不同生物菌剂对大豆根系抗性物质的影响

在田间试验条件下,开展了4种生物菌剂拌种对大豆根系抗性物质影响的研究.结果表明,随着生育进程的推进,4种生物菌剂提高了根系中过氧化物酶和多酚氧化酶活性.在子叶期～一出复叶期,Y2(芽孢杆菌与木霉为主)处理对过氧化物酶和多酚氧化酶活性作用最强;在三节期～盛荚期,Y1(丛枝菌根真菌为主)处理对过氧化物酶和多酚氧化酶活性作用最强,Y2处理次之.另一方面,4种生物菌剂不同程度地减缓了丙二醛和脯氨酸含量的升高.在子叶期～三节期,Y1和Y2处理明显减缓了丙二醛和脯氨酸含量的升高,Y3(芽孢杆菌为主)和Y4(木霉为主)处理次之.此外,4种生物菌剂在一定程度上还促进了根系中可溶性糖的积累,但差异不大.综合分析表明,Y1和Y2拌种,可调节根系内抗性相关物质的生理功能,提高籽粒产量.     

云南省烟梗微波膨胀后致香物质差异性分析

采用微波膨胀技术处理云南省典型烟区烟梗,将微波处理和未用微波处理的烟梗均按常规工艺制成梗丝,分别测定了2种梗丝中致香成分的相对含量,检测出了8类77种致香物质,并对比分析了各种致香物质在处理前后的变化及其对感官评吸质量的影响。结果表明,微波处理烟梗制成的梗丝与常规梗丝相比,醇类和酯类致香物质相对含量无显著性差异;酚类和烯烃类相对含量有显著差异,变化量分别为-10.98%和10.33%;醛类、酮类、酸类和杂环类相对含量存在极显著差异,微波处理后其相对含量分别增加了27.54%、12.99%、39.15%和30.83%;烟梗经微波处理后感官品质明显改善。     

自然越冬过程中不同杨树品种的抗寒生理指标分析

试验以银×新、北美速生杨1号、抗虫杨、抗盐碱杨4种杨树(Populus L.)的一年生扦插苗为试验材料,探讨自然条件下,不同杨树品种抗寒生理、生化指标的变化及与抗寒性的关系。结果表明,在相同立地条件下,不同品种杨树的抗寒生理指标表现出差异;渗透调节物质可溶性糖、可溶性蛋白质含量和短时的降温相关不密切,杨树应对低温能力较强,渗透调节系统稳定,具有较强的渗透调节能力;保护酶活性与温度密切相关,丙二醛含量随温度的变化而呈规律性变化。自然条件下,各抗寒生理指标随气温的变化呈规律性变化,各杨树品种的抗寒性差异显著。     

毛竹笋呈味物质种类、含量与辛辣味强度的关系

[目的]对3种类型毛竹笋进行品尝和分析,探索毛竹笋辛辣味的呈味物质,为提高毛竹笋食用品质和经济价值提供参考。[方法]试验运用感官评定、气质联用(GC-MS)、高效液相色谱(HPLC)等方法,对出土毛竹笋(AS)、未出土毛竹笋(US)和毛竹鞭笋(RS)3种新鲜竹笋及AS竹笋水煮后的笋渣、笋汤进行感官评定、成分分析,开展呈味物质含量与相应滋味强度的相关性分析。[结果](1)经感官评定,AS和US 2种类型毛竹笋辛辣味均表现为从笋基部到笋尖依次增强的趋势,而AS竹笋从笋基部到笋尖辛辣味强度值为2.0 9.5,明显高于US的1 6,RS竹笋滋味则表现为微甜,笋基部到笋尖无明显变化。AS竹笋水煮后笋渣滋味为辛辣味,且辛辣味强度随水煮时间的延长而降低;笋汤滋味则表现为苦涩味,滋味强度随水煮时间的延长而增强。(2)通过GC-MS方法,共检测出毛竹鲜笋43种成分,其中,酯类9种、醇类6种、酸类5种、酚类3种、酮类2种、醛类3种、烃类4种和其它11种,其中,相对含量较高且与辛辣味有关的物质为草酸、单宁和麻黄碱。(3)相关性分析表明,与AS和US竹笋辛辣味显著相关的呈味物质为氰化物、氰苷、单宁和麻黄碱,与AS竹笋辛辣味强度的相关系数分别为0.812、0.850、0.939、0.818(P0.01);与US竹笋辛辣味强度的相关系数分别为0.905、0.857、0.939、0.937(P0.01)。AS水煮后笋渣中氰化物、氰苷和单宁与辛辣味强度显著相关,相关系数分别为0.859、0.861、0.933(P0.01),笋汤中与苦涩味强度显著相关的有氰化物、单宁和草酸,相关系数分别为0.982、0.954、0.976(P0.01)。综合表明:毛竹笋辛辣味的呈味物质是氰化物、氰苷和单宁。[结论]影响毛竹笋辛辣味的主要呈味物质为氰化物、氰苷和单宁,其辛辣味是三者相互作用的结果。     

Animal and forage responses on Maximus,a tetraploid cultivar vs Marshall,a diploid cultivar of annual ryegrass

This 2‐year grazing study carried out at Raymond, Mississippi, USA, evaluated animal performance and forage characteristics of a tetraploid (“Maximus”) vs a diploid cultivar (“Marshall”) of annual ryegrass at three stocking rates (SR; 3.5, 5.0 or 7.5 animals per ha). Angus cross‐bred heifers (Bos taurus; initial body weight [BW] = 240 kg) were continuously stocked on pastures at set stocking rates for the duration of the study. Stocking rates and cultivars were arranged in a 3 × 2 factorial design that was completely randomized with two replications. There was no cultivar effect (p = .449) on average annual herbage mass (HM). However, HM decreased linearly with increasing SR (p = .001) from 3.8 to 2.5 t ha^?1 during Year 1 and 4.4 to 3.8 t ha^?1 during Year 2 (p = .028). In Year 2, there was a difference in water‐soluble carbohydrates (WSC) between cultivars (p = .012; Marshall, 117.0 vs Maximus, 139.0 g/kg). There was no cultivar effect (p > .10) on average daily gain (ADG) in either year of the study. In both years, ADG decreased linearly with increasing SR (p = .001) from 1.22 to 0.98 kg/d during Year 1 and 1.31 to 1.08 kg/d during Year 2. Across years, gain ha^?1 increased linearly (p < .001) with increasing SR. Our results showed no difference in animal performance and HM between the two cultivars. Producers’ choice of annual ryegrass cultivar should be based on seeding cost and agronomic traits that allow for better adaptation of the forage.     

Effects of Lactobacillus buchneri as a silage inoculant and as a probiotic on feed intake,apparent digestibility and ruminal fermentation and microbiology in wethers fed low‐dry‐matter whole‐crop maize silage

Lactobacillus buchneri was investigated as a silage inoculant and as a probiotic on feed intake, apparent digestibility, and ruminal fermentation and microbiology in wethers fed low‐dry‐matter (DM) whole‐crop maize silage. Maize forage (279 g/kg DM) was ensiled without inoculant (untreated) and with L. buchneri CNCM I‐4323 at 1 × 10⁵ cfu/g fresh forage (inoculated). Six cannulated wethers were arranged in a double 3 × 3 Latin square and assigned to one of three diets: (i) untreated maize silage (untreated), (ii) inoculated maize silage (inoculated), and (iii) untreated maize silage with a daily dose of L. buchneri (1 × 10⁷ cfu/g supplied silage) injected directly into the rumen (LB‐probiotic). Wethers fed the inoculated diet had a higher (p = .050) DM intake (1.30% body weight [BW]) than wethers fed untreated and LB‐probiotic diets (1.17% and 1.18% BW respectively). The relative proportion of Ruminococcus flavefaciens (proportion of total estimated rumen bacterial 16S rDNA) in the rumen of wethers fed inoculated and LB‐probiotic diets (both 0.42%) tended (p = .098) to be lower than in the untreated diet (0.83%). Lactobacillus buchneri as a silage inoculant or as a probiotic had little effect on the variables measured in wethers.     

不同辣木种质资源叶片营养元素含量分析

对引进的32份辣木种质资源叶片的N、P、K、Ca等营养元素的含量进行测定分析。结果表明:辣木叶片中N元素含量最高,其含量在3 600.53~5 093.73 mg/hg之间,其次是K元素含量,其含量在583.01~1 034.83 mg/hg之间。辣木种质资源成熟叶粉营养元素含量总体呈现N>K>P>Mg>Ca>Mn>Zn>Fe>Cu的趋势。相关分析结果显示,Fe元素含量与N元素含量之间呈极显著正相关,相关系数达0.526,此外,Fe元素含量与除了P元素之外的其他元素含量均显著相关,而P元素含量与其他任何元素含量之间的相关性均不显著。聚类分析结果显示,利用N元素含量的差异,32份辣木种质资源被分成来自于非洲的A类群和来自于亚洲国家或地区的B类群。      

AM真菌对连作作物根系代谢产物的影响

摘 要：近年来,连作问题一直危害着作物的产量和品质。大量研究证明,丛枝菌根(Arbuscular mycorrhizal,AM)真菌与作物根系形成共生的菌根并通过分泌次级代谢产物抵抗外界环境所带来的侵害。为了探究AM真菌在作物调节次级代谢产物中扮演的角色和作用机理,总结了AM真菌增加次级代谢产物种类及含量、诱导信号物质产生（如JA、SA等）和缓解连作障碍的作用机制,同时也揭示了化感作用与次级代谢之间的关系。并从代谢水平指出了AM真菌对作物分泌次级代谢产物的影响,以及AM真菌在抗连作方面的作用机理,以期为AM真菌在农业生产上的应用提供有价值的信息。     

拮抗灰霉菌的海洋细菌甲基营养型芽胞杆菌的筛选、鉴定及其抑菌活性物质的研究

采用Zo Bell’s 2216E培养基从65份渤海海水和底泥样品中分离到海洋细菌464株,通过平板对峙法获得了对灰霉菌具有较强拮抗作用的海洋细菌47株,其中菌株BH21的抑菌作用最强,抑菌带宽度为(11.8±0.3)mm;采用形态学、生理生化和分子生物学相结合的方法,将菌株BH21鉴定为甲基营养型芽胞杆菌Bacillus methylotrophicus,该菌具有较强耐盐、耐甲醇能力;通过排油圈法确定菌株BH21能够产生具有表面活性的代谢产物,随后以脂肽类物质相关基因的特异序列为引物进行菌株BH21抑菌活性成分相关基因的扩增,确定该菌株中含有itu A、itu B、itu C、itu D、fen D、srf AB和ynd J等7种脂肽物质的合成基因;利用盐酸沉淀和甲醇抽提法获得了BH21发酵液中脂肽粗提物,通过牛津杯法确定该脂肽粗提物具有明显抑制灰霉菌菌丝生长的能力,抑制率达到73.9%。     

高效降解游离棉酚并改善棉籽粕营养品质的菌株筛选

本试验旨在利用枯草芽孢杆菌和植物乳酸菌发酵棉籽粕,研究其对棉籽粕中游离棉酚降解率的影响,并对发酵前后棉籽粕的营养品质指标如活菌数、中性蛋白酶活性、酸溶蛋白质含量、pH、游离棉酚含量等进行比较。结果发现:可高效降解棉籽粕中游离棉酚的枯草芽孢杆菌菌株为BLCC1-0039,可有效改善发酵风味的植物乳酸菌菌株为BLCC2-0092。综合上述2株益生菌的优点,筛选出最优复配发酵方式为植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039按照1∶1比例接种,37℃需氧发酵24h再厌氧发酵。与空白对照组相比,最优复配发酵组各发酵阶段发酵棉籽粕的pH显著降低(P0.05),厌氧发酵72h时pH降至5.27;酸溶蛋白质含量显著提高(P0.05),厌氧发酵72h时酸溶蛋白质含量达到23.54%;游离棉酚含量显著降低(P0.05),需氧发酵24h时游离棉酚降解率达到52.12%,厌氧发酵72h时游离棉酚降解率达到61.58%。由此可知,植物乳酸菌BLCC2-0092与枯草芽孢杆菌BLCC1-0039复配发酵可有效降低发酵棉籽粕中的游离棉酚含量并改善其营养品质。