华山松腐烂病及防治研究   总被引：1，自引：0，他引：1  

吴兴平  钟兴耀  艾祖明  李世荣  范毅 《西南林学院学报》1999,19(3):182-186

在查清华山松腐烂的病原,首次找到其有性型,在初步掌握病害的侵染循环、危害情况和部分防治试验的基础上,提出了相应的防治措施。  相似文献   

Physiological responses of chickpea genotypes to terminal drought in a Mediterranean-type environment     

L. Leport  N. C. Turner  R. J. French  M. D. Barr  R. Duda  S. L. Davies  D. Tennant  K. H. M. Siddique   《European Journal of Agronomy》1999,11(3-4):279-291

Two field experiments were carried out to investigate the effects of terminal drought on chickpea grown under water-limited conditions in the Mediterranean-climatic region of Western Australia. In the first experiment, five desi (small angular seeds) chickpeas and one kabuli (large round seeds) chickpea were grown in the field with and without irrigation after flowering. In the second experiment, two desi and two kabuli cultivars were grown in the field with either irrigation or under a rainout shelter during pod filling. Leaf water potential (Ψ_l), dry matter partitioning after pod set and yield components were measured in both experiments while growth before pod set, photosynthesis, pod water potential and leaf osmotic adjustment were measured in the first experiment only.

In the first experiment, total dry matter accumulation, water use, both in the pre- and post-podding phases, Ψ_l and photosynthesis did not vary among genotypes. In the rainfed plants, Ψ_l decreased below −3 MPa while photosynthesis decreased to about a tenth of its maximum at the start of seed filling. Osmotic adjustment varied significantly among genotypes. Although flowering commenced from about 100 days after sowing (DAS) in both experiments, pod set was delayed until 130–135 DAS in the first experiment, but started at 107 DAS in the second experiment. Water shortage reduced seed yield by 50 to 80%, due to a reduction in seed number and seed size. Apparent redistribution of stem and leaf dry matter during pod filling varied from 0 to 60% among genotypes, and suggests that this characteristic may be important for a high harvest index and seed yield in chickpea.  相似文献   

Fishing impacts and the degradation or loss of habitat structure   总被引：9，自引：0，他引：9  

S. J. Turner  S. F. Thrush  J. E. Hewitt  V. J. Cummings  & G. Funnell 《Fisheries Management and Ecology》1999,6(5):401-420

The wider effects of fishing on marine ecosystems have become the focus of growing concern among scientists, fisheries managers and the fishing industry. The present review examines the role of habitat structure and habitat heterogeneity in marine ecosystems, and the effects of fishing (i.e. trawling and dredging) on these two components of habitat complexity. Three examples from New Zealand and Australia are considered, where available evidence suggests that fishing has been associated with the degradation or loss of habitat structure through the removal of large epibenthic organisms, with concomitant effects on fish species which occupy these habitats. With ever-increasing demands on fish-stocks and the need for sustainable use of fisheries resources, new approaches to fisheries management are needed. Fisheries management needs to address the sustainability of fish-stocks while minimizing the direct and indirect impacts of fishing on other components of the ecosystem. Two long-term management tools for mitigating degradation or loss of habitat structure while maintaining healthy sustainable fisheries which are increasingly considered by fisheries scientists and managers are: (1) protective habitat management, which involves the designation of protected marine and coastal areas which are afforded some level of protection from fishing; and (2) habitat restoration, whereby important habitat and ecological functions are restored following the loss of habitat and/or resources. Nevertheless, the protection of marine and coastal areas, and habitat restoration should not be seen as solutions replacing conventional management approaches, but need to be components of an integrated programme of coastal zone and fisheries management. A number of recent international fisheries agreements have specifically identified the need to provide for habitat protection and restoration to ensure long-term sustainability of fisheries. The protection and restoration of habitat are also common components of fisheries management programs under national fisheries law and policy.  相似文献   

Estimation of dietary biotin requirement of Japanese seabass,Lateolabrax japonicus C.     

J. LI  L. ZHANG  K. MAI  Q. AI  J. WAN  C. ZHANG  J. ZHANG 《Aquaculture Nutrition》2010,16(3):231-236

A 9‐week feeding experiment was conducted to determine the dietary biotin requirement of Japanese seabass, Lateolabrax japonicus C. Six isonitrogenous and isoenergetic purified diets (Diets 1–6) containing 0, 0.01, 0.049, 0.247, 1.238 and 6.222 mg biotin kg^?1 diet were fed twice daily to triplicate groups (30 fish per group) of fish (initial average weight 2.26 ± 0.03 g) in 18 fibreglass tanks (300 L) filled with 250 L of water in a flow‐through system. Water flow rate through each tank was 2 L min^?1. Water temperature ranged from 25.0 to 28.0 °C, salinity from 28.0 to 29.5 g L^?1, pH from 8.0 to 8.1 and dissolved oxygen content was approximately 7 mg L^?1 during the experiment. After the feeding experiment, fish fed Diet 1 developed severe biotin deficiency syndromes characterized by anorexia, poor growth, dark skin colour, atrophy and high mortality. Significant lower survival (73.3%) was observed in the treatment of deficient biotin. The final weight and weight gain of fish significantly increased with increasing dietary biotin up to 0.049 mg kg^?1 diet (P < 0.05), and then slightly decreased. Both feed efficiency ratio and protein efficiency ratio showed a very similar change pattern to that of weight gain. Dietary treatments did not significantly affect carcass crude protein, crude lipid, moisture and ash content. However, liver biotin concentration (0–6.1 μg g^?1) significantly increased with the supplementation of dietary biotin (P < 0.05), and no tissue saturation was found within the supplementation scope of biotin. Broken‐line regression analysis of weight gain showed that juvenile Japanese seabass require a minimum of 0.046 mg kg^?1 biotin for maximal growth.  相似文献   

Interactive effects of dietary cholesterol and protein sources on growth performance and cholesterol metabolism of Japanese flounder (Paralichthys olivaceus)   总被引：1，自引：0，他引：1  

J. DENG  K. MAI  Q. AI  W. ZHANG  X. WANG  B. TAN  W. XU  Z. LIUFU  H. MA 《Aquaculture Nutrition》2010,16(4):419-429

A feeding trial was conducted to compare the effects of supplemental cholesterol in fish meal (FM), fish protein concentrate (FPC), soy protein isolate (SPI) and soy protein concentrate (SPC)‐based diets on growth performance and plasma lipoprotein levels of Japanese flounder (Paralichthys olivaceus). Eight isonitrogenous and isocaloric diets including FM, FPC, SPI or SPC as sole protein source with or without supplementation with 10 g cholesterol kg^?1 diet were fed to juvenile fish for 8 weeks. Dietary cholesterol supplementation significantly increased the feed intake and specific growth rate in fish fed SPI‐based diets, but decreased those in fish fed FPC‐based diets. In addition, cholesterol supplementation significantly increased the level of cholesterol and ratio of low‐density lipoprotein cholesterol to high‐density lipoprotein cholesterol in plasma of fish fed fish protein‐based diets, whereas no effects were observed in fish fed soy protein‐based diets. The hepatic lipid content of fish fed FPC‐, SPI‐ or SPC‐based diets were significantly increased by supplemental cholesterol, but no influence was observed in fish fed FM‐based diets. These results suggested that dietary protein source modify the growth‐stimulating action of cholesterol; cholesterol supplementation may increase the arteriosclerotic lesion in fish fed fish protein‐based diets and the incidence of fatty liver in fish fed soy protein‐based diets.  相似文献   

Influence of 18:2n‐6/20:5n‐3 ratio in diets on growth and fatty acid composition of juvenile abalone,Haliotis discus hannai Ino     

W. XU  K.S. MAI  Q.H. AI  B.P. TAN  W.B. ZHANG  H.M. MA  Z.G. LIUFU 《Aquaculture Nutrition》2011,17(3):346-351

A 120‐day feeding trial was conducted to examine the effects of the ratio of dietary linoleic acid (LA, 18:2n‐6) to eicosapentaenoic acid (EPA, 20:5n‐3) on the growth and fatty acid composition of juvenile Haliotis discus hannai (initial shell length 10.23 ± 1.48 mm; initial body weight 0.13 ± 0.05 g) in a recirculation water system. Five semipurified diets with 35 g kg^?1 total lipid were formulated to contain graded LA/EPA ratios (1 : 0, 0.75 : 0.25, 0.5 : 0.5, 0.25 : 0.75, and 0 : 1, respectively). Twenty‐five juveniles were stocked in a rearing unit, a plastic basket (20 × 20 × 10 cm), as a replicate, and there were three replicates for each dietary treatment. The results showed that abalone survival rates were generally high (90.1–98.3%) and independent of the dietary treatments. However, abalone growth was significantly affected by LA/EPA ratio (P < 0.05). The LA/EPA ratio of 0.25 : 0.75 (Diet 4) produced the highest weight gain rate (WGR, 416.3%), closely followed by the ratio of 0 : 1 (Diet 5, 412.9%), the ratio of 0.5 : 0.5 (Diet 3, 399.7%) and the ratio of 0.75 : 0.25 (Diet 2, 372.1%), but no significant differences were observed among these treatments. The abalone fed the diet without 20:5n‐3 (Diet 1) had the lowest WGR (Diet 1, 363.8%), which was significantly lower than that of Diet 4. Fatty acid profiles in abalone body reflected those of dietary lipids, especially for the polyunsaturated fatty acids. The contents of arachidonic acid (AA; 20:4n‐6) in abalone tissues were positively correlated with dietary level of 18:2n‐6 (P < 0.05). Similar correlation was also observed between the level of docosahexaenoic acid (DHA, 22:6n‐3) in abalone tissues and the level of dietary EPA. It is suggested that abalone, H. discus hannai, have the capacity to synthesize 20:4n‐6 from 18:2n‐6, and maybe 22:6n‐3 from 20:5n‐3.  相似文献   

强力霉素壳聚糖纳米粒冻干粉的制备及其稳定性研究     

沈丹怡  丁运敏  艾晓辉  刘永涛  余少梅  索纹纹 《淡水渔业》2011,41(3):55-60

采用离子交联法和冷冻干燥法制备强力霉素壳聚糖纳米粒冻干粉,并以包封率为评价指标,正交试验优化处方与工艺,用透射电镜观测其形态,纳米粒度及电位分析仪测定其粒径大小、分布和电位,并考察其热、光和高湿稳定性.结果显示,按壳聚糖浓度为2.5 mg/mL、三聚磷酸钠浓度为1.2 mg/mL、强力霉素用量为8.0mg、pH值为5....  相似文献   

盐度和胁迫时间对九孔鲍α-淀粉酶基因表达量的联合效应分析     

钱佳慧  栗志民  刘建勇  艾加林 《中国水产科学》2017,24(1):57-64

采用中心复合设计和响应曲面法研究了盐度和胁迫时间对九孔鲍(Haliotis diversicolor supertexta)?-淀粉酶基因表达量影响的联合效应,旨在为九孔鲍盐度驯化及海区推广提供指导。实验设定盐度范围为22~40,时间范围为0~72 h,建立了盐度、胁迫时间与?-淀粉酶基因表达量之间关系的定量模型,并通过分析明确了盐度和胁迫时间的最优组合。结果表明,盐度对九孔鲍?-淀粉酶基因表达量影响的一次效应不显著(P0.05),而二次效应极显著(P0.01),说明盐度与九孔鲍?-淀粉酶基因表达量之间为非线性关系。随盐度升高,淀粉酶基因表达量呈先上升后下降的变化趋势,当盐度为31时淀粉酶基因表达量最大,此时九孔鲍消化能力最强。胁迫时间对淀粉酶基因表达量影响的一次效应显著(P0.05),二次效应不显著(P0.05),表明胁迫时间与九孔鲍?-淀粉酶基因表达量之间呈线性关系,即随着胁迫时间的延长,淀粉酶基因从开始低水平表达逐渐升高并恢复至正常表达水平。盐度和胁迫时间之间不存在交互作用。对实验结果建立模型可知,?-淀粉酶基因表达回归模型达极显著水平(P0.05),且失拟项不显著(P0.05),表明实验拟合出的方程有效。回归方程的决定系数为80.05%,校正系数65.80%,预测系数50.18%,表明方程拟合度较好,模型选择较为恰当,可以为不同盐度和胁迫时间诱导下的淀粉酶基因表达量变化提供参考依据。  相似文献   

Turf wars: The livelihood and mobility frictions of motorbike taxi drivers on Hanoi's streets     

Binh N. Nguyen  Sarah Turner 《Asia Pacific viewpoint》2023,64(2):171-187

In Vietnam's capital city Hanoi, the growing popularity of application based (app-based) motorbike taxis has offered many inhabitants new opportunities to pursue a mobile livelihood with ride-hailing platforms. Nonetheless, as this influx of app-based drivers has hit the city's streets, specific livelihood and mobility frictions have emerged, notably with informal, ‘traditional’ motorbike taxi drivers, or xe ôm. In this paper we analyse these evolving sites and moments of friction and their impacts on driver livelihoods and mobilities for both driver groups. We draw conceptually on debates regarding mobility, platform economies, and urban livelihoods, while specifically interrogating the concept of friction to highlight three possible analytical applications. Methodologically, we interpret static and ride-along interviews completed with over 130 drivers. We highlight a range of tactics ‘traditional’ and app-based motorbike taxi drivers have employed to respond to rising frictions, defend their ‘turf’, and maintain their street-based livelihoods. Driver responses reveal differing access to distinctive forms of social capital and social networks, and contrasting levels of agency regarding their mobilities. By conceptually teasing apart the notion of friction, we wish to expand and deepen understandings of the experiences of vulnerability, precarity, and other impacts of platformisation for different motorbike taxi driver cohorts.  相似文献   

鱼类细胞培养技术研究进展   总被引：1，自引：0，他引：1       下载免费PDF全文

艾庆辉  李庆飞  麦康森 《渔业科学进展》2012,33(3):122-128

鱼类细胞培养技术是一种重要且有潜力的生物学研究技术手段和方法。随着生物技术的发展,越来越多的鱼类细胞系(株)被建立。鱼类细胞培养的具体方法因细胞种类而异,但是总体上有共同之处。作者针对鱼类细胞培养的发展现状、应用与特点、方法技术进行综述,并为鱼类细胞培养的发展前景作出展望。  相似文献