g; mean carapace length = 4.43 cm) to 61.79 microliters in males (mean wet weight = 5.73 g; mean carapace length = 4.49 cm). The mean haemolymph volume per cent varied from 14.5 (in females) to 31.1 (in males). Haemolymph from males had an average pH of 7.35, osmotic pressure of 414.1 mmol/kg H2O, and a specific gravity of 1.0603, while that from females averaged a pH of 7.48, osmotic pressure of 433.6 mmol/kg H2O and a specific gravity of 1.0469. Mean total haemocyte counts ranged from 3,434/mm3 (1,000/mm3 halinocytes, 1,125/mm3 hemi-granulocytes and 1,309/mm3 granulocytes) in males to 4,905/mm3 (1,525/mm3 halinocytes. 1,490/mm3 hemi-granulocytes and 1,890/mm3 granulocytes) in females.  相似文献   

14.
The dried peripheral area of pond Idumban (62 ha) increased from 3.2 ha in January to 3 1.9 ha in April. Pila globosa, which were abundant in the littoral area, did not commence aestivation during this period, perhaps due to low temperature and/or high dissolved oxygen content. The number of aestivating snails averaged 0.5/m2 in May, 1973 (3.6% of the total population) and it increased to 1.1/M2 in September (26.2%). Biomass of the snail increased from 3.5 to 19.9 g dry weight (including shell)/M2. Number of aestivating snails increased from 0.4/m2 (5.2% of the total population) in May 1974 to 0.8/m2 (11.1%) in July and the biomass from 4.1 g/m2 to 10.7 g/m2. Availability of dried area for aestivation increased from 5.3 to 23.7 ha in 1973 and from 13.5 to 30.2 ha in 1974.Monthly observations made on the marked snails forced to aestivate at 7.5, 15.0, 22.5 and 30.0 cm depth in the pond during May, revealed that temperature above 35°C and moisture below 5% were critical. Mortality and weight loss decreased in the snails forced to aestivate at increasing depth. Random observations indicated that 83% of the aestivating snails buried themselves at 15 cm depth in the pond. On the whole, 98,480 snails (592 Kg) and 115,270 (758 Kg) died during aestivation in 1973 and 1974 respectively. Of the total weight loss, the energy lost via metabolism contributed only a small fraction of 2.2% (12 Kg) and 2.1% (15 Kg) during these years. Considering the total aestivation area, the snails which succumbed averaged only 0.4/m2/year (2.5 g/m2/year). On an average, dry substance equivalent to about 2.6 mg dry weight/ g dry weight of snail/ day (3.7 gcal/ g live snail/ day) was lost on metabolism by the aestivating snails, i.e. the metabolic level of the aestivating snail was about 1 / 18th of that of the actively feeding snail.  相似文献   

15.
1. The snail Helix aspersa Müller, is negatively geotropic during the daytime, but positive or indifferent at night. 2. The precision of geotropic orientation is a function of the gravity component acting on the body. 3. The rate of geotropic locomotion is also determined by the gravity component (sine of the angle of inclination). 4. The rate of upward movement is increased 1.51 times at 45° inclination by loading the snail with one-half its weight. No such increase is seen in loaded snails creeping on a horizontal surface. 5. Moderate centrifugation results in orientation and locomotion towards the center of rotation. 6. A response analogous to the homostrophic reflex occurs when a backward pull to right or to left is exerted on the shell. Bilaterally equal tension applied to the shell causes locomotion along a path parallel and opposite to the direction of the pull. 7. All the observations go to show that the stimulus for geotropic orientation and locomotion is tension of the body muscles produced by the downward pull of gravity, and that the stimulus is received by the proprioreceptors of these muscles. Otolith apparatus and analogous organs, when present, may assist in the response, but they do not seem to be requisite in all cases. Since the precision of orientation and the rate of locomotion are functions of the gravity component acting on the body, the muscle tension theory of the geotropic reactions accords fully with Loeb''s tropism doctrine for animals.  相似文献   

16.
自然条件下福寿螺繁殖特性   总被引:2,自引:0,他引:2  
为了弄清福寿螺在自然条件下的繁殖特性,在湖南省资兴市水稻田内进行了为期3年的人工养殖试验.结果表明:福寿螺在湘南自然条件下1年可发生不完全3代.第1代、第2代和第3代(越冬代)雌螺的平均性成熟期分别为59.3、45.4和213.0 d.雄螺的平均性成熟期比雌螺早4.3d.福寿螺的自然性比(♀∶♂)为1.54:1.每次交配持续时间平均为19.2h,但并非每次交配后都会产卵.田间福寿螺月产卵块数与月平均气温呈显著正相关(r=0.756).福寿螺卵块的平均孵化期(d)与日平均气温(℃)呈显著负相关(r=-0.980),其线性回归方程为y=-0.726x+23.064.福寿螺卵块的平均孵化期为20.7d,平均孵化率为44.1%.雌螺与雄螺的平均寿命分别为2.40和1.98 a.平均每头雌螺一生可产卵13764粒,可繁殖幼螺6070头.  相似文献   

17.
The objective of the present study was to estimate heritabilities as well as genetic and phenotypic correlations for egg weight, specific gravity, shape index, shell ratio, egg shell strength, egg length, egg width and shell weight in Japanese quail eggs. External egg quality traits were measured on 5864 eggs of 934 female quails from a dam line selected for two generations. Within the Bayesian framework, using Gibbs Sampling algorithm, a multivariate animal model was applied to estimate heritabilities and genetic correlations for external egg quality traits. The heritability estimates for external egg quality traits were moderate to high and ranged from 0.29 to 0.81. The heritability estimates for egg and shell weight of 0.81 and 0.76 were fairly high. The genetic and phenotypic correlations between egg shell strength with specific gravity, shell ratio and shell weight ranging from 0.55 to 0.79 were relatively high. It can be concluded that it is possible to determine egg shell quality using the egg specific gravity values utilizing its high heritability and fairly high positive correlation with most of the egg shell quality traits. As a result, egg specific gravity may be the choice of selection criterion rather than other external egg traits for genetic improvement of egg shell quality in Japanese quails.  相似文献   

18.
A continuing concern of the poultry industry is the high incidence (12%) of egg losses in the laying house due to poor egg shell quality. Calcium (Ca) homeostasis is a key factor in egg shell formation. The economy of Ca utilisation is under the control of Vitamin D(3), particularly its active metabolite 1,25-dihydroxy cholecalciferol [1,25(OH)(2)D(3)]. Supplementation of 1,25(OH)(2)D(3) has been shown to increase specific gravity, shell thickness and shell weight of the egg. However, commercially available synthetic 1,25(OH)(2)D(3) is very expensive. Earlier studies from our Institute [Phytochemistry 37 (1994) 677] have identified a cheap, natural and rich source of 1,25(OH)(2)D(3) in the leaves of Cestrum diurnum (CD), a member of the Solanaceae family. In this study, CD leaves were explored as a source of 1,25(OH)(2)D(3) in the feed of layer birds to improve the egg shell thickness. Fifteen-week-old white leghorn layers were divided into four treatments of 60 birds each and as follows: (I) normal diet with Vitamin D(3), (II) normal diet with Vitamin D(3) + CD, (III) normal diet without Vitamin D(3) and, (IV) normal diet without Vitamin D(3) + CD powder. CD leaf powder was incorporated in to the feed at 0.3% level. The experimental feeding was continued up to 72 weeks of age of the birds. Weekly food intake and daily egg production were noted throughout the experimental period and the specific gravity of the eggs, feed consumed to lay one egg and egg shell thickness were determined. Incorporation of CD leaves in the feed had the maximal effect on all the parameters studied. The feed consumed to lay one egg was 20 g less than the control group. The specific gravity of the egg was higher by 0.005, than the control egg, indicating a 5% decrease in the breakage of eggs in CD fed chicks. Also there was a significant increase (P < 0.001) in egg shell thickness. The data suggest that incorporation of CD leaf powder in the feed of poultry layers increased the egg shell thickness, which in turn could decrease the economic loss due to breakage of eggs.  相似文献   

19.
Carl  Gans  J.-P. Gasc 《Journal of Zoology》1990,220(4):517-536
A series of Ophisaurus apodus was filmed while traversing plane surfaces, fields of nails and pins at different spacings, and channels of different diameter. Small individuals can practise slow lateral undulation on very rough surfaces, but with increased speed, all shift to slide-pushing, using either constrained bends of the body or very wide swings of the tail. In fields of closely-spaced pins, they travel by undulation, often pushing at a limited number of sites and pulling and pushing the trunk among these. Amid pins of wider spacing, the undulation involves some repositioning of curves. In channels, they utilize continuous bend concertina movement with the initial bend formed anteriorly and subsequent ones added, either to the level of the cloaca or on to the tail as well. The cloacal region cannot be established on the basis of locomotor pattern, as the propulsive waves pass smoothly from head to tail. Maximum voluntary velocities (of the centre of gravity) were 13 cm/s for slide-pushing, 55 cm/s for lateral undulation, and 3 cm/s for concertina movement. Propulsion is entirely effected by bending of the trunk; tests gave no evidence that the dorsal and ventral portions of the integumentary armour show significant anteroposterior displacement relative to each other.  相似文献   

20.
Bures S  Weidinger K 《Oecologia》2003,137(4):634-641
Calcium availability may limit the reproductive output of birds and snail shells are considered to be the main source of calcium in many passerine species. This study of collared (Ficedula albicollis) and pied (F. hypoleuca) flycatchers evaluates calcium intake of a natural diet in Central Europe, and sex differences in the utilization of experimentally supplemented sources of calcium during the entire breeding period in aviary birds. The study provides the first evidence that successful reproduction of these species depends on the availability of woodlice (Isopoda) and millipedes (Diplopoda). Each of these two components provided about 3 times more calcium than the snail shells contained in a natural nestling diet. The breeding performance of aviary birds was poor when only snail shells and the fragments of eggshells were provided in food, i.e., irregular laying, smaller clutches, eggshell defects (25 of 53 eggs), and eggs dried-up during incubation. In contrast, no defective eggshell or dried-up eggs were found and the overall breeding performance increased 2–3 times when woodlice were added to the food. Females increased their intake of woodlice during both the pre-laying and laying periods, and both sexes did so during the nestling period. Both sexes took more woodlice in the evening than in the morning, independent of the nesting stage. Intake by females was low until 4 days before laying the first egg, then increased to the highest level, dropping immediately after laying the last egg. Intake of woodlice by both sexes increased steadily from hatching until the nestling age of about 10–12 days decreasing thereafter, which corresponds with the period of rapid skeletal growth. In contrast, the intake of mealworms increased until the nestling age of 13–14 days leveling off thereafter which corresponds with the growth curve of nestling body mass.Due to an error in the citation line, this revised PDF (published in December 2003) deviates from the printed version, and is the correct and authoritative version of the paper.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号