饲粮中添加抗菌肽对肉鸭增重及血清尿素氮、总蛋白水平的影响

240只1日龄肉鸭随机成分4组,每组设3个重复,对照组用基础日粮,试验组在基础日粮上每千克分别添加1、2、3mL抗菌肽制剂。结果显示:1)2、3mL/kg添加量组增重效果显著(P<0.05),3mL/kg添加量组最佳;净肉率升高,达到显著水平(P<0.05),其中主要是胸肌率上升;腹脂率降低但差异不显著(P>0.05);料重比无显著变化(P>0.05)。2)血清总蛋白浓度差异不显著(P>0.05),但尿素氮浓度下降,2、3mL/kg添加量组达显著水平(P<0.05),3mL/kg添加量组最低。     

影响羊肉产量和品质的因素

本文综述了品种、饲料营养、饲养方式、性别、年龄、去势、屠宰等方面对羊肉产量和羊肉品质的影响,并提出建议。     

异黄酮植物雌激素在家禽生产中的作用

异黄酮植物雌激素广泛分布于植物界,其生理活性多种多样。它具有促进家禽生长,提高产蛋性能等作用,但对其作用机制目前尚未完全明确。本文综述了近年来有关异黄酮植物雌激素在家禽生产方面的研究概况。     

披碱草和野大麦及其杂种苗期抗旱性研究

在室内人工模拟干旱条件,测定了干旱胁迫下披碱草和野大麦及其杂种幼苗的相对含水量、细胞膜透性、游离脯氨酸含量的变化。结果表明,干旱胁迫下亲本披碱草幼苗的组织相对含水量下降的幅度最低,细胞膜受害最轻,游离脯氨酸积累的最多,相对生长率最高,表现出很强的抗旱性。亲本野大麦幼苗的组织相对含水量下降的幅度最大,细胞膜受害最重,游离脯氨酸积累的最少,相对生长率最低,抗旱性弱。杂种F1幼苗的保水能力、细胞膜受害程度和游离脯氨酸积累能力、相对生长率均介于双亲之间,亦即其抗旱能力大于野大麦而小于披碱草,表现为双亲的中间型。正、反交对杂种F1的抗旱能力没有明显影响。     

利用游离小孢子培养育成早熟大白菜新品种‘豫新5号’

 ‘豫新5号’是采用游离小孢子培养双单倍体育种技术选育的一代杂种，该品种生育期60 d，单球质量23 kg，球形指数1.35，高抗病毒病、霜霉病和软腐病，净菜产量56.7 t·hm^-2，可兼作早熟、晚熟栽培。     

Variation in the development of secondary dormancy in oilseed rape genotypes under conditions of stress

Summary A substantial amount of seed is left in the fields before and during harvest of oilseed rape. Although this crop exhibits little or no primary dormancy, the absence of certain environmental cues that promote germination of imbibed seeds induces secondary dormancy. The work reported investigated the extent to which environmental stress conditions, including osmotic stress, low oxygen stress and anaerobiosis, induce secondary dormancy in oilseed rape, and examined the variation in development of secondary dormancy between and within genotypes. Osmotic stress was most effective in inducing dormancy. Anaerobic treatment produced very few dormant seeds, as did an atmosphere low in oxygen and high in nitrogen. The development of secondary dormancy under osmotic stress varied considerably between and within genotypes. Dormancy ranged from almost zero to about 60% for winter genotypes and about 85% for spring types. Within genotypes, variations occurred between seed lots and years of harvest. Temperature variations affected the percentage of dormant seeds. More dormant seeds were likely to be produced with incubation under water stress at 20 °C than at 12 °C. In winter genotypes, fewer dormant seeds were produced when incubation temperature and germination test temperatures differed. Thus, incubating at 20 °C and 12 °C, followed by germination tests at 20 °C and 12 °C, respectively, produced most dormant seeds. Also, in the winter genotypes, the potential development of secondary dormancy was positively correlated with the pattern and speed of germination of untreated seeds.     

Movement of Xanthomonas campestris pv. vitians in the stems of lettuce and seed contamination

Xanthomonas campestris pv. vitians , the causal agent of bacterial leaf spot of lettuce (BLS), can be seedborne, but the mechanism by which the bacteria contaminates and/or infects lettuce seed is not known. In this study, the capacity of X. campestris pv. vitians to enter and translocate within the vascular system of lettuce plants was examined. The stems of 8- to 11-week-old lettuce plants were stab-inoculated, and movement of X. campestris pv. vitians was monitored at various intervals. At 4, 8, 12 and 16 h post-inoculation (hpi), X. campestris pv. vitians was recovered from 2 to 10 cm above (depending on stem length) and 2 cm below the inoculation site. Xanthomonas campestris pv. vitians was also recovered from surface-disinfested stem sections of spray-inoculated plants. Together, these results are consistent with X. campestris pv. vitians invading and moving systemically within the vascular system of lettuce plants. To investigate the mechanism of seed contamination, lettuce plants at the vegetative stage of growth were spray-inoculated with X. campestris pv. vitians and allowed to develop BLS. Seed collected from these plants had a 2% incidence of X. campestris pv. vitians external colonization, but no bacteria were recovered from within the seed.     

民勤绿洲生态气候资源及其利用

民勤绿洲边缘 ,光照丰富、温差大 ,有利于农产品质量的提高。但是水资源缺乏 ,地下水位急剧下降和土地沙化是民勤绿洲农业生产的首要问题。如何充分利用现有生态资源 ,并充分提高其利用率是摆在我们面前的一个主要课题。只有通过引进优良品种 ,调整农业种植结构 ,大力推广节水灌溉技术 ,才是解决上述问题的有效途径     

离体条件下水稻种衣剂对串珠镰刀菌生长及形态毒理影响

 检测了黑龙江水稻主产区4个当地主栽品种的种子内部镰刀菌寄藏情况,测定了20%克福甲和20%克多甲种衣剂对种子带菌消毒处理效果及对水稻串珠镰刀菌(Fusarium moniliforme)的抑菌作用和联合毒力,并借助扫描电镜观察了上述2种混配种衣剂对串珠镰刀菌的形态毒理影响。结果表明,种子内部镰刀菌的分离频率高达56.7%~96.0%,其中串珠镰刀菌的分离频率为32.6%~48.2%,2种种衣剂对带菌种子具有显著的消毒处理效果。20%克福甲和20%克多甲种衣剂对镰刀菌F.moniliforme的毒力指数分别为457.11和802.04,增效倍数分别为6.53和0.13。20%克多甲种衣剂(多菌灵:甲基立枯磷为5:5,W/W)对串珠镰刀菌的抑菌作用优于20%克福甲种衣剂(福美双:甲基立枯磷为8:6,W/W),增效作用低于20%克福甲种衣剂。电镜观察表明,种衣剂低浓度至高浓度处理下均可引起串珠镰刀菌菌丝不同程度的异常生长,表现为主菌丝局部膨大或形成菌丝束,菌丝顶端异常膨大、缢缩或形成穗状和花絮状分枝。     

玉米疯顶病种子传播研究

连续3a对不同来源的玉米种子,利用显微镜镜检和试种观察植株发病显症的方法,检测其携带玉米疯顶病病菌状况。结果表明,病株病穗籽粒、病株健穗籽粒、病田健株籽粒都有较高的带菌率。因此,病菌随种子调运远距离传播是造成各地病害突发的主要原因。