Supplemental effect of cholyltaurine and soybean lecithin to a soybean meal-based fish meal-free diet on hepatic and intestinal morphology of rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>

The supplemental effects of cholyltaurine and soybean lecithin to a defatted soybean meal (SBM)-based fish meal-free diet on the hepatic and intestinal morphology of rainbow trout Oncorhynchus mykiss were investigated. A fish meal-based diet (FM), three fish meal-free diets supplemented either with soybean lecithin (SL), bovine gall powder (BG) or cholyltaurine (C-tau) and an unsupplemented fish meal-free diet (NFM), were given to fish (−11 g) for 10 weeks. The growth was the lowest in fish fed diet NFM, intermediate in fish fed diet SL and the highest in fish fed diet FM, BG and C-tau. Hepatocytes of fish fed diet NFM were atrophied, and the distal intestine of these fish showed abnormal features: disintegrated microvilli and fatty degeneration in epithelial cells and increased amount of connective tissue in the submucosa. Hepatic and intestinal histological features in fish fed diets SL, BG and C-tau were similar to those in fish fed diet FM. These results indicate that soybean lecithin, bovine bile salts and cholyltaurine have similar effects on normalizing the hepatic and intestinal morphologies of rainbow trout fed the SBM-based diet, although growth promotion effect was limited in the soybean lecithin.     

元蘑孢子萌发融合育种试验与研究

试验采用孢子萌发融合技术获得元蘑菌株,并对其进行了产量和形态指标测定,选育出的菌株经3年的栽培试验,产量高出常规品种15%,菇形好,命名为元蘑1号。     

The significance of meandering channel morphology on the diversity and abundance of macroinvertebrates in a lowland river in Japan

• 1. Many rivers and streams across the world have been channelized for various purposes. Channel cross‐sections of meandering rivers are asymmetrical and have cross‐sectional diversity in their physical environment; cross‐sections of a channelized river are typically trapezoidal and have little cross‐sectional diversity, both in physical and ecological conditions. Several programmes to restore stream meanders have been undertaken to improve river ecosystems degraded by channelization. However, the association between diversification in the physical environment due to meander restoration and the macroinvertebrate community structure is poorly known.
• 2. This study of a lowland river in Japan assessed how the cross‐sectional diversity of the physical environment changed with restoration of a meander in a channelized river, and how the macroinvertebrate communities responded to the changes in physical habitat variation. Comparisons were made between the macroinvertebrate communities of a channelized reach, the restored meandering reach, and a natural meandering reach.
• 3. Natural meandering and restored meandering reaches showed higher cross‐sectional diversity in physical variables and total taxon richness across a reach than did the channelized reach. Almost all taxa observed in the natural and restored meandering reaches were concentrated in the shallowest marginal habitats near the banks. Shear velocity increasing with water depth had a negative association with macroinvertebrate density and richness.
• 4. This study demonstrated that the shallow river bed along the inside of bends formed point bars that provided a highly stable substrate, a suitable habitat for macroinvertebrates in a lowland river. It is concluded that meander restoration could be an effective strategy for in‐stream habitat restoration in lowland meandering rivers.

Copyright © 2007 John Wiley & Sons, Ltd.     

Allometric and ontogenetic patterns related to feeding of a neotropical fish, Satanoperca pappaterra (Perciformes, Cichlidae)

Abstract –  This study aims to analyse whether Satanoperca pappaterra changes its feeding habit throughout ontogenetic development, and whether morphological ontogenetic patterns are related to its feeding habit and food capture. We collected 258 individuals in the Cuiabá river basin (Brazil) for analyses. There was a weak relationship between diet and body size, as evidenced by size class and multivariate analyses, and niche breadth did not vary strongly during ontogenetic development. Eight morphometric variables were measured in each individual. We found an isometric relationship for mouth height and width, and for head length. We found positive allometry for snout length and body height in relation to body length, whereas this relationship for intestine length and eye diameter showed negative allometry. These results suggest that morphology and consequently diet vary weakly during ontogenetic development of S. pappaterra .     

Classification of Tomicus Species

Both morphological characters and a portion of of 28S rDNA sequences were used to identifying Tomicus species.The specimens were classed into groups with the following characters: 1) granules or punctures on interstria 2 on the declivity of the elytra;2) length of the elytral interstrial hairs and hairs arising from punctures;3) arrangement of pronotal punctures and hairs.These characters could be clearly examined under a binocular microscope at 30×magnification and they were applicable and valuable for the forest entomologists to identify Tomicus species.The phylogenetic tree established with difference in 28S rDNA sequence of D2 region revealed that the specimens of each group identified by morphological characters were also grouped together.The genetic distances of intra-species, inter-species and inter-genus were not overlapped. Genetic divergence of 28S rDNA was also useful for identifying Tomicus species.     

减源处理下小麦粒重稳定性QTL的定位分析

粒重稳定性是小麦稳产性的重要评价指标。为了发掘小麦在遭受虫害等减源逆境伤害时影响粒重稳定性的QTL,以小偃81和西农1376杂交衍生的重组自交系（RILs）群体为试验材料,设早播和晚播两个播期,对减源处理下该群体的粒长、粒宽和千粒重进行表型分析,同时计算减源处理与对照处理的表型比值,进而估测发育稳定性,并利用50K芯片构建的遗传连锁图谱进行QTL定位。结果表明,与对照处理相比,减源处理下RIL群体的粒长、粒宽和千粒重均显著下降。采用完备复合区间模型对不同处理的表型值、表型比值分别进行QTL定位,共检测到18个QTL,分布于2A、3A、3B、3D、4B、4D和5D染色体上,其中有8个QTL在减源处理和对照处理中均表达, Qgl.nwafu-5D.3和 Qkgw.nwafu-5D均在早播对照处理和晚播减源处理中被检测到,平均可解释表型变异的8.73%和8.19%,为稳定QTL,且 Qgl.nwafu-5D.3也在早播减源处理中被检测到,推测这2个稳定QTL可能为新发现的位点。控制表型比值的QTL大多与控制粒长、粒宽和千粒重的QTL区间重合,推测维持减源后粒重稳定性的QTL与控制粒长、粒宽和千粒重的位点紧密连锁或存在“一因多效”现象。     

‘云蔗05-51’与‘云蔗081609’苗期氮吸收利用效率的比较研究

甘蔗（Saccharum spp. hybrid）是我国食糖生产的重要原料,当前生产中普遍存在施氮量高而氮肥利用率低的问题。除了优化施肥管理,种植氮高效的甘蔗品种也是减氮增效的重要途径之一。本研究以云南蔗区推广的早熟高产高糖甘蔗品种‘云蔗05-51’和‘云蔗081609’为试验材料,设置0、0.1、0.5、1、5、10 mmol/L 6个供氮水平开展水培试验,在苗期测定植株生物量、根系形态、氮浓度与累积量、氮素吸收利用效率等指标。结果表明：（1）2个品种地上部、根系及整株生物量均随供氮水平的升高呈先升后降趋势,‘云蔗081609’根系生物量先于其地上部达到峰值,‘云蔗05-51’则相反,‘云蔗05-51’和‘云蔗081609’达到最佳生长需要的供氮量分别为0.5、1 mmol/L,相同供氮水平下‘云蔗081609’生物量高于‘云蔗05-51’;（2）随供氮水平上升,2个品种的根系总长度和平均根直径先上升后趋于稳定,根表面积持续增加,比根长先升后降,相同供氮水平下‘云蔗081609’的根系总长度、平均根直径和根表面积高于‘云蔗05-51’,比根长则低于‘云蔗05-51’;（3）2个品种植株氮浓度及累积量随供氮水平的升高总体呈先上升后稳定的趋势,相同供氮水平下‘云蔗081609’的植株氮累积量高于‘云蔗05-51’;（4）随供氮水平的增加,2个品种的单位根长吸氮量呈先升后稳定的趋势,单位根表面积吸氮量则呈先升后降并趋于平稳,氮素生理利用效率均随供氮水平升高显著降低,在0.1~10 mmol/L范围内‘云蔗081609’单位根长的吸氮量高于‘云蔗05-51’,但单位根表面积吸氮量变化趋势基本一致,品种间氮素生理利用效率无差异。综上表明,‘云蔗081609’在苗期对氮的吸收量高于‘云蔗05-51’主要得益于更好的根系生长,苗期适宜需氮量低于‘云蔗05-51’。     

水稻超高产育种的理论和方法

 水稻超高产育种是当前世界性的热门课题，也是难题。现在我国人口已近十二亿，水稻是我国粮食生产的大头。高产更高产，难度越来越大。它的超高产育种，既无现成的理论和方法可循，就只能摸索前进。本文试图将几十年来多少人的汗水心血所凝成的宝贵经验，全面加以分析整理，藉以进一步完善过去所提出的理想株形与优势利用相结合的大方向，优化性状组配以及杂交后代选择标准等理论和方法，以供国内外同行参考试用。     

大豆疫霉菌生物学性状的遗传与变异

大豆疫霉菌引起的大豆疫病是大豆上危害严重的毁灭性病害之一.采用经典遗传学方法研究大豆疫霉菌单孢后代的菌丝生长速率、菌落形态、产孢量以及同宗配合性状的遗传变异,以期为有效控制大豆疫病的发展和蔓延奠定基础.结果表明,菌落形态、生长速率和同宗配合性状在单孢后代可稳定遗传,控制上述性状的遗传因子是纯合的;大豆疫霉菌的游动孢子产生能力在单孢后代发生连续性变异,表明这种性状可能是数量遗传性状,也可能控制这种性状的基因为杂合基因或细胞质遗传因子.研究结果初步揭示了大豆疫霉的遗传特征、遗传多样性及多样性产生的遗传学基础.     

不同地区潜伏侵染香蕉果实的炭疽菌生物学特性研究

不同保湿时间、孢子浓度、营养和光照等条件，对潜伏侵染在香蕉果实中的芭蕉炭疽菌的分生孢子萌发、菌丝体生长和产孢影响试验结果表明，来自广东茂名、化州、台山和海南琼山的芭蕉炭疽菌分离系Ｉ－ＩＶ号，均表现出在１００％ＲＨ下，３ｈ后分生孢子开始萌发，９ｈ后达最高；ＲＨ〈９０％时，萌发率急剧下降；孢子浓度超过１×１０＾６个／ｍｌ时，不利孢子萌发；增加营养可提高孢子萌发率；黑暗较光照条件下更有利于孢子萌发和菌丝