中国明对虾2个群体的杂交子一代早期分析

目前,对虾研究主要集中在基础遗传学和遗传改良的潜力研究等方面[1,2].不同的地理群体代表不同的遗传资源,尤其是对虾人工养殖迅速发展的情况下,对不同的群体生长发育性状特点进行评估是非常重要的.遗传改良的目标是提高对虾人工养殖群体的产量,这就需要育种计划不仅要建立在对虾自然群体相关性状差异的研究上,还需要进一步了解不同发育阶段主要经济性状的遗传特性.对虾幼体生长情况和存活率一直都是养殖者和科学工作者关注的问题.已经有研究证明美国大西洋牡蛎和港湾扇贝群体间在幼体生长发育和存活率方面存在遗传差异[3,4].杂种优势在生物界是一个普遍的现象.     

流态化多级速度梯度混凝反应对絮体的保护作用

多级速度梯度的建立理论上可为絮体的成长创造更理想的环境。目前对流化床混凝工艺的研究多是基于单级速度梯度开展的。以粒径为800 μm 和1 200 μm的树脂颗粒为固相,建立多级速度梯度流化床混凝装置,探讨絮体的成长与形态特征。研究结果表明：在单级速度梯度流化床混凝装置中,当以1 200 μm树脂颗粒为固相颗粒、混凝时间为50.3 s时,絮体发生破碎,混凝效率较混凝时间为41.8 s时降低3%;相同初始填充高度的多级速度梯度条件下,絮体尺寸随着混凝时间的延长而逐渐增加,由5.7 μm成长至70.0~75.0 μm,同时混凝效率也较单级速度梯度下提高了5%~10%。絮体之间的碰撞为絮体成长的主要模式。     

辽宁大凌河流域水土保持综合治理效益分析评价

以辽宁大凌河流域为例,对流域水土流失现状、治理成果及综合效益进行分析,重点对工程治理和生物治理措施效益进行评价总结,结果可知:流域水土保持治理工程以耕作、生物、工程三大措施为主,从整体效益来看,工程措施效益最高,而耕作措施的综合效益最小,生物措施居中。一系列水土保持综合项目的大力实施大大降低了土壤流失量,促进了大凌河流域生态环境的良性循环,有效遏制水土流失的发展趋势,将土地利用率提升至58.9%以上,河流域林草覆盖率从最初的16.3%显著提升至58.9%,较治理前土壤侵蚀量明显减少,极大地推动了当地经济发展。     

地震时空丛集的多重分形研究

为探索大地震发生的可预测性,应用分形理论并根据标准数盒子的数值计算方法,研究了华北地区历史地震和唐山地区地震活动的空间分布特征,估算了地震活动能量的分维值并研究了其多重分形谱的几何结构．初步结果显示出大地震发生前,广义维值有明显的下降过程,分形谱ｆ（α）结构有右偏现象．在低于上述时空层次的唐山地区,孕震系统也有类似特征出现．这些异常现象揭示出孕震动力系统的物理机理和激变前的某些不稳定性．     

温度和水流对八斑唇腕水母生长发育的影响

在不同温度和水流条件下,作者分别对八斑唇腕水母(Rathkea octopunctata)伞径、伞高、出芽率和存活时间等生长发育情况展开研究,以期为其人工饲养和科普展示奠定基础。近海9.5℃～14℃采集的八斑唇腕水母暂养1 d后,置于不同水流(静止的1 L烧杯和气泡带动水流的13 L水浴缸)和不同温度(10℃、15℃、20℃和22℃)交叉条件下人工饲养。结果显示, 77 cm/s的水流条件下, 10℃组水母存活时间最长。伞径、伞高与饲养时间呈负相关。温度越高,水母存活时间越短。温度能促进生殖腺快速成熟,但是10℃水母能持续性出芽。水流能保持水母活力,延长存活时间。研究表明,八斑唇腕水母可以通过水螅体横裂生殖和性腺出芽生殖两种方式繁育水母体。因为其个体较小,科技馆可采用低温水浴缸进行培养和长期展示,并对其特殊的出芽生殖方式进行科普讲解。     

长期低温条件对海蜇横裂生殖的影响

采用实验生态学手段,研究了长期低温条件对海蜇螅状体保育存活率和横裂生殖效率的影响.结果表明:海蜇横裂生殖后的螅状体经过1a的长期低温保育后,其存活率约33%,显著高于不采用低温条件保育螅状体的成活率.横裂生殖后的螅状体经长期低温保育后仍具有横裂生殖能力,碟状幼体释放率仍然高达15%,其横裂生殖能力可与正常螅状幼体相比.采用长期低温环境条件,可以有效地提高海蜇螅状体的存活率,并可以恢复促进海蜇的横裂生殖效率,相关结果可以为海蜇苗种生产提供参考和指导.     

Genetic improvement on Chinese shrimp （Fenneropenaeus chinensis）： growth and viability performance in F1 hybrids of different populations

Fenneropenaeus chinensis distributed in the Yellow Sea and Bohai Sea of China and the west coast of the Korean Peninsula. Different geographical populations represent potentially different genetic resources. To learn further the characteristics of different geographical population, crosses among two wild and three farmed populations were produced. The two wild populations were from the Yellow Sea and Bohai Sea (WYP), and the west coast of the Korean Peninsula and coast (WKN). The three farmed populations included the offspring of first generation of wild shrimp from coast in Korea (FKN), the Huang Hai (the Yellow Sea in Chinese) No. 1 (HH 1), and JK98. The phenotypes growth and survival rates of these populations were compared to confirm the feasibility for crossbreeding. The body length (BL), carapace length (CL), carapace width (CW), height of the second and third abdominal segment (HST), width of the second and third abdominal segment (WST), length of the first abdominal segment (LF), length of the last abdominal segment (LL), live body weight (BW), and survival rate were measured. Different combinations were statistically performed with ANOVA and Duncan's Multiple significant difference (P<0.05) in BL, CL, HST, LL, and BW; and insignificant difference (P0.05) in other growth traits and survival rate. The results of Duncan's Multiple Range Test are that BL and CL of was the best combination in all growth traits. Therefore, hybridization can introduce the variation to base populations. The systematic selection program based on additive genetic performance may be more effective than crossbreeding.     

地震时空丛集的多重分形研究

为探索大地震发生的可预测性,应用分形理论并根据标准数盒子的数值计算方法,研究了华北地区历史地震和唐山地区地震活动的空间分布特征,估算了地震活动能量的分维值并研究了其多重分形谱的几何结构．初步结果显示出大地震发生前,广义维值有明显的下降过程,分形谱ｆ（α）结构有右偏现象．在低于上述时空层次的唐山地区,孕震系统也有类似特征出现．这些异常现象揭示出孕震动力系统的物理机理和激变前的某些不稳定性．     

Genetic improvement on Chinese shrimp （Fenneropenaeus chinensis）： growth and viability performance in F1 hybrids of different populations

Fenneropenaeus chinensis distributed in the Yellow Sea and Bohai Sea of China and the west coast of the Korean Peninsula. Different geographical populations represent potentially different genetic resources. To learn further the characteristics of different geographical population, crosses among two wild and three farmed populations were produced. The two wild populations were from the Yellow Sea and Bohai Sea （WYP）, and the west coast of the Korean Peninsula and coast （WKN）. The three farmed populations included the offspring of first generation of wild shrimp from coast in Korea （FKN）, the Huang Hai （the Yellow Sea in Chinese） No.1 （HH1）, and JK98. The phenotypes growth and survival rates of these populations were compared to confirm the feasibility for crossbreeding. The body length （BL）, carapace length （CL）. carapace width （CW）, height of the second and third abdominal segment （HST）, width of the second and third abdominal segment （WST）, length of the first abdominal segment （LF）, length of the last abdominal segment （LL）, live body weight （BW）, and survival rate were measured, Different combinations were statistically performed with ANOVA and Duncan＇s Multiple Range Test. The results show that the survival rate of JK98（♀）×WKN（♂） was the highest, followed by WYP（♀）×WKN（♂）, FKN（♀）×WYP（♂）, FKN（♀）×HHI（♂） and WYP（♀）×FKN（♂）; the body weight of FKN（♀）×HHI（♂） was the highest, followed by FKN（♀）×WYP（♂）, WYP（♀）×WKN（♂）, WYP（♀）×FKN（♂） and JK98（♀）×WKN（♂）; the total length had the same ranking as the body weight. All growth traits in hybrids JK98（♀）×WKN（♂） were the lowest among all combinations. F1 hybrids had significant difference （P〈0.05） in BL, CL, HST, LL, and BW; and insignificant difference （P〉0.05） in other growth traits and survival rate. The results of Duncan＇s Multiple Range Test are that BL and CL of J     

桃花水母的核糖体RNA基因ITS区序列分析及物种鉴定

利用PCR扩增和DNA测序技术,获得了青岛野外采集到的桃花水母(Craspedacusta)核糖体RNA基因ITS区序列。序列比对以及系统进化分析显示,在青岛采集到的桃花水母与索氏桃花水母(Craspedacusta sowerbyi)的ITS区序列相似度最高,同源性在93%以上;同时,在系统发育树中也与索氏桃花水母聚为一支。研究结果表明,青岛采集到的桃花水母为索氏桃花水母,这也是青岛地区桃花水母的新记录。