Rearing performance of Clarias batrachus larvae: Effect of age at stocking on growth and survival during fingerling production

An experiment was conducted to evaluate the rearing performance of different larval stages for optimum growth and survival during fingerling production of Clarias batrachus with an aim to reduce the rearing time of the catfish larvae in a hatchery system. The larvae were reared for 5, 10 and 15 days before stocking them in the nursery tanks. No significant (P < 0.05) difference could be found in length increment at the end of first week of rearing. But the total length was reduced during rest three weeks in five days old larvae compared to that of other two higher age groups. In 5 days old larvae the reduced weight (P < 0.05) was observed during the entire rearing period. However, the specific growth rate (SGR) did not vary among the groups. The survival rate as well as total biomass was decreased while stocking five days old larvae for rearing, compared to that of other two age groups.     

杂草环境下转EPSPS基因大豆NZL06-698的生态适应性研究

为研究转EPSPS基因大豆NZL06-698在杂草环境中的生态适应性,试验设置杂草处理模拟野外环境,研究转基因大豆NZL06-698(GT698)的生存竞争能力以及外源EPSPS蛋白表达情况。结果表明:在相同处理下转基因大豆GT698的株高(R8期)、百粒重显著高于亲本大豆蒙豆12(MD12),但单株产量、单株籽粒数、结实率显著低于亲本大豆,说明外源基因的存在并未增强转基因大豆的生存竞争力,且转基因大豆在野外的生存竞争能力与亲本大豆相比较弱。试验注意到,杂草环境对转EPSPS基因大豆的生长有明显的限制作用,杂草处理下转基因大豆的单株产量、单株籽粒数、百粒重、结实率等指标均显著低于对照处理。ELISA检测结果表明,转基因大豆叶片及籽粒中外源EPSPS蛋白在杂草处理及对照中均正常表达,且两种处理下的EPSPS蛋白表达量无显著差异。以上结果表明杂草环境中转基因大豆的EPSPS蛋白正常表达,正常提供抗草甘膦性状,但是外源基因的存在并没有增加转基因大豆的生存竞争能力,且转基因大豆的生长受到杂草环境的显著抑制,由此得出结论:与亲本大豆相比,转EPSPS基因大豆NZL06-698在野外环境中生态适应能力较弱。     

甜菜根产量和含糖率性状的QTL定位

为了进行目的基因克隆等进一步的研究,选育高产、高糖、抗病的新品种,由‘JV34-2’和‘2B023’杂交获得F2代群体200株甜菜为材料,利用123个SRAP标记和18个SSR标记,对甜菜的根产量性状和含糖率性状进行QTL定位分析。利用完备区间作图软件QTL icimapping3.1,共检测出根产量和含糖性状的17个QTLs,定位于已构建的遗传图谱的6个连锁群中。根产量性状定位了7个QTLs,LOD值为2.5322~4.0098,可解释变异为4.5704%~12.3782%。含糖率性状定位了10个QTLs,LOD值为2.5385~10.8314,可解释变异为2.3482%~19.3828%。本试验是国内甜菜重要经济性状定位研究中获得QTL定位位点最多的。     

不同豆类对绿豆象发育繁殖的影响

为给综合治理绿豆象提供理论支撑,在室内(28±2℃)条件下,饲养绿豆象,并观察了6种豆类对绿豆象发育和繁殖的影响。结果表明:绿豆象的卵孵化后,幼虫仅在绿豆、红小豆、大豆上可蛀入危害;在绿豆、红小豆和大豆上的世代发育历期分别为26.50、29.90、52.00天;在绿豆、红小豆、大豆上的存活率分别为52.11%、56.45%、1.60%;绿豆象成虫在不同豆种上的产卵历期差异不显著(P0.05);但雌成虫在不同豆种上的产卵量差异显著(P0.05)。综上认为绿豆象的发育和繁殖明显受储粮豆类的影响。     

提高无性系茶苗定植成活率的技术措施

无性系茶苗定植后成活率低,是当前制约无性系茶园建设的主要因素.本文通过大量调查分析,找出了影响无性系茶苗定植成活率的主要因素,探讨了提高无性系茶苗移栽成活率的措施.     

Behavior of four broad-leaved tree species used to revegetate eroded granite hill slopes

Information on primary growth behavior after planting is required for mixed-plantation revegetation using broad-leaved species. To estimate primary growth, especially from the perspective of crown coverage and changing growth rates, we examined the growth and survival of four broad-leaved species that are frequently used in erosion-control plantations in Japan. The species studied were Myrica rubra Sieb. et Zucc., Alnus pendula Matsum., Quercus glauca Thunb., and Q. serrata Thunb. The survival, height, and basal diameter of planted trees were measured over a 4-year period, and crown area was calculated over a 3-year period. We found a negative relationship between relative growth rate (RGR) and survival rate, suggesting that fast growth may be fatal when resources are severely limited. The relative height growth rate (RHGR) of A. pendula was especially high during the early period of the study (1997–1999) and then drastically declined, whereas the opposite tendency was observed in Q. glauca. The results of stem allometry analyses conformed to the specific relationships between height growth and diameter growth of the four species; increases in stem thickness based on height increments were smaller in the pioneer species A. pendula. Between-species differences in coverage per planted tree (mean crown area multiplied by survival rate) were small as a result of the negative relationship between coverage area and survival rate.     

王朗自然保护区岷江冷杉林(Abies faxoniana)更新及其种群结构分析

岷江冷杉(Abies faxoniana)林是四川王朗自然保护区主要群落类型,本文选择典型的亚高山针叶原始林设置标准样地,对其幼苗幼树查数轮生枝、大树钻取树轮样芯确定个体年龄,分别建立苗高-年龄、胸径-年龄的回归方程得到整个种群的年龄结构,通过编制生命表对其进行生存分析.结果表明,岷江冷杉存活曲线属于Deevey-Ⅲ型...     

金帅和嘎啦苹果~(60)Co-γ辐射诱变效应的初步研究

以金帅和嘎啦苹果1年生枝条为试材,采用60Co-γ射线以不同剂量对其进行辐射,结果表明:随着辐射剂量的升高,其嫁接成活率呈下降趋势;金帅和嘎啦的适宜辐照剂量均为40～80 Gy,在此辐射剂量范围内,果树的枝条变短、叶型变窄,二叉枝和多叉枝数量显著增加。     

复方妥曲珠利缓释微囊的药效试验

为了探讨复方妥曲珠利缓释微囊对鸡球虫病的治疗效果及给药方案,确定首次给药剂量和给药频率。在鸡感染柔嫩艾美耳球虫后第3天(粪便变稀)开始给药,于饮水中添加复方妥曲珠利缓释微囊,期间分别以不同频率给予每组鸡药物,各组鸡给药总量相同。以抗球虫指数(ACI)、相对增重率、病变值等指标进行药效学考察研究。试验结果表明,与感染不给药组相比,各给药治疗组ACI均极显著(P<0.01);试验期间给药3次和2次组治疗效果均可达到高效抗球虫效果;发病后2次给药,且首次剂量加倍组抗球虫指数可达188.14,高于其它给药组的ACI(179.03、182.50、175.98),相对增重率达到90.80%,病变值为2.67,治疗效果显著,可作为最佳的推荐给药方案。     

益生菌酪酸菌CB-7的生物学特性研究

[目的]考察酪酸菌CB-7的生物学特性。[方法]对菌株的耐酸、耐胆盐、耐高温性能及其对动物肠道致病菌大肠杆菌、志贺氏菌、沙门氏菌的抑制作用,对肠道有益菌嗜酸乳杆菌、双歧杆菌和粪链球菌生长的促进作用进行了研究。[结果]酪酸菌CB-7在pH值为3.0的培养基中37℃培养4 h后,存活率达90.0%;在含0.3%牛胆盐的培养基中37℃培养4 h后,存活率达到91.8%;经90℃水浴处理10 min、100℃水浴处理5 min后,存活率均在90.0%以上;对大肠杆菌、志贺氏菌、沙门氏菌均有显著的抑制作用,其发酵提取物可显著促进嗜酸乳杆菌、双歧杆菌和粪链球菌的生长。[结论]酪酸菌CB-7具有较强的耐酸、耐胆盐和耐高温性能,对肠道致病菌具有较强的抑制作用,且可显著促进肠道有益菌的生长,因此是一株性能优良的饲用菌株。