水温和盐度对大菱鲆稚鱼存活的影响   总被引：5，自引：0，他引：5  

木云雷  宋广军 《水产科学》2005,24(12):1-3

采用突然改变温度和盐度的方法,试验不同水温和盐度对大菱鲆稚鱼存活的影响。试验结果表明,水温为15.0~18.0℃、盐度为28~32,大菱鲆稚鱼存活率最高;用曲线回归的方法求出24 h内存活率与温度的关系式,其回归方程为y=-0.5506x2 18.4970x-53.13,依此得到大菱鲆稚鱼的高、低起始致死温度为26.54℃和7.06℃。依同样方法得到24h内存活率与盐度的回归方程为y=-0.4353x2 23.4226x-213.81,高、低起始致死盐度为37.76和16.05。经t检验显著相关(P<0.01)。  相似文献   

Reproductive performance,survival and development of nauplii and copepodites,sex ratio and adult life expectancy of the harpacticoid copepod,Euterpina acutifrons,fed different microalgal diets     

Thomas Camus  Chaoshu Zeng 《Aquaculture Research》2012,43(8):1159-1169

A series of laboratory experiments were conducted on the harpacticoid copepod, Euterpina acutifrons, to assess the influence of 10 different microalgal diets (four monoalgal and six mixed algal diets) on several parameters related to its productivity in culture. The four monoalgal diets were the Tahitian strain of Isochrysis sp. (T‐Iso), Pavlova salina (Pav), Tetraselmis chuii (Tet) and the diatom Chaetoceros muelleri (Chaet), the five binary diets were T‐Iso+Tet, Pav+Tet, T‐Iso+Pav, Tet+Chaet and Pav+Chaet, while the tri‐algal diet was T‐Iso+Tet+Pav. All diets were fed to copepods at 1500 μ gC L^?1 and in the case of binary or trialgal diets, carbon concentration was divided equally between the two or three algae offered. Among monoalgal diets, the diatom Chaet was excellent for E. acutifrons. Out of the 10 diets tested, the binary diet Tet+Chaet, which contained the diatom Chaet, was the best for naupliar production of single pair E. acutifrons (19.5±1.7 nauplii female^?1 day^?1), significantly (P<0.05) higher than all other treatments except for the Chaet treatment (P>0.05). Similarly, in the group naupliar production trial (50 adult E. acutifrons per replicate), Tet+Chaet produced a significantly higher number of nauplii (405.8±18.6 nauplii day^?1) than the other treatments (P<0.05). Tet+Chaet further supported the highest naupliar survival (82.0±2.8%) and copepodite survival (89.0±2.8%), while the mono‐algal diet Chaet produced the second highest naupliar (76.7±2.6%) and copepodite survival (83.5±2.6%). In contrast, Pav produced the lowest overall survival at the naupliar stage (30.0±2.9%), significantly lower than all other treatments (P<0.05). While development from newly hatched nauplii to copepodites was not significantly affected by diets, mean development time from nauplius to adult was significantly different among treatments. Mean development time from hatching (naupliar I stage; NI) to the adult stage was the fastest with Tet+Chaet and Chaet (6.8±0.0 days for both treatments), which was significantly faster than that of Pav, T‐Iso Pav+Tet and T‐Iso+Pav+Te treatment (P<0.05). E. acutifrons sex ratio was significantly affected by diets, and always skewed in favour of males. Feeding on Pav resulted in the lowest proportion of females (23.7±1.2%), significantly lower than for six of the other treatments (P<0.05). Adult females had longer average life expectancy than males for all treatments, and were the longest when fed Tet+Chaet (9.5±0.4 days), which was more than twice as long as the shortest lifespan recorded for the Pav treatment (4.2±0.6 days) (P<0.05). In summary, among 10 diets tested, the binary diet Tet+Chaet appeared to support the highest culture productivity of E. acutifrons while the diatom Chaet also performed well as a monoalgal diet.  相似文献   

Genetic parameters for growth‐related traits and survival with age in the Kuruma shrimp Marsupenaeus japonicus     

Jiahui Liu  Jingjing Zheng  Jianyong Liu 《Aquaculture Research》2019,50(1):42-48

Genetic parameters were estimated for growth‐related traits and survival of the Kuruma shrimp Marsupenaeus japonicus based on 66 families, including 30 paternal half‐sib families, which were obtained using artificial insemination of two females by each male. The variance components for growth‐related trait and survival were estimated using a single‐trait animal model and a sir‐dam model, respectively, and genetic parameters were estimated using the restricted maximum likelihood method. The coefficients of variation for growth‐related traits such as body length (BL), abdominal length (AL), and body weight (BW) were 9.36%–22.44%, 10.61%–21.92%, and 26.47%–58.33%, respectively, at different ages (45, 75, 105, 135, and 165 days). The corresponding heritability estimates for each growth trait were 0.1545–0.1951, 0.1672–0.1905, and 0.1596–0.1934, respectively, all of which were found to be at moderate levels and increased with age. The heritability of survival on day 165 was low (0.003). The genetic correlations among growth traits were positive and high (0.7316–0.9896) at the different ages, suggesting that selection to improve any single growth trait will cause positive responses in other growth traits examined in M. japonicus. The genetic correlations between growth traits and survival were also positive but low (0.005–0.087), which indicated that only selecting for growth traits may not cause a positive correlated response in the survival of the core population. According to the above results, we suggested that growth and survival traits should be taken as improving targets of breeding in M. japonicus. These results provided reference data for selective breeding and multitrait selection of M. japonicus.  相似文献   

Kojic acid inhibited melanin synthesis by tyrosinase pathway in Pteria penguin     

Feifei Yu  Xiaoyu Tang  Bingliang Qu  Zhiming Zhong  Wanyu Zhang  Xiangyong Yu 《Aquaculture Research》2020,51(4):1584-1591

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Influence of river conditions during seaward migration and ocean conditions on survival rates of Snake River Chinook salmon and steelhead     

C. E. Petrosky  H. A. Schaller 《Ecology of Freshwater Fish》2010,19(4):520-536

Petrosky CE, Schaller HA. Influence of river conditions during seaward migration and ocean conditions on survival rates of Snake River Chinook salmon and steelhead.
Ecology of Freshwater Fish 2010: 19: 520–536. © 2010 John Wiley & Sons A/S Abstract – Improved understanding of the relative influence of ocean and freshwater factors on survival of at‐risk anadromous fish populations is critical to success of conservation and recovery efforts. Abundance and smolt to adult survival rates of Snake River Chinook salmon and steelhead decreased dramatically coincident with construction of hydropower dams in the 1970s. However, separating the influence of ocean and freshwater conditions is difficult because of possible confounding factors. We used long time‐series of smolt to adult survival rates for Chinook salmon and steelhead to estimate first year ocean survival rates. We constructed multiple regression models that explained the survival rate patterns using environmental indices for ocean conditions and in‐river conditions experienced during seaward migration. Survival rates during the smolt to adult and first year ocean life stages for both species were associated with both ocean and river conditions. Best‐fit, simplest models indicate that lower survival rates for Chinook salmon are associated with warmer ocean conditions, reduced upwelling in the spring, and with slower river velocity during the smolt migration or multiple passages through powerhouses at dams. Similarly, lower survival rates for steelhead are associated with warmer ocean conditions, reduced upwelling in the spring, and with slower river velocity and warmer river temperatures. Given projections for warming ocean conditions, a precautionary management approach should focus on improving in‐river migration conditions by increasing water velocity, relying on increased spill, or other actions that reduce delay of smolts through the river corridor during their seaward migration.  相似文献   

小花忍冬硬枝扦插影响因素分析     

赵丽  季蒙  王美珍  乔福成 《内蒙古林业科技》2011,37(4):38-40,43

小花忍冬是观赏性和抗逆性兼具的优良树种之一。为了解决其种子繁殖子代分化变异大的问题,结合小花忍冬特性,通过不同基质、激素及不同浓度的处理,对其进行了硬枝扦插试验。结果表明：基质种类、激素种类、激素浓度都直接影响其扦插成活率,激素种类直接影响地下根系的生长量。其中,使用珍珠岩︰沙子=1︰2、NAA、100 mg/L组合,...  相似文献   

红花山玉兰组织培养外植体的选择及其消毒方法   总被引：2，自引：0，他引：2  

唐军荣  高柱  刘腾云  赵晓洁  李伟 《贵州农业科学》2014,(11)

为筛选出红花山玉兰组织培养适宜的外植体类型及其消毒方法，为红花山玉兰的无性繁殖提供技术支持，对灭菌时间、外植体类型和取材时间等进行研究。结果表明：茎段和顶芽的存活率分别为40．0％和33．33％，较叶片和叶柄的存活率高，且茎段和顶芽的存活率较叶片的存在显著差异，二者的死亡率均与叶柄和叶片的存在显著差异；茎段和顶芽为适宜的外植体。茎段在6月取材优于12月，且采用0．1％的升汞消毒10 min，其存活率为40．0％；顶芽在6月和12月取材均可，消毒后去除托叶能够有效地降低顶芽的污染率，提高其存活率。最佳消毒组合：先用75％的酒精表面喷洒预处理，再用0．1％的升汞消毒10 min，之后去除顶芽的托叶。该方法污染率和死亡率低，存活率最高，依次分别为6．67％、7．78％和85．55％，且芽启动率高。  相似文献   

转基因奶牛胚胎移植技术的试验研究   总被引：2，自引：1，他引：1  

薛建华  周高峰  赵鹏  吴胜权  朱玉林  李艳华  戴蕴平  李荣 《中国奶牛》2010,(9):23-26

2006年6月至2010年3月以来,北京奶牛中心与中国农业大学合作,在北京奶牛中心良种场开展了转基因牛胚胎移植试验研究。本试验利用中国农业大学培育的转基因母牛作为供体,进行超数排卵生产体内胚胎,将获得的胚胎移植给15～15.5月龄荷斯坦母牛受体。截止2010年3月21日,累计移植转基因奶牛胚胎87枚,移植受体牛87头,妊娠48头,移植妊娠率为55.17%;产犊43头,成活34头,犊牛成活率为79%;经中国农业大学研究人员检测,有14头公牛携带转入目的基因,这14头公牛已全部进入北京市种公牛站饲养。目前,有10头公牛到了试采精月龄,精液经农业部牛冷冻精液质量监督检验测试中心(北京)检测,质量符合国家标准。  相似文献   

探讨如何提高大树移植的成活率     

杜炜怿 《北京农业》2012,(6):170

据各大城市提供的数据分析,大树移植的成活率仅在50%左右,这个问题日益受到有关专家及园林建设者们的重视。如何提高大树移植的成活率?笔者经过多年的实践,认为,大树移植是一项系统的工程,需要严格的技术要求和具体的养护措施,只有遵循自然生长规律,才能收到较好的成活效果。  相似文献   

花生组培苗嫁接技术的研究   总被引：5，自引：0，他引：5  

郝世俊  隋炯明  乔利仙  王晓杰  王晶珊 《青岛农业大学学报(自然科学版)》2010,27(2):110-113

为解决花生组培再生苗及转基因苗驯化移栽成活率低的难题,本试验以花生实生苗作为砧木,对花生嫁接技术进行了研究。试验结果表明:超净台内无菌嫁接效果较好,以再生苗或实生苗为接穗进行无菌嫁接,其成活率均达90%以上,明显高于室内嫁接成活率(71%～72%);无菌嫁接时12～15d苗龄的砧木效果最好;将无菌嫁接苗在培养基中培养3～5d后进行驯化移栽为最佳时期;不同花生基因型嫁接苗成活率在87%～95%;嫁接苗移栽田间后,其成活率高达94%,且100%结果。  相似文献