Changes in the glutathione thiol-disulfide status in wheat grain by foliar sulphur fertilization: consequences for the rheological properties of dough     

I. Tea  T. Genter  F. Violleau  D. Kleiber 《Journal of Cereal Science》2005,41(3):305-315

Storage proteins and glutathione in wheat play an important role in gluten network formation and can be modified by supplementation of nitrogen (N) and sulphur (S) in wheat plants. The glutathione thiol-disulfide status and its relationship to the molecular weight distribution wheat polymeric protein and dough rheological properties have been examined after different foliar S fertilizations (S derived from micronized elemental S and NS, a mixture of N urea and elemental S) applied at the post-anthesis stage. Changes in levels of reduced glutathione (GSH), glutathione disulfide (GSSG), polymeric protein-glutathione mixed disulfide (PPSSG) were analysed by reversed phase high performance liquid chromatography, during grain development using the wheat cultivars, Soissons and Trémie. During the grain desiccation phase, S supplementation (i) increased the GSSG/GSH ratio by 23–25% (ii) induced PPSSG accumulation, and (iii) decreased the formation of SDS-unextractable polymeric protein (UPP) and its molecular mass distribution. However, simultaneous N and S supplementation results in: (i) a decrease in PPSSG formation by 20–30% and (ii) an increase of UPP by 7–18% by enhancing both the branching of the aggregated proteins and their molecular weight. The mixograph parameters show that all forms of endogenous glutathione are linked to dough weakening and are negatively correlated with dough mixing tolerance, dough strength and consistency, while UPP is positively correlated with dough strength and consistency. These findings indicate that S nutrition influences dynamics of the glutathione forms in the grain and results in modification the degree of polymerization of storage protein. Thus both the changes in the form of glutathione and protein polymerization influence the rheological properties of dough.  相似文献   

一种新颖的阳离子非病毒基因载体 Chitosan-g-PEI-g-PEG-OH 的性能研究     

向建南  吴运东  王风君  梁志武 《湖南农业大学学报(自然科学版)》2013,40(12):74-79

研究了新型阳离子聚合物Chitosan-g-PEI-g-PEG-OH的性能，重点考察其粒度，基因转染效率与细胞毒性，探讨了其作为基因载体的可能性.通过动态光散射仪（DSL）、透射电镜（TEM）观察了Chitosan-g-PEI-g-PEG-OH与DNA自组装形成的颗粒形态及粒径，Chitosan-g-PEI-g-PEG-OH可复合DNA形成粒径160～210 nm的纳米复合物，适合进入细胞.使用MTT比色法分析Chitosan-g-PEI-g-PEG-OH的毒性并与PEI，PEI-g-PEG-OH比较.选用增强型绿色荧光蛋白(EGFP) 转染Hela细胞，应用流式细胞术检测转染效率.新型阳离子多聚物Chitosan-g-PEI-g-PEG-OH在提高基因转染效率的同时降低了其细胞毒性，有望成为基因转移的有效载体.  相似文献   

Impact of variation in structure of condensed tannins from sainfoin (Onobrychis viciifolia) on in vitro ruminal methane production and fermentation characteristics          下载免费PDF全文

B. Hatew  E. Stringano  I. Mueller‐Harvey  W. H. Hendriks  C. Hayot Carbonero  L. M. J. Smith  W. F. Pellikaan 《Journal of animal physiology and animal nutrition》2016,100(2):348-360

Our study investigated the effects of condensed tannins (CT) on rumen in vitro methane (CH₄) production and fermentation characteristics by incubating lucerne in buffered rumen fluid in combination with different CT extracts at 0 (control), 40, 80 and 120 g CT/kg of substrate DM. Condensed tannins were extracted from four sainfoin accessions: Rees ‘A’, CPI63763, Cotswold Common and CPI63767. Gas production (GP) was measured using a fully automated GP apparatus with CH₄ measured at distinct time points. Condensed tannins differed substantially in terms of polymer size and varied from 13 (Rees ‘A’) to 73 (CPI63767) mean degree of polymerization, but had relatively similar characteristics in terms of CT content, procyanidin: prodelphinidin (PC: PD) and cis:trans ratios. Compared to control, addition of CT from CPI63767 and CPI63763 at 80 and 120 g CT/kg of substrate DM reduced CH₄ by 43% and 65%, and by 23% and 57%, respectively, after 24‐h incubation. Similarly, CT from Rees ‘A’ and Cotswold Common reduced CH₄ by 26% and 46%, and by 28% and 46% respectively. Addition of increasing level of CT linearly reduced the maximum rates of GP and CH₄ production, and the estimated in vitro organic matter digestibility. There was a negative linear and quadratic (p < 0.01) relation between CT concentration and total volatile fatty acid (VFA) production. Inclusion of 80 and 120 g CT/kg of substrate DM reduced (p < 0.001) branched‐chain VFA production and acetate: propionate ratio and was lowest for CPI63767. A decrease in proteolytic activity as indirectly shown by a change in VFA composition favouring a shift towards propionate and reduction in branched‐chain VFA production varied with type of CT and was highest for CPI63767. In conclusion, these results suggest that tannin polymer size is an important factor affecting in vitro CH₄ production which may be linked to the CT interaction with dietary substrate or microbial cells.  相似文献   

抗旱保水剂在岗坡旱地甘薯上的应用试验     

杨英华  郭亚辉 《安徽农业科学》2007,35(29):9250-9250,9310

为提高冀南地区岗坡旱地农作物产量,应用抗旱保水剂在甘薯上进行了试验。结果表明,施用抗旱保水剂可提高甘薯幼苗成活率,促进甘薯生长,增产增收,以45kg/hm2用量效果最好。  相似文献   

胞外多聚物在污泥颗粒化过程中的作用研究   总被引：6，自引：1，他引：6  

竺建荣  胡贵平 《中国沼气》1993,11(3):5-10

本文研究了胞外多聚物(ECP)在污泥颗粒化过程中的作用。试验采用小试UASB反应器,以人工葡萄糖配水作为进料。测定结果表明,在颗粒污泥培养过程中,随着颗粒污泥的形成、生长和成熟,污泥ECP含量逐渐下降,从开始的6.36减小到30mg/gVSS。当反应器酸化、污泥性能变差或运行不稳定时,ECP含量则表现为急剧上升,达70mg/gVSS。这些结果说明污泥颗粒化过程中ECP所起的作用不大。对有关ECP的影响及作用机理,以及污泥颗粒化机制,文章进行了分析讨论。  相似文献   

抗旱保水剂应用特性的实验研究   总被引：1，自引：0，他引：1  

董建伟  王丽秋  胡燕玲 《中国农村水利水电》2002,(2):44-46

应用抗旱保水剂是近年来发展较快的一种非工程节水灌溉措施，在实际应用中，土、肥、水等多种因素对保水剂持水能力有很大影响。通过大量试验，对保水剂在各种应用条件下的持水特性进行了定性研究，提出了应用保水剂应注意的问题及若干建议。  相似文献   

介电型电活性聚合物能量收集方法研究   总被引：1，自引：0，他引：1  

朱银龙  王化明  周宏平 《农业机械学报》2015,46(9):362-367

介电型电活性聚合物(DEAP)作为一种新型智能材料,与风力、水力相结合,可作为一种新的能量收集方法。研究DEAP能量收集的可行性,讨论了DEAP的发电机理和工作过程。根据换能器工作状态的形变过程,利用弹性大变形理论建立了DEAP换能器的数学模型,通过对模型的求解计算出换能器推程、回程的力-位移曲线。据此,得出DEAP换能单元工作过程输入的机械能、发电量和相应能量转换效率。提出了一种多换能器集成使用以提高系统发电效率的方法。理论分析和试验数据表明:初始电压和拉伸位移是影响发电量、能量转换效率的关键因素。随着多换能单元的应用,系统的总效率可提高到28%以上。同时,外界输入扭矩的数值波动越来越小。  相似文献   

聚松香丙烯醇酯及其氧化物的合成及表征(Ⅰ)——微波加热法合成聚松香丙烯醇酯   总被引：8，自引：1，他引：7  

张晓丽  雷福厚  段文贵  李通耀  安鑫南 《林产化学与工业》2006,26(3):31-36

采用微波加热和常规加热方法聚合得到聚松香丙烯醇酯,分别对聚合物进行了红外、紫外、软化点和热失重分析。结果表明,微波加热聚合得到聚松香丙烯醇酯具有交联结构,松香的共轭双键参与了反应,软化点在300℃以上,微波加热反应的聚松香丙烯醇酯的相对分子质量在29 305以上,常规加热方法聚合得到聚松香丙烯醇酯相对分子质量在3 910以上,常规加热方法聚合时加入交联剂后得到的聚合物,相对分子质量在9 729以上,聚合物中残留有更多的双键,聚合物的热稳定性减弱。采用微波加热合成聚松香丙烯醇酯快速简便,聚合物性能优于常规方法。  相似文献   

不同抗旱措施配施菌肥对河西绿洲土壤改良和制种玉米产量的影响   总被引：1，自引：0，他引：1  

肖让  张永玲  赵芸晨  郭世乾  崔增团  师伟杰  吴克倩  俞海英 《水土保持学报》2021,35(3):341-349

为探讨地膜覆盖和施用保水剂配施菌肥后河西绿洲土壤微生物数量、酶活性变化及制种玉米产量和水分利用效率的影响,在河西走廊绿洲灌区设置单地膜覆盖(AF)、单施保水剂(AW)、单施菌肥(AB)、保水剂配施菌肥(WB)、地膜覆盖配施菌肥(FB)、露地不施保水剂和菌肥(CK)6个处理,分析制种玉米播种前和收获后0—20,20—40 cm土壤微生物数量及酶活性动态变化和产量变化。结果表明:(1)菌肥单施或配施均可提高土壤过氧化氢酶、脲酶、蔗糖酶、磷酸酶活性和增加真菌、细菌、放线菌数量及土壤微生物碳氮含量,改善土壤微生物环境,其中保水剂配施菌肥处理改善效果最佳,其次为地膜配施菌肥处理。(2)菌肥单施对制种玉米生长影响较小,但地膜配施菌肥可显著提高制种玉米叶面积指数和干物质积累量,并能调节产量构成因子。(3)不同抗旱措施及其配施菌肥能够不同程度促进制种玉米籽粒产量形成,其中地膜配施菌肥制种玉米籽粒产量最高(10 105.64 kg/hm~2),其次为单地膜覆盖(8 967.24 kg/hm~2)和保水剂配施菌肥(8 323.93 kg/hm~2),分别较CK显著增产61.99%,43.74%,33.43%。(4)地膜配施菌肥制种玉米水分利用效率最高(2.40 kg/m~3),其次为单地膜覆盖(2.15 kg/m~3)和保水剂配施菌肥(1.89 kg/m~3),分别较CK显著提高80.10%,61.84%,41.80%。因此,综合考虑产量、水分生产效率及土壤微环境等指标,抗旱措施配施菌肥最佳组合方式为地膜配施菌肥,既能促进制种玉米的生长发育,又能提高灌溉水利用效率和水分利用效率,在增产的同时,还能改善耕作层土壤微环境,对河西灌区制种玉米可持续发展具有重要的意义。  相似文献   

供水吸力、保水材料对番茄生长和产量的影响     

张伟娟  薛绪掌  胡跃高  李邵  张敏  陈菲 《灌溉排水学报》2010,29(6)

在温室条件下,采用负水头供水控水装置来持续稳定的控制土壤水分条件,采用裂区设计,研究了在供水吸力分别为4、7、10 kPa三种水分梯度下,2种保水材料(硅藻土、保水剂)对番茄产量与水分利用效率的影响。结果表明,随着供水吸力的增加,土壤质量含水率、光合速率、蒸腾速率、番茄的产量、干物质质量、植株耗水量均呈现出逐渐减小的趋势;在高土壤水分W1(4 kPa)条件下,保水剂(B3)的各项测定指标与其他处理的差异不大,但是在低土壤水分W2(7 kPa)、W3(10 kPa)或干旱的条件下,保水剂(B3)的土壤含水率、植株生长速率、光合速率、蒸腾速率、地上和地下部干物质质量、产量、耗水量、水分利用效率均显著低于CK(B1)和硅藻土(B2)。  相似文献