丁Gui胚胎发育和卵黄囊仔鱼摄食研究

对丁Gui的胚胎发育进行了连续观察，并对其卵黄囊仔鱼在开口摄食之前的发育、生长以及不可逆点作了实验研究。结果表明：（1）丁Gui受精卵在水温21.5℃时，胚胎发育时间约为52h；（2）仔鱼在孵出后第7天开始摄食，初次摄食率第9天达100%，第12天降到50%，进入不可逆点；（3）仔鱼对卵黄囊的日净消耗量的最大值出现在出膜后第1天，体长最大增长率出现的在出膜后的第2天；（4）仔全出膜后第8天，卵黄囊全部吸收，同时，饥饿期仔鱼开始出现负生长。     

东、黄海六种鳗的食性

用饵料生物的生态类群的出现频率百分比组成来划分东、黄海6种鳗的生态属性和食性类型。通过对其食物组成的分析，发现这6种鳗的生态属性均为底层鱼类且分属3种食性类型：前肛鳗、黑尾吻鳗和银色突吻鳗属底栖生物食性；星康吉鳗和食蟹豆齿鳗属底栖生物和游泳动物食性；奇鳗属游泳动物食性。结果还表明：前肛鳗、星康吉鳗和黑尾吻鳗之间不存在食物竞争。同时建议在食性分析中使用食物的能量百分比这一指标，但需要进一步的收集基础数据。     

尼罗罗非鱼摄食器官胚后发育生物学

采用显微解剖，石蜡切片，光镜的扫描电镜观察等方法，系统观测全长６．０－２２３．０ｍｍ尼罗罗非鱼标本２７８尾，描述了口径，鳃耙，口腔上腭，颌齿，咽齿等摄食器官的形态学特点和量性胚后发过程中的变化规律；论述了尼罗罗非鱼的摄方式和摄食机能，摄食器发育与摄食方式的转化，摄食器官数量性状发育与适口食物规格和食物组成的转变，摄食器官发育与饲养生物学技术措施。为制定培育尼罗罗非鱼苗种和饲养食用鱼生物学技术措施提     

播种方式及追肥时期对寒地冬麦旗叶叶绿素荧光参数及产量的影响

在大田条件下,进行了播种方式和追肥时期的运筹对黑龙江冬小麦旗叶叶绿体荧光参数及产量影响的研究。结果表明,适量追肥有利于提高旗叶PSⅡ的潜在活性(Fv/Fo)、光化学的最大效率(Fv/Fm)、实际量子产量和光化学猝灭系数(qP),减小非光化学猝灭系数(qN),从而提高产量。其中,以在垄播条件下返青期追施75kg/hm2尿素+拔节期追施75kg/hm2尿素效果最好。     

螺旋输送装置转速和喂入量对输送性能的影响试验研究

通过试验,研究喂入量和螺旋转速对输送量和功耗的影响。试验结果表明:螺旋转速越高、输送装置的功耗越大,但输送量不随转速无限增大,当转速达到102r/min时输送量达到最大值;喂入量越大,输送量越大,输送装置的功耗也随之增加。因此,在实际应用中能满足生产需求的情况下,转速和喂入量不宜过高。     

当前肉鸭饲养存在的问题及对策

中国是水禽养殖大国。近年来,由于饲养肉鸭成本比快大肉鸡低,经济效益每只1．5～2元,市场消费量越来越大,使中国肉鸭业得到了快速发展,涌现出一大批肉鸭一条龙企业。但由于制种、防疫工程、饲养设施、疾病和饲养管理技术等方面还存在着诸多问题,直接影响了中国肉鸭业的健康发展。该文较为系统地分析了当前存在的问题,介绍了肉种鸭健康养殖的一些饲养管理技术,为中国今后肉鸭业的健康发展提供了参考。     

Growth variation among Bacillus thuringiensis strains can affect screening procedures for supernatant‐secreted toxins against insect pests

BACKGROUND: Supernatant‐secreted proteins in Bacillus thuringiensis (Berliner) (Bt) with insecticidal activity provide an important source of information for discovery of new useful strains and/or entomotoxins. However, physiological variation among isolates might interfere in the detection efficiency of screening procedures on Bt collections. The aim of this study was to assess the magnitude of this variation in a sample of isolates from a tropical Bt collection, which was gauged through the assessment of their temporal patterns of growth and protein secretion in culture supernatants (SNs), as well as of the corresponding toxicity against fall armyworm (Spodoptera frugiperda, JE Smith). Feeding bioassays were performed, with larvae being treated with heated and non‐heated total protein extracted from SNs collected at different culture times. Larva mortality and reduction in pupa formation were observed. RESULTS: Intra‐ and interisolate variations were observed in the temporal patterns of growth, quality and quantity of protein secreted, as well as in insecticidal activity of these SNs, based on larvae mortality and pupation rates. These results suggest that the insecticidal potential of certain isolates can be hidden if comparisons are done on the basis of the same number of cells in the culture and/or the same culturing time. CONCLUSIONS: Methods of screening Bt collections on the basis of feeding bioassays can be misleading with regards to identifying more promising isolates for biocontrol purposes if physiological differences are not considered. The consequences and implications of these findings for the development of experimental systems that depend on toxicity bioassays to identify alternative Bt strains and entomotoxins with practical applicability have been discussed. Copyright © 2011 Society of Chemical Industry     

不同节水种植模式对糜子籽粒产量和水分利用效率的影响

以榆糜2号为材料,研究了长城沿线风沙区不同节水种植模式对糜子籽粒产量及水分利用效率的影响.结果表明,节水种植可以有效地提高农田集水与保墒效果,明显提高土壤水分含量,降低糜子全生育期耗水量与耗水强度,其中,双沟覆膜产量达6 927.43 kg/hm2,比对照增产40.00％,其水分利用效率为17.22 kg/(hm2· ...     

Evaluation of the extinction risk and of conservation alternatives for a very small insular population: the bearded vulture Gypaetus barbatus in Corsica

The bearded vulture Gypaetus barbatus is a large, long-lived osteophagus vulture whose abundance and breeding range have drastically declined during the last century, making it one of the most endangered European bird species. We evaluated the extinction risk of the bearded vulture population in Corsica (a small, isolated breeding population of 8-10 pairs), one of the last extant populations in Western Europe, and estimated its probability of extinction to be 0.165 over the next 50 years. A sensitivity analysis to assess the influence of uncertain demographic rates showed that it is critical to estimate precisely the values of pre-adult survival. Neither the type nor the parameters of density dependence acting on fecundity and survival rates influenced much the extinction risk of the Corsican population. We evaluated the effect of four realistic conservation actions that could be implemented on the Corsican bearded vulture population and rank them in terms of their respective decrease of the current extinction risk faced by this population. We found that the release of two juveniles every other year for 12 years and the increase of fecundity due to selective food provisioning would reduce by more than one-half the current extinction risk of Corsican bearded vulture population. In contrast, even substantial increases in the carrying capacity through large supplemental feeding produced very modest decreases in the extinction risk, thus calling into question the efficacy of one of the main pan-European conservation strategies for this species. Re-establishing a population network within the Mediterranean could be a potentially better strategy, though its efficacy depends on natal dispersal among populations that is currently unknown.     

The use of hand-raised psittacines for reintroduction: a case study of scarlet macaws (Ara macao) in Peru and Costa Rica

This study reports on three scarlet macaw (Ara macao) reintroduction projects using hand-raised birds in Peru and Costa Rica. The habitats at the release sites ranged from pristine tropical forest to forest fragments in an agricultural matrix. The combined first-year survival was 74% and the annual post first-year survival was 96%. Survival rates were very high despite a wide range in predator communities. Number of birds released explained 70% of the variation in survival with birds from larger releases having higher survival rates. Behavioral evidence suggests that birds established at the site facilitated survival of later releases. Breeding attempts were recorded at all three sites and hand-raised birds with wild mates successfully fledged young in Peru. Supplemental feeding post-release played an important role in keeping the birds near the release site and facilitating social interactions. This work shows that properly socialized hand-raised macaws can survive and breed in the wild but that ex-pets are not good release candidates.