自发气调包装对蜂糖李采后生理及贮藏品质的影响

以蜂糖李为试验材料,采后通过4种不同的自发气调包装处理(PE40、PE30、PE20和微孔),对蜂糖李采后生理和贮藏期品质进行定期测定,研究不同的自发气调包装对蜂糖李采后生理及贮藏期品质的影响。通过对呼吸强度、乙烯释放率、总酚含量、PPO活性、贮藏期的微环境气体成分、果实硬度、可溶性固形物、可滴定酸、褐变指数、腐烂指数、含水率等指标的分析,发现自发气调包装袋的保鲜效果依次为PE40>PE30>PE20>微孔。在0℃条件下,采后用PE40自发气调包装处理对蜂糖李保鲜效果最好。     

高产高效栽培下春玉米生育后期冠层结构及其光合特性的研究

以郑单958为供试品种,设高产高效栽培(GCGX)和农户传统栽培(CK)2个处理,于2012年和2013年连续2 a进行田间试验,测定春玉米生育后期冠层结构及其光合特性的变化规律。结果表明：吐丝期和乳熟期株高、穗位高产高效栽培略高于农户传统栽培。与农户传统栽培相比,高产高效栽培春玉米叶面积指数较大,在生育期上表现为吐丝之后更为明显,在叶位上表现为棒三叶以下叶片最为突出;不同叶位的叶倾角高产高效栽培显著小于农户传统栽培,而叶向值均显著大于农户传统栽培,在棒三叶表现最为明显;高产高效栽培生育后期净光合速率显著高于农户传统栽培,冠层光合能力极显著高于农户传统栽培。高产高效栽培下春玉米产量为14.009 t·hm^-2(2012)和13.255 t·hm^-2(2013),均极显著高于农户传统栽培。     

黄河鲤嗜水气单胞菌的分离、毒力及用药分析

自发病黄河鲤4种组织中分离致病菌,结合形态学和16SrDNA序列分析,发现分离到的细菌属气单胞菌属。回归感染试验发现,患病鱼体出现鳃盖等多处组织出血且伴随肠炎等症状,表明引起黄河鲤发病的致病菌为嗜水气单胞菌,命名为HNAh01。半致死密度测定发现,嗜水气单胞菌HNAh01的半致死密度为1.38×10~7 cfu/mL。药敏结果表明,该致病性嗜水气单胞菌是典型的多重耐药嗜水气单胞菌,但对恩诺沙星极为敏感。因此,选择恩诺沙星对分离菌株进行体外药效学和用药分析试验。药效学试验表明,恩诺沙星对嗜水气单胞菌HNAh01的最小抑菌质量浓度为1.56ng/mL,最小杀菌质量浓度为3.12ng/mL,防耐药突变质量浓度为12.5ng/mL,耐药选择窗的范围为1.56~12.5ng/mL。用药分析结果显示,黄河鲤口服剂量为10mg/kg时对嗜水气单胞菌HNAh01的相对保护率达83%。本文研究为嗜水气单胞菌的防治提供了理论基础与实践依据。     

有机培肥与耕作方式对稻麦轮作土壤团聚体和有机碳组分的影响

为了明确不同外源有机物和耕作方式对土壤地力培育的影响,以水稻-小麦轮作系统为对象,通过2个年度(2016—2018年)大田试验研究了外源有机物(秸秆和有机肥)和耕作方式及其交互作用[稻麦秸秆还田配合旋耕(SR),稻麦秸秆还田配合翻耕(SP),秸秆不还田、增施有机肥配合旋耕(MR),秸秆不还田、增施有机肥配合翻耕(MP),秸秆不还田、不施用有机肥、旋耕深度15 cm(CKR)]对土壤团聚体和有机碳组成的短期影响。结果表明:SR处理能够降低水稻季土壤容重并增加总孔隙度。相比CKR,小麦季SR处理显著增加0.05mm水稳性团聚体含量,增加量为7.2%。此外,外源有机物和耕作对土壤有机碳活性组分具有显著影响。其中,易氧化有机碳(EOC)主要受耕作与有机物交互作用影响,酸水解有机碳(LPIc和LPII_c)主要受耕作措施的影响, SR处理的土壤EOC和LPI_c含量比CKR提高0.3～2.6 g·kg~(-1)。颗粒有机碳(POC)主要受外源有机物的影响,并且秸秆还田处理POC平均含量高于增施有机肥处理,增加量为0.75g·kg~(-1)。短期内,外源有机物和耕作及其交互作用对稳定性有机碳(黑碳和矿物结合态有机碳)的影响较小。综上,秸秆还田配合旋耕有助于提高土壤水稳性团聚体和活性有机碳的含量(EOC、LPI_c和POC)。     

山羊痘灭活疫苗免疫保护试验

将山羊痘GT4-STV42-56种毒在犊牛睾丸细胞上繁殖,收获毒液,用0.1%甲醛溶液灭活,加适量206佐剂,制成山羊痘油佐剂灭活疫苗.将疫苗以不同剂量皮下免疫接种不同种群的山羊.免疫后21 d,用AV40株强毒进行攻毒保护试验.结果显示,免疫剂量达0.5 mL时,疫苗对内蒙绒山羊的保护率为100%,对广西黑山羊的保护率为80%.实验表明,山羊痘灭活疫苗对山羊的免疫效果确实可靠.     

Regional variations in the nematode worm populations of breeding ewes in New Zealand

AIM: To determine whether the generic composition of nematode parasites in lactating ewes varies between geographic regions in New Zealand and whether age and fecundity of ewes affect nematode egg output. METHODS: Four ram breeding properties in each of the northern (NNI) and southern (SNI) North Island and the northern South Island (NSI) regions, together with six properties in the southern South Island (SSI) were investigated. Faecal samples were obtained on one occasion, 2-6 weeks after lambing, from at least 60 ewes on each property, stratified according to age and reproductive status. Nematode eggs were counted and coprocultures prepared to identify genera present. Information on the history of anthelmintic use on each property was also collected. RESULTS: Highest faecal egg counts (FEC) were observed from ewes in the NNI and SSI regions. Lambed hoggets and twin-rearing two-tooth ewes had higher FEC than their unlambed or single-lamb-rearing contemporaries, respectively. However, no significant effect of reproductive effort on FEC was demonstrated in mixed-aged ewes. Significant regional differences in generic composition of nematode parasites were observed: Teladorsagia spp (also referred to as Ostertagia spp) eggs made up 56% of total eggs shed from sheep in the SSI compared with14% in the NNI, and values for Haemonchus spp were 1%and 24% for these same regions, respectively. Trichostrongylus colubriformis and T. vitrinus together made up 7, 15, 13 and15% of eggs counted from sheep in the SSI, NSI, SNI and NNI, respectively. CONCLUSIONS: More comprehensive epidemiological information may suggest regional-specific approaches to the management of nematode parasites in ewes should be devised in the future.     

骨顶鸡消化系统的解剖

通过观察描述骨项鸡消化系统各器官的解剖学特点,并与水禽、松鸡、雉鸡等的消化器官进行比较,发现与水禽相似,骨项鸡无嗉囊。骨顶鸡小肠占肠道总长的70％,盲肠占肠道总长的14％,松鸡科小肠占肠道总长的45％～49％,畜肠占肠道总长46％～49％,雉鸡小肠占肠道总长71％,盲肠占24％；从这些数据可以看出,骨项鸡小肠占肠道总长的比例居中,但盲肠短。