Home range and seasonal movement of taimen,Hucho taimen,in Mongolia     

D. J. Gilroy  O. P. Jensen  B. C. Allen  S. Chandra  B. Ganzorig  Z. Hogan  J. T. Maxted  M. J. Vander Zanden 《Ecology of Freshwater Fish》2010,19(4):545-554

Gilroy DJ, Jensen OP, Allen BC, Chandra S, Ganzorig B, Hogan Z, Maxted JT, Vander Zanden MJ. Home range and seasonal movement of taimen, Hucho taimen, in Mongolia.
Ecology of Freshwater Fish 2010: 19: 545–554. © 2010 John Wiley & Sons A/S Abstract –  Taimen, Hucho taimen, is the world’s largest salmonid and a prized sport fish. We used radio and acoustic telemetry to characterise movements of adult taimen in an extensive river system, the Eg–Uur, in north‐central Mongolia. Forty‐six taimen were tagged with transmitters (27 radio, 17 acoustic and 2 radio‐acoustic combined) and tracked from 2004 to 2008 using mobile surveys and fixed receivers. The mean home range of individual taimen tracked for an average of 2.4 years was 23 km (N = 41, range = 0.5–93.2 km). Of the fish with over 10 relocations (N = 16), 90% remained within a range of 38 km. Four distinct movement patterns were observed: (i) restricted core home range, (ii) core range with seasonal departures, (iii) core range with separate seasonal range and (iv) home range transfer. Movement was greatest in May and June (spawning and postspawning period) with another peak period of movement in September and October (water temperature cooling).  相似文献   

Apical dominance in the shoot and its possible rôle in the survival of Paspalum distichum L.     

A. I. HSIAO  W. Z. HUANG 《Weed Research》1989,29(5):327-334

Summary. When sequential single-node shoot segments (third to fifteenth node, counting from the apex) of the perennial grass weed Paspalum distichum L. were buried in soil, new shoot growth was significantly correlated with initial segment length. Growth from the youngest segment (third), which was about 2 cm long, was only half as great as that from segments 8 to 15, which were initially 2–3·5 times longer. When 14-node shoot segments were buried in soil, the apical bud exerted a dominating influence on shoot emergence and new shoot growth of axillary buds. The degree of suppression increased gradually up to node 8 and then decreased as the distance from the apex increased. A similar result was obtained in these shoot segments following decapitation. However, the degrees and patterns of apical and bud dominance varied in shoots collected during different seasons and also in shoots with different node numbers, node position, cutting and chilling treatments. A possible role of apical and bud dominance in P. distichum in keeping aerial shocks in reserve under adverse conditions, thus providing a survival mechanism for this weed, is discussed.  相似文献   

Outbreak of Arvicola terrestris in rice fields in Yugoslavia1     

Z. DUNDJERSKI 《EPPO Bulletin》1988,18(3):445-451

Macedonia is the southern boundary for the distribution of Arvicola terrestris (water vole) in the Balkan peninsula. Until recently, these voles were found in the region only sporadically, showing none of the cyclic population fluctuations characteristic of microtines in the continental part of Europe. An investigation was started in 1984 when the first visible signs of damage to rice in Ko?ansko Valley, caused by numbers of voles, were noted. Since then, population numbers have increased, reaching a density of 1000 individuals per ha on one locality. The causes of such an unexpected outbreak and the methods for determining role abundance are discussed. The construction of a dam and the extension of rice cultivation have reduced the natural habitats of both vole predators and their competitors. Increased pesticide and fertilizer usage have also affected the fauna unfavourably. Efficient control was attained by means of zinc phosphide baits, specially before the rice growing season (i. e. in winter and early spring).  相似文献   

Ultrastructure of the excretory system of Brachylaimus aequans (Trematoda: Brachylaimoidea)     

T N Soboleva  Z Zdárská  J St?rba  J Valkounová 《Folia parasitologica》1988,35(4):335-339

The ultrastructure of the flame cell, excretory capillaries, ducts, collecting ducts, excretory bladder, and excretory pore of Brachylaimus aequans was studied 6-8 days p.i. The excretory ducts, collecting ducts and excretory bladder are provided with numerous lamellae on the luminal side. The cilia of lateral flames in the excretory ducts have a triated rootlet. The excretory pore is covered by a tegument identical with the body tegument. The syncytium of the excretory bladder is connected with the tegument of the excretory pore by means of a septate desmosome. No lipid or excretory corpuscles have been demonstrated in the excretory system.  相似文献   

Effects of growth stage, leaf position and temperature on adult-plant resistance of wheat infected by Puccinia recondita f.sp. tritici   总被引：2，自引：0，他引：2  

Z. A. PRETORIUS  F. H. J. RIJKENBERG  R. D. WILCOXSON 《Plant pathology》1988,37(1):36-44

Growth stage, leaf position and temperature effects on components of resistance to Puccinia recondita f.sp. tritici in wheat ( Triticum aestivum ) were studied. Inoculation of Era, Glenlea, Sinton and RL6044 plants at five growth stages showed that latent period increased and uredinium numbers decreased as each adult-plant-resistant wheat matured. Growth stage had little effect on latent period in the susceptible cultivar Morocco. No significant differences in latent period determined on the flag, flag -1 and flag -2 leaves of the same plant were observed for Era, Glenlea and RL6044. However, leaf age should be considered in assessing adult-plant resistance because the latent period of P. recondita f.sp. tritici in flag leaves of Sinton was shorter than that determined for the flag-1 and flag -2 leaves. Fewer uredinia developed on the flag -2 leaf of Glenlea than on the flag leaf. The latent period of leaf rust in Era, Glenlea, RL6044 and Morocco was significantly longer at 15°C than at 21°C, but temperature did not affect Sinton to the same degree. Uredinium size was a sensitive criterion of adult-plant resistance. Uredinium development in line RL6044 was significantly restricted at 15°C, but uredinia on Era, Glenlea and Sinton at 15°C were as large as those at 21°C. On the susceptible Morocco uredinia were larger at 15°C than at 21°C.  相似文献   

Two new species of rhipiphoridae (Insecta: Coleoptera) in Israel     

Q. Argaman  Z. Mendel 《Phytoparasitica》1988,16(1):63-63

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Host selection by the pine processionary caterpillarthaumetopoea wilkinsoni     

Z. Mendel 《Phytoparasitica》1988,16(2):101-108

The occurrence of nests of the pine processionary caterpillar (PPC),Thaumetopoea wilkinsoni Tarns (Lepidoptera: Thaumetopoeidae), was recorded in two 9-year-old plots planted withPinus halepensis, P. brutia andP. eldarica in a randomized block design. Nest density was highest inP. eldarica and lowest inP. halepensis. The mean number of nests per tree and their frequency distribution indicate that the preference of the PPC is in the order P.eldarica >P brutia >P. halepensis;it is believed to be related to shape of the tree. Planting ofP. eldarica in camping sites is not recommended, due to its high susceptibility to colonization by the PPC.  相似文献   

对FC株猪源性肠毒素型大肠杆菌致病因子的研究   总被引：1，自引：0，他引：1  

张英  董国雄 《畜牧兽医学报》1990,21(1):67-73

FC菌株是一株从腹泻仔猪粪便中分离的肠毒素型大肠杆菌(Enterotoxigenic E.coli,ETEC)。在MRHA反应中,本菌能凝集人O型、豚鼠、马、绵羊、牛、鸡和兔的红细胞,对人O型和豚鼠红细胞有很高的血凝性,血抗K88和K99血清不能抑制其对豚鼠和绵羊红细胞的血凝。在体外小肠上皮细胞吸附试验中,本菌对仔猪小肠上皮细胞具有强烈的吸附作用;透射电镜和扫描电镜观察证实了FC株菌除表面具有一种纤毛样结构外,还能定居在仔猪小肠段。血清学试验结果表明,本菌的O抗原属于O101。K88和987P两种抗血清均不能凝集本菌,而K99和F41抗血清均可凝集。对纯化的FC株菌粘着素抗原作等电聚焦和聚丙烯酰胺凝胶电泳分析,结果表明,该菌的粘着素是由等电点分别为4.61和9.78,分子量分别为29500和17500的两种蛋白质抗原所组成。此外,用乳鼠胃内投服试验和兔肠结扎试验证明,该菌只产生热稳定肠毒素。总之,本菌是一株能产生ST的K99,F41的肠毒素型大肠杆菌。  相似文献   

Domestic geese (Anser anser L.) as a new host of Cochlosoma anatis Kotlán, 1923     

Z Pecka 《Folia parasitologica》1991,38(1):91-92

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Trifluralin effects on the development of cotton in arid zone soils     

D. DORNAI  Z. GERSTL  Y. CHEN  U. MINGELGRIN 《Weed Research》1991,31(6):375-384

The effect of trifluralin on the growth and development of cotton plants in low-organic-matter soils from the northern Negev of Israel was studied. Trifluralin exhibited linear sorp tion isotherms on these soils, Trifluralin and dinitramine losses from soils under varying moisture regimes and application practices were determined in open systems. The data were fitted to both first-order and biexponential kinetic equations. In about 50% of cases the biexponential kinetic model provided a better fit to the data, but no relationship could be found between the model parameters and environmental or soil properties. Losses were generally greater at field capacity than at 50% field capacity, and at 27°C than at 15°C, and in soils with a lower organic matter content. The trifluralin application rate was negatively correlated with vegetative growth parameters of cotton, but the correlation became weaker with increasing soil organic carbon content. Trifluralin delayed boll production in coarse textured soils, the longest delay occurring at higher application rates. It is concluded that in light soils that contain very little organic matter, trifluralin rates must be maintained at the minimum level required for adequate weed control to prevent damage to crops.  相似文献