鸡霍乱口服弱毒疫苗的研究

用经过选择的禽多杀巴氏杆菌自然弱毒菌株Ｒ１－２３菌株制成的鸡霍乱固体培养口服弱毒疫苗，其安全剂量接近于２００个免疫剂量。该口服苗两次饮水免疫的最适总剂量为每羽５０亿个活菌，最佳间隔时间为４８小时。免疫鸡第二次饮苗后第３天即可产生较好的免疫保护率（７／８）。免疫鸡对异型强毒株Ｐ１０５９（８∶Ａ）、Ｐ２７２３（９∶Ａ）和同型强毒株Ｃ４８－１（５∶Ａ）滴鼻攻击的近期保护率平均为５／１０、６／１０和９／１０。６个月免疫期的平均保护率为７６．７０％（４６／６０），一万多羽鸡田间试验结果表明，免疫后２个月的平均保护率为９３．１０％（２７／２９），６个月的平均保护率为７３．５０％（２５／３４），除对产蛋率有轻度影响（下降１．２７％）外，无其它不良反应。野外大面积使用结果表明，该口服苗不但性能稳定，免疫原性优良，而且安全可靠，适用于鸡口服免疫。     

CCC对葡萄试管苗生长的影响

ＣＣＣ对葡萄试管苗的茎叶生长有显著的抑制作用，茎的高度、节数及节间长度均有明显减少；ＣＣＣ对生根率没有明显影响，但对插段的生根数量有较大的影响，在一定浓度范围内（２０～８０ｍｇ／Ｌ）ＣＣＣ处理的生根数量有所增加，其中以４０ｍｇ／Ｌ时增加最多，为８．６７～８．９５条／段。但ＣＣＣ对根系伸长有明显的抑制作用，随着ＣＣＣ浓度的升高根长逐渐变短；从干、鲜重的变化来看，ＣＣＣ处理后墓叶的干、鲜重是随着浓度的升高而减少，但根系的干、鲜重在０～４０ｍｇ／Ｌ范围内呈略增加的趋势，４０ｍｇ／Ｌ以后则大幅度减少。     

用现代工业理念发展皖北果业

年来随着市场经济的不断发展,“卖果难”成了皖北果区一个最突出的问题。如何依托果业兴办工业，着眼工业调整果业，拉大加宽产业链，提高果品附加值，带动果农增产增收。为此，必须以调整结构为核心，注重产业化经营的拉动，突出龙头企业扶持、基地建设和市场体系的培育为重点，树立用现代工业理念谋划果业发展的思想。     

溴隐停对惠州麻肉种鸡产蛋性能的影响

研究目的在于探讨多巴胺受体激动剂(溴隐停)对地方良种肉鸡繁殖性能的影响。方法从628只28周龄健康的“惠州麻”黄羽肉种鸡群中随机选取1组鸡笼内的40鸡作为实验组,其余的作为对照组。实验组鸡群喂服溴隐停,每只鸡每天1.25mg,连用4d,停用4d后再用4d,对照组不使用。结果在4周的实验期内实验组和对照组的产蛋率分别为83.86%和69.96%;破蛋率分别为1.28%和1.69%,畸形蛋率分别为4.33%和1.19%;实验组平均每只鸡的产蛋总数比对照组多3.89个、合格种蛋数多3.26个;药物处理对平均蛋重无显著影响;使用溴隐停能够提高鸡血液中的雌激素水平。结论溴隐停能够通过抑制地方良种肉鸡体内促乳素的合成与分泌,减少抱窝现象的发生,提高其繁殖性能。     

利用生物工程提高乳锌含量技术

文章利用生物转化工程原理将硫酸锌加入牛饲料间接强化牛乳进行了试验观察,效果转好。强化后牛乳无外观质量变化,乳锌经一个高峰期四周后处于稳定状态,其含量可满足婴幼儿生长发育的需要。同时,还提出了硫酸锌强化饲料的适量剂量。并就乳牛饲龄、胎次、体重、产乳期对乳锌的影响和强化方法进行了探讨分析。通过此项研究,为解决目前缨幼儿缺锌问题,开发了一个吸收率高、副作用小、安全可靠的补锌源。     

尕海地区弃耕地土壤可溶性盐分测定

１９９０～１９９３年在柴达盆地尕海地区弃耕地进行土壤可溶性盐分测定，测定结果，该地区土壤盐分组成为氯化物－硫酸盐和硫酸盐－氯化物，大部分地区耕层盐分含量小于１０ｇ．ｋｇ＾－１，少部分盐荒地表层含盐量高达７０ｇ．ｋｇ＾－１，牧草生长季节中，土壤盐分含量最低期在６月份。     

陆地棉功能叶不同生育时期酶活性及脂质过氧化作用的研究

对不同熟性棉花品种功能叶几种酶活性及脂质过氧化水平（以丙二醛含量表示）的研究结果表明，超氧物歧化酶（ＳＯＤ）活性在吐絮前呈波动上升，吐絮盛期争剧下降；丙二醛（ＭＤＡ）含量吐絮前缓慢上升，吐絮后明显增加；过氧化氢酶（ＣＡＴ）活性在结铃以前随叶片发育而上升，结铃后急剧下降；过氧化物酶（ＰＯＤ）活性始终呈上升趋势。进一步对ＰＯＤ同工酶进行电泳发现，其酶谱构成随生育进程而变化，早熟品种在开花期酶带条数最多     

SS-1型声速实验仪的研制

本文阐述了SS—1型声速实验仪的原理、结构和测量方法。波动学和分子物理学是物理学中的重要组成部分,"声速的测量"和"Y值的测量"两个实验有助于学生对波动相位的空间分布、谐振动的合成、李萨育图、能量按自由度均分原     

Correlation between hydrolytic enzyme activities measured in bean seedlings afterTrichoderma koningii treatment combined with pregermination and the protective effect againstPythium splendens

An experimental protocol consisting in the colonisation of pregerminated bean seeds dressed withTrichoderma sp. was used in order to study the mechanisms correlated with the protective effect againstPythium splendens. Seed dressed with TH-11 (T. koningii) for 24 h presented a higher protective effect and a higher level of seed colonisation as compared to those dressed with TH-13 (T. longibranchiatum). The levels of seed coat colonisation by TH-11 and TH-13 was shown to be correlated with the carboxymethylcellulase activity, as measured in the seed coats retreived from germinating dressed bean seeds. The seed coat colonisation was also associated with an increased activities of endo-1,3--glucanase and endochitinase measured in seed extracts, and an inhibitory effect of seed extracts onPythium sporangia germination. Pretreatment of TH-13-dressed seeds with a commercial cellulase improved all parameters mentioned above, thus suggesting a role of cellulase activity in the colonisation process and the linked protective effect. The possible role of hydrolytic enzymes in the protective effects is discussed.     

Epidemiology of beet necrotic yellow vein virus in sugar beet at different initial inoculum levels in the presence or absence of irrigation

A field experiment was set up in 1988 to study the development of rhizomania disease of sugar beet at different inoculum levels of beet necrotic yellow vein virus (BNYVV) in soil. Five, tenfold different, inoculum levels were created by addition of the approximate amounts of 0, 0.5, 5, 50 and 500 kg infested soil per ha (the latter corresponding to 0.01% v/v calculated to the tillage layer). A drip irrigation treatment was applied to study the influence of soil moisture on disease. Susceptible sugar beet, cv. Regina, was grown for three consecutive years.In the first year, root symptoms were not observed, but BNYVV-infected plants were detected by ELISA in low numbers at all inoculum levels at harvest. After late drilling in 1989, high numbers of infected plants, up to 90–100% in plots with the highest inoculum level, were detected already in June. Root symptoms were also observed from June onwards. In both these years disease incidence increased in time and was significantly influenced by the initial inoculum level. In the third year, the whole field was heavily diseased, and only for the non-irrigated plots incidence differed for different initial inoculum levels. The expression of symptoms by BNYVV-infected plants was influenced by initial inoculum level, thus by the amount and timing of primary infection.Root weight at harvest was not affected, but sugar content decreased with increasing inoculum level already in 1988, leading to a reduction in sugar yield of 10% at the highest inoculum level. In 1989, both root weight and sugar content decreased progressively with increasing inoculum level, resulting in sugar yield reductions of 11–66% (down to approximately 3000 kg ha^–1) for low to high inoculum levels compared to the control. As the control plots became contaminated, all yields were low in 1990, still showing a decrease with increasing inoculum level in the non-irrigated plots, but an overall mean sugar yield of 3323 kg ha^–1 for the irrigated ones.Sodium and -amino nitrogen content of the root, additional quality parameters determining extractability of sucrose, showed an increase and decrease, respectively, with increasing initial inoculum level already in the first year. The relative differences in contents compared to those from the control were largest for Na content. A significant negative correlation was found between Na (mmol kg^–1 root) and sugar content (% of fresh weight); linear for 1988, exponential for 1989 and 1990.In spring 1989, the infestation of individual plots was assessed using a quantitative bioassay estimating most probable numbers (MPNs) of infective units of BNYVV per 100 g dry soil. The relationship between the MPns determined and root weight, sugar content and sugar yield at harvest could be described by Gompertz curves. The increase in disease incidence with increasing MPN in 1989 was adequately fitted with a logistic equation.