来宾市野生南方红豆杉资源现状及保护策略

红豆杉属于我国一级保护珍贵植物。通过简述来宾市野生南方红豆杉资源现状,综合内外因素分析了濒危原因,提出了野生南方红豆杉保护对策。     

五味子及其提取物在鸡日粮中的应用研究

目前五味子及其提取物被广泛应用于畜牧生产上,通过介绍五味子及其提取物对鸡生长性能、抗氧化性能及免疫功能的影响,为五味子及其提取物在养禽生产中的应用提供理论基础。     

不同光照和土壤水分对望天树种子发芽的影响

[目的]解决望天树在人工繁育方面存在的技术难题。[方法]研究不同光照和土壤水分对望天树种子发芽率及出苗情况的影响。[结果]望天树种子在光照强度40%、土壤含水量60%的条件下发芽率最高。[结论]该研究为望天树的迁地保护、种群恢复及开发利用等提供一定的基础资料。     

南方白菜型油菜自交衰退和杂种优势利用方式的研究

以连续自交三代的南方白菜型油菜品种为材料进行自交、兄妹交、姐妹系间交和开放授粉，观察自交后代衰退程度及杂交后代优势程度。结果表明南方白菜型油菜自交严重衰退、连续自交四代，其主要农艺性状与开放授粉或与姐妹系间的后代差异达显著或极显著水平。自交后代纯合性越好，则杂交Ｆ１优势率越大。同一种繁殖方式，杂交Ｆ１优势率与亲本的一般配合力有关。     

妃子笑与鹅蛋荔枝花芽分化期间内源激素的变化

研究妃子笑和鹅蛋荔枝在花芽分化期间内源赤霉素（GA3）、脱落酸（ABA）玉米素核苷（ZR）和生长素（IAA）的动态变化。结果表明：2个品种在整个荔枝花序分化过程中内源GA，的含量不断的下降；在嵛期内源ABA的含量下降、中期上升和后期下降；前期内源ZR的含量下降而后上升；前期内源IAA的含量不断的下降后上升。     

荔枝小孢子发生和雄配子体的形成

应用光学显微镜和扫描电镜技术,观察了荔枝小孢子发生和雄配子体的形成,结果如下:花药四室,花药壁由5层细胞组成,小孢子四分体为四面体型,小孢子母细胞胞质分裂为同时型。具腺质绒毡层。成熟花粉为两细胞型。花粉粒扁球形,极面观呈钝三角形,赤道面观为椭圆形,具三沟孔。花粉壁务内外两层,表面具条纹状纹饰。花粉粒发育过程中,常出现退化现象,在低产的植株中尤为明显。     

3种工业废水对中国对虾幼体及仔虾的急性毒性效应

通过室内毒理实验,研究印染废水(主要有毒物质为苯胺C6H5NH2和苯酚C6H5OH,质量浓度分别为20 mg/L和24 mg/L)、电镀废水(主要有毒物质为锌、铜和铅,质量浓度分别为1 970 mg/L、9 mg/L和7.5 mg/L)、农药废水(主要有毒物质为久效磷和亚磷酸盐二甲酯)及其混合废水对中国对虾(Peanaeus chinensis)无节幼体和仔虾的急性毒性作用.结果表明,印染废水、电镀废水、农药废水及其混合物对无节幼体48 h LC50(95%可信限区间)和96 h LC50(95%可信限区间)分别为2.27%(1.72%～2.99%)、0.29%(0.22%～0.37%)、0.86%(0.64%～1.15%)及0.30%(0.22%～0.40%)和1.03%(0.79%～1.34%)、0.16%(0.12%～0.19%)、0.38%(0.30%～0.48%)及0.18%(0.13%～0.24%);对仔虾48h LC50(95%可信限区间)和96 h LC50(95%可信限区间)分别为3.51%(2.38%～5.18%)、0.40%(0.29%～0.55%)、2.06%(1.34%～3.17%)及0.52%(0.39%～0.71%)和1.44%(1.06%～1.96%)、0.21%(0.15%～0.29%)、0.71%(0.51%～0.99%)及0.22%(0.17%～0.29%).3种工业废水的毒性从大到小依次为:电镀废水、农药废水、印染废水,无节幼体较仔虾对这废水的毒性更为敏感.3种废水以等体积混合时,对无节幼体和仔虾的联合毒性表现为协同作用.     

中国对虾5个地理群体的RAPD分析

采用随机扩增多态DNA(RAPD)技术对取自辽东湾、渤海湾、海州湾、乳山湾及海洋岛5个群体的中国对虾共95个个体的遗传多样性进行分析。14个随机引物共检测出103个位点(200～2500bp),各群体的多态位点比例在31．07％～34．95％之间。遗传距离显示中国对虾群体间有一定遗传分化,其中辽东湾和乳山湾群体问的遗传距离最大(0．0742),而辽东湾和渤海湾群体间的遗传距离最小(为0．0243),群体间的遗传分化系数为0．2083。整体来看,中国对虾的遗传变异水平较低,遗传多态度为0．1621。用UPGMA对5个群体进行聚类分析,构建谱系关系图。     

Effects of protein restriction with subsequent realimentation on growth performance of juvenile Chinese shrimp (Fenneropenaeus chinensis)

The effects of protein restriction in the diet with subsequent realimentation on growth responses of juvenile Chinese shrimp, Fenneropenaeus chinensis (initial mean wet weight 1.347 g), were investigated. The control group (Group C) was fed an adequate diet containing 44.6% crude protein and 18.5 kJ gross energy/g dry matter throughout the experiment. For treatment Groups T₁₅ and T₃₀, in the restriction phase (weeks 1–2) dietary crude protein contents were reduced to 15.0% and 29.3%, respectively, with constant energy supply, while in the realimentation phase (weeks 3–6) they were supplied with the same diet as the control group. Protein restriction led to significant decrease in specific growth rates and body weight of shrimp. However, when the shrimp were transferred from protein restriction to realimentation, they had significantly increased specific growth rates in terms of dry matter, protein and energy (SGR_d, SGR_p and SGR_e) compared with the control shrimp. At the end of the experiment, the shrimp in Group T₃₀ achieved complete growth compensation, while those in Group T₁₅ were still significantly smaller than the controls. As dietary protein levels reduced, feed conversion efficiencies and apparent protein digestibility decreased, but feed intake and protein efficiency ratio increased. The shrimp responded to a change from protein restriction to realimentation by displaying improved feed conversion efficiencies (FCE_d, FCE_p and FCE_e) compared with the controls, although those in Group T₁₅ delayed in showing the enhanced FCE values. In the initial 2-week realimentation, the shrimp in Group T₁₅ showed significantly higher feed intake, and lower apparent digestibility of dry matter and protein than those of the controls. There was no significant difference in protein efficiency ratio among all groups in the realimentation phase. The above results suggest that compensatory growth in Group T₃₀ is mainly dependent on improved feed conversion efficiencies, while that in Group T₁₅ is attributable to both improved feed conversion efficiencies and increasing feed intake. After 2-week restriction, the shrimp showed lower body crude protein, lipid and energy content, and higher moisture and ash content than the controls. However, during the course of realimentation, the differences between the previously protein restricted shrimp and the controls diminished. This indicates that compensatory growth after a period of protein restriction in juvenile Chinese shrimp was accompanied by a complete recovery in body composition and energy content.