人工养殖湖泊花(鱼骨)卵巢周年变化与性成熟年龄的研究

对花(鱼骨)作组织学研究表明,人工养殖湖泊中花(鱼骨)的卵巢发育可划分为六期,花(鱼骨)的性成熟年龄为一冬龄。     

基于被动声学技术的海洋生物测量研究进展

综述了开展基于被动声学技术实现海洋生物测量的重要性;介绍了国内外被动声学技术用于海洋鱼类测量的研究背景、发展现状、存在的问题和发展趋势。列举了常用的被动测量设备以及被动声学数字信号处理方法,包括数据采集、预处理、端点检测、特征提取和识别技术;分析了采用上述测量技术可以研究海洋鱼类的栖息地、生活习性以及人类活动对鱼类的影响。通过列举石首鱼和鳕鱼的发声研究,提出今后被动声学技术研究的重点应集中于各种被动鱼目标特征库的建立和完善,鱼类、海豚等海洋生物的被动声辐射机理的分析,具有代表性的声特征参数以及鱼类发声和特殊行为之间的关联的研究。     

圆斑星鲽染色体与多种显带的形态特征分析

采用体内注射植物血细胞凝集素(PHA)和秋水仙素法制备圆斑星鲽染色体,研究其染色体C-带、Ag-NORs带及G-带的显带特征.结果发现,圆斑星鲽具有46条染色体,核型为2n =46t,染色体臂数为NF =46,所检个体全部为二倍体,未发现存在异型性染色体和随体染色体的现象.带型研究表明,C-带特征为46条染色体均有大小不一的C-带,其中第22对染色体整体呈阳性深染,第19对染色体具有端部C-带,其余均为着丝粒C-带;计算其异染色质含量为30％;Ag-NORs带型特征为具有1对Ag-NORs,位于2号染色体的长臂末端,为端部Ag-NORs; G-带特征为具有38条深染带,21条浅染带.研究结果为圆斑星鲽染色体组学和种质资源保护提供了基础资料.     

东海银鲳卵巢周年变化的组织学观察

本文对东海银鲳的卵巢周年变化、卵母细胞发育等作了研究。结果表明,东海银鲳的繁殖期在5—6月。繁殖期过后,其卵巢发育长期处在重复发育的Ⅱ′期,并在此期过冬,至翌年3月下旬卵巢再次发育。在卵母细胞发育早期,胞质内便出现油球结构,胞质有分层现象。卵母细胞发育至大生长期晚期后,其放射带减薄且渐消失。待卵母细胞充分发育时,仅存单层的胶质膜结构。银鲳为短期分批产卵类型。     

香鱼卵巢发育的组织学研究

本文根据在天然水域中各个不同发育阶段香鱼卵巢的组织学观察资料，对香鱼卵膜结构、第2时相卵母细胞中出现的透明层、核仁排出物在卵黄形成中的作用以及受精孔形态等问题作了描述和探讨．并对香鱼性周期内卵巢发育和产卵类型等问题作了说明．     

正烷酵母饲养鲤鱼的试验

本试验以高剂量和全剂量的正烷酵母，对鲤鱼作了亚急性的毒性试验，结果表明对增长具有鱼粉般的效果；试验鱼的血液有形成份。血液化学指标均正常；肌肉残毒量低于允许值；组织检查末发现异状或病变；繁殖力和后代的生长均较正常。     

Effects of low dietary protein level on serum oestradiol,testosterone and sex reversal in rice field eel,Monopterus albus (Zuiew)

We investigated the effects of low dietary protein in isocaloric diets on sex reversal of Monopterus albus by evaluating the oestradiol (E₂) and testosterone (T) concentrations, gonadosomatic index (GSI), sex ratio and gonad structure at the histological level. Fish (9.50 ± 1.50 g average initial weight; n=3 per group) were fed with five practical diets containing 100, 150, 200, 250 or 400 g kg^?1 crude protein to apparent satiation for 15 months. Serum E₂ and T concentrations were determined by radioimmunoassays. E₂ concentrations and GSI significantly increased while T concentrations decreased as the dietary protein level was raised. Fish fed 400 g kg^?1 of dietary protein had significantly higher E₂ concentrations and GSI than those fed with lower dietary protein levels. The T concentrations of fish fed 100 g kg^?1 of dietary protein was significantly higher than that of fish fed higher dietary protein levels. The shift of sex ratio towards more male and intersex fish was observed with decreasing dietary protein levels. Therefore, low dietary protein level may promote sex change from female to male in M. albus. This study provides important information for successful reproductive management and may be exploited for aquaculture of this species.     

A dietary modification approach to improve the osmoregulatory capacity of Litopenaeus vannamei cultured in the Arizona desert

A modified diet was formulated for Arizona inland shrimp farming and tested as a method for reducing moult‐associated mortalities presumed due to trace mineral deficiencies. The experimental diet was supplemented with additional dietary magnesium, potassium, phospholipids and cholesterol to a commercial shrimp feed (Rangen 45/10, which was also used as the control diet). The modified diet was tested at Arizona Mariculture Associates (AMA), while the control diet was used at a nearby inland shrimp farm, Desert Sweet Shrimp Farm (DSSF). Both feeds were used throughout the culture season of 2001. Earthen pond‐reared Litopenaeus vannamei at intermoult stages (C‐D₀) and ranging from 7 to 30 g were sampled at intervals for determination of haemolymph osmolality (HO). Results showed that the modified diet had not only resulted in larger size shrimp at harvest, but also improved osmoregulatory capacity (OC). HO of DSSF shrimp decreased as shrimp grew bigger, whereas HO of AMA shrimp was maintained at a stable level, or showed a slightly positive linear relationship with weight. The hyper‐OC of shrimp from AMA (462 mOsm kg^?1) was greater than that from DSSF (398 mOsm kg^?1). Shrimp at AMA fed the experimental diet presented no mass moult‐associated mortalities. To further investigate the iso‐osmotic point of shrimp reared in AMA, a group of six salinity gradients were designed by mixing oceanic salts into the well water to form 5, 8.5, 11.4, 14.4, 17.8, 20.7 p.p.t. medium. HO of subadult shrimp (25 g in average) were then evaluated 48 h after they had been transferred from 5 p.p.t. pond water to the medium. Shrimp HO increased with external salinity, and a plateau formed as salinity reached at 11.4 p.p.t. and higher. The iso‐osmotic point of shrimp was estimated to be 695.5 mOsm kg^?1, equivalent to 26.1 p.p.t. in AMA well water.     

樟树无性系组培苗丘陵山地造林早期生长分析

以樟树(Cinnamomum camphora)无性系组培苗营建试验林,对林木1~5a生生长情况进行调查分析。结果表明：1a生幼林的平均树高和冠幅的分别为1.12m和1.1m;3a生平均树高、平均冠幅和平均胸径分别为3.34m、1.4m和2.94cm;5a生平均树高、平均冠幅和平均胸径依次为5.35m、1.68m和4.8cm,分别比3a生时增加60.01%、20.1%和63.26%。不同林龄的树高有极显著差异（P＜0.01）;5a生和3a生的胸径有显著差异（P＜0.05）,但冠幅差异不显著。树高、冠幅和胸径在区间组间差异均不显著,表明群体的生长表现较一致。     

分子技术在油茶中的应用研究进展

分子技术因稳定性高、标记数量多、多态性丰富等众多优点而被应用于油茶研究中。从油茶遗传多样性、品系分类及品种鉴定、文库构建和重要基因研究3个方面分别阐述了分子技术在油茶研究中的应用和最新进展,并对分子技术在油茶研究领域的发展前景进行了展望。