饲粮中铜添加量对断奶至2月龄长毛兔生产性能和血清指标的影响

本研究旨在探讨饲粮中铜添加量对断奶至2月龄长毛兔生产性能、血清生化指标及血清中酶活性的影响。选用蒙阴细毛型长毛兔180只,随机分为6组,每组30只,试验兔单笼饲养。6组试验兔分别饲喂在基础饲粮中添加0、10、20、40、80和160 mg/kg铜(添加形式为五水硫酸铜)的试验饲粮,试验饲粮中铜含量的实测值分别为3.25、13.13、23.40、43.56、83.58及163.87 mg/kg。预试期为7 d,正试期为23 d。结果表明:饲粮中铜添加量对长毛兔平均日增重(ADG)、料重比(F/G)的影响极显著(P0.01),当铜添加量为80 mg/kg时,ADG最高,F/G最低。饲粮中铜添加量对长毛兔胎毛产量、毛直径及皮张面积的影响不显著(P0.05)。饲粮中铜添加量对长毛兔血清中总蛋白(TP)、白蛋白(ALB)、球蛋白(GLB)、尿素氮(UN)含量及白球比(A/G)均有显著影响(P0.05)。血清中UN含量随饲粮中铜添加量的升高呈现先下降后升高的趋势,当铜的添加量为80 mg/kg时,血清中UN的含量最低。饲粮中铜添加量对长毛兔血清中铜锌超氧化物歧化酶(Cu-Zn SOD)活性的影响不显著(P0.05),但对血清中铜蓝蛋白(CP)活性的影响显著(P0.05)。随着饲粮中铜添加量的升高,血清中铜蓝蛋白活性先升高后降低,在铜添加量为80 mg/kg时有最高值。饲粮中铜添加量对长毛兔肝脏指数有显著影响(P0.05),而对其他内脏器官指数无显著影响(P0.05)。当铜添加量为20 mg/kg时,肝脏指数最高。综合本试验测定指标,推荐断奶至2月龄长毛兔饲粮适宜的铜添加量为20~80 mg/kg。     

Photosynthetic Capacity of Wintering Citrus in Relation to Temperature Conditions and Dormancy

对在不同温度条件下越冬的柑橘苗光合能力和生长活性进行研究的结果显示，室外橘苗在冬季光合能力的下降，主要是由于低温作用于叶子的后效，而不是由于植株或器官的休眠状态．光合降低的程度和升温后光合恢复所需的时间随低温处理时间的增长而增加．光合下降过程中叶子细胞间隙与环境中ＣＯ２浓度的比值最初比较恒定，然后逐渐增大．这一事实表明，降温初期气孔导度和叶肉导度同时协调地下降，以后叶肉导度的下降逐渐占据优势，而在恢复过程中则相反．仅仅茎部或根部受低温处理也会导致光合能力的明显降低．然而不同的低温处理方式对叶子水势的影响有明显差别．所以低温通过减少供水造成叶子水分亏缺虽然可能是导致光合下降的原因之一，但不像是唯一的原因．在完全没有光参与的条件下单靠低温就足以使光合能力明显下降，可是不能排除冬季在田间条件下同时也发生因低温而加强的光抑制．     

浅谈投资决策分析的基本方法

长期投资是企业主要的投资方式，在投资实施之前，必须运用科学的方法进行有效的分析判断。本文比较分析了非折现的现金流量法和折现的现金流量法两类投资决策分析的运算过程，以及两种方法的利弊，并介绍了投资决策敏感性分析的方法。在实际工作中，应该运用多种分析方法进行比较分析，才能保证投资决策的正确性。     

利用壳聚糖防治柑橘采后青霉病的研究

利用平板法测定了不同浓度壳聚糖对柑橘青霉病菌的抑制作用,结果发现,随着壳聚糖浓度的增大,抑制作用逐渐增强。当壳聚糖浓度超过0．5％时,完全抑制病菌的生长。将柑橘用壳聚糖溶液浸泡处理后挑战接种柑橘青霉病菌,发现壳聚糖溶液可以有效防治病害的发生,防治效果达到81％,优于常用杀菌剂多菌灵的防治效果。     

影响柑桔球形合子胚离体培养的若干因素

通过对柑桔球形合子胚不同发育期的分离培养、不同基本培养基及附加物、蔗糖浓度等因素对柑桔合子胚离体培养影响的研,结果表明:授粉后50d是柑桔合子胚离体培养的最适时期;Whiet基本培养基比MS基本培养基更适于柑桔球形合子胚离体培养。适当增加培养基的渗透压和添加水解乳蛋白,特别是袖子胚乳 ,可提高幼胚的诱导率,有利于柑桔球形胚的发育。比较适宜的蔗糖浓度为10%一 15%,水解乳蛋白浓度为400mg/L     

Comparison of beetle samples captured by traps with those of flowers in a broad-leaved forest

Beetle samples were compared between catches by traps and those on flowers in a Japanese beech (Fagus crenata Blume) forest, in Minakami, Gunma Prefecture, Japan. White plastic traps (Sankei Chemical Co., Ltd.) equipped with benzyl acetate were set out for a month from July 23 to August 23, 1993, and all beetles captured were collected every six days. During six days from August 10 to August 16, beetles were captured with traps and on wild flowers (Aruncus sylvester Kostel andAngelica polyclada Franch) at three hour intervals. Over the month, the traps captured 1,677 individuals of 73 species of 20 families, which included 16 (89%) species captured on flowers in the six-day period. Over the six days, the traps captured 327 individuals of 21 species of 12 families, compared with 685 individuals of 18 species of 5 families on the flowers; all of the families and nine (50%) species of beetles taken on the flowers were also captured by the traps; all of the species with more than five individuals captured on the flowers were also trapped. This suggests that capture by traps might sufficiently cover the beetle fauna on flowers. The number of species and individuals, as well as their changing patterns, however, varied more irregularly during the six-day period with the traps than with those on the flowers. A part of this paper were presented at the 46th meeting of the Kanto Branch of the Japanese Forestry Society (1994) These English titles are tentative translation by the authors from the originals     

Influence of the leaf iron contents on the ferredoxin levels in citrus plants

Partial purification of the ferredoxin form crude extracts and their spectrophotometric quantification by means the measuring at 312 nm permit the determination of the ferredoxin levels in leaves of citrus plants. The leaf contents of this protein are related with the total iron concentrations, as well as with the iron chlorosis symptoms of the plants. On the other hand, iron infiltration treatments on intact leaves enhanced the sythesis of the ferredoxin     

柑橘响应黄龙病侵染的韧皮部蛋白2基因CsPP2B15的克隆与表达分析

黄龙病病原菌诱导柑橘筛孔胼胝体过度积累是其致病的一个重要因素。柑橘韧皮部蛋白（Phloem Protein,PP）在筛孔胼胝体积累中起着重要作用。为研究柑橘韧皮部蛋白响应黄龙病亚洲种（Candidatus Liberibacter asiaticus,CLas）侵染的功能,克隆获得了一个响应黄龙病侵染差异表达的PP基因CsPP2B15的编码区和长1.5 kb的启动子序列,并以高感品种锦橙和耐病品种酸柚老叶和嫩叶为材料,进行基因表达分析。结果发现,CsPP2B15在高感品种锦橙嫩叶中受CLas诱导显著上调表达,而在耐病品种酸柚嫩叶中受CLas诱导显著下调表达,且在叶肉中的表达量显著高于叶脉。嫩叶和嫩梢被认为是柑橘响应黄龙病侵染的早期原初侵染部位。因此,CsPP2B15可能在CLas侵染柑橘早期中起重要作用。CsPP2B15启动子的顺式作用元件预测分析发现,CsPP2B15启动子含有许多与逆境和激素有关的顺式作用元件。进一步构建了CsPP2B15启动子控制GUS报告基因的植物表达载体,转化枳[Poncirus trifoliata（L.）Raf.]上胚轴。GUS组织化学染色和GUS酶活性测定均表明,CsPP2B15启动子具有较强的韧皮部组织特异性。     

A single injection of corifollitropin alfa supplemented with human chorionic gonadotropin increases follicular recruitment and transferable embryos in the rabbit

Superovulation protocols are designed to achieve maximum embryo yields. Nevertheless, ovarian response control and the quality of obtained embryos are still a challenge. On the other hand, to save the superovulated embryos until their subsequent use, it is usual to cryopreserve them, so it is also crucial to assess their cryotolerance. The aim of this study was to compare the efficacy of a single injection of corifollitropin alfa (FSH‐CTP) alone or supplemented with human chorionic gonadotropin (hCG) and to determine the impact of this stimulation on in vitro and in vivo development of fresh or devitrified embryos. Our outcomes showed that ovulation rate and recovered embryos were significantly increased when hCG was used. In vitro development of fresh and devitrified embryos and survival at birth were not significantly affected by superstimulation treatment. Results of this study suggest that a single injection of long‐acting FSH‐CTP supplemented with hCG can be effectively used in rabbits to elicit an increase in ovulation rate and number of recovered embryos. Furthermore, we demonstrated that hCG supplementation had no negative effects in embryo cryosurvival and development, showing similar survival rate at birth than FSH‐CTP alone group.