外源水杨酸对水稻幼苗盐胁迫下生理效应的影响

研究了在盐胁迫条件下外源水杨酸(SA)对水稻幼苗耐受性应答的影响.本研究以水稻为材料,用1 mmol/L的外源水杨酸对水稻幼苗叶片进行喷雾处理,静置24 h后,经SA处理后的水稻幼苗再经过100 mmol/L的NaCl胁迫处理0-48 h.结果表明,经外源水杨酸处理的水稻幼苗,能显著增强体内脯氨酸(Pro)、可溶性蛋白的含量以及超氧化物歧化酶(SOD)、过氧化物酶(POD)等保护酶的活性,显著降低丙二醛(MDA)的含量.表明在盐胁迫条件下,外源水杨酸能增强水稻幼苗自身抗氧化系统中酶的活性,减轻和缓解盐胁迫带来的伤害.     

Enzymatic preparation of manno-oligosaccharides from locust bean gum and palm kernel cake,and investigations into its prebiotic activity

BackgroundManno-oligosaccharides (MOS) is known as a kind of prebiotics. Mannanase plays a key role for the degradation of mannan to produce MOS. In this study, the mannanases of glycoside hydrolase (GH) families 5 Man5HJ14 and GH26 ManAJB13 were employed to prepare MOS from locust bean gum (LBG) and palm kernel cake (PKC). The prebiotic activity and utilization of MOS were assessed in vitro using the probiotic Lactobacillus plantarum strain.ResultsGalactomannan from LBG was converted to MOS ranging in size from mannose up to mannoheptose by Man5HJ14 and ManAJB13. Mannoheptose was got from the hydrolysates produced by Man5HJ14, which mannohexaose was obtained from LBG hydrolyzed by ManAJB13. However, the same components of MOS ranging in size from mannose up to mannotetrose were observed between PKC hydrolyzed by the mannanases mentioned above. MOS stability was not affected by high-temperature and high-pressure condition at their natural pH. Based on in vitro growth study, all MOS from LBG and PKC was effective in promoting the growth of L. plantarum CICC 24202, with the strain preferring to use mannose to mannotriose, rather than above mannotetrose.ConclusionsThe effect of mannanases and mannan difference on MOS composition was studied. All of MOS hydrolysates showed the stability in adversity condition and prebiotic activity of L. plantarum, which would have potential application in the biotechnological applications.How to cite: Zhang R, Li X-Y, Cen X-L, et al. Enzymatic preparation of manno-oligosaccharides from locust bean gum and palm kernel cake, and investigations into its prebiotic activity. Electron J Biotechnol 2021;49. https://doi.org/10.1016/j.ejbt.2020.11.001     

从大豆中提取豆油实验方法及装置的改进

化学实验“从大豆中提取豆油”,原方法和装置不易操作,造成实验成功率低,且存在氯仿污染环境的问题。针对这一问题进行了改进,改进后的实验,学生易操作,重复性好,无污染,还能准确地测定豆油的含量。     

黑龙口豆腐干加工工艺优化研究

以感官评定结果为指标,通过正交试验研究了压榨时间、卤制次数、烘烤温度和烘烤时间对黑龙口豆腐干产品感官质量的影响,并对黑龙口豆腐干加工工艺进行优化。结果表明：压榨时间、卤制次数和烘烤温度对黑龙口豆腐干产品的组织状态具有显著影响,压榨时间、卤制次数和烘烤时间对黑龙口豆腐干产品的颜色外观具有极显著影响,在压榨90min、卤制3次、80℃烘烤4．5h的条件下,黑龙口豆腐干的产品总体感官质量最佳。     

新乡市豆芽中亚硝酸盐含量的测定

采用分光光度法对新乡市市售豆芽中亚硝酸盐的含量进行了随机采样检测。结果表明,在亚硝酸盐的量为0～12.5ug/50ml水溶液时与吸光度有良好的线性关系,其线性回归方程为A=0.016x＋0.003（r=0.9990）,该方法简便、快捷、灵敏、实用,可作为食品中亚硝酸盐含量的测定方法,利用此方法测定的样品中亚硝酸盐含量均未超过相关标准。     

设施无公害菜豆平衡施肥技术方案

通过对菜豆营养成分及其植物营养特性的分析,结合近年来菜豆施肥试验结果,提出了设施无公害菜豆平衡施肥技术方案.     

不同酸性条件下豆渣对Cd(Ⅱ)的吸附研究

研究了不同酸性条件下豆渣对水中Cd(II)的吸附特征.结果表明:(1)在强酸(pH=2.0)、中等酸性(pH=4.0)和弱酸(pH=6.0)条件下时豆渣对Cd(II)的最大吸附率分别为55.4%、99.2%和79.4%,中等酸性条件下豆渣对水中Cd(II)的吸附率最大.(2)豆渣对Cd(II)的吸附过程遵循F方程;而L方程对弱酸条件下的吸附过程拟合较好(R2>0.99).在中等酸性和弱酸条件下,豆渣吸附Cd(II)是向有利于吸附的方向进行的,而在强酸条件下则不利于吸附.     

邓拓对中国资本主义萌芽问题的研究

邓拓对中国资本主义萌芽问题的研究具有开拓性贡献。他的研究成果不多,但很丰硕,形成了成型的资本主义萌芽思想体系;他的研究理念和方法经常被后来研究者借鉴,形成了一定模式的学术理路。他对中国资本主义萌芽问题的研究,是中国社会经济史的重要组成部分。     

酸雨对不同农作物种子萌发的影响

实验采用不同pH的模拟酸雨,研究其对玉米和绿豆种子萌发的影响.结果表明:pH=2.0时,玉米和绿豆均不发芽;pH=2.5时,只有异状发芽;pH≥3.0时,二者的发芽率,发芽势、发芽指数、活力指数、贮藏物质的的消耗率与运转率均随pH值的上升而增大;异状发芽率、芽长和根长的抑制指数则随pH值的增大而降低;酸雨胁迫下,绿豆各项指标的变幅都小于玉米的结果,表明绿豆抗酸雨胁迫的能力比玉米强.     

Participatory Plant Breeding with Traders and Farmers for White Pea Bean in Ethiopia

Abstract

Purpose: This research, conducted in Ethiopia, involved select stakeholders in the variety evaluation process early: to identify a greater number of acceptable varieties and to shorten a lengthy research and release process.

Design/methodology/approach: A Participatory Plant Breeding (PPB) approach was used in both on-station and community-based trial evaluations. Farmers, traders and processors evaluated bean varieties for promotion, considering field performance, culinary characteristics, market value, and canning acceptability.

Findings: Within four years, two varieties were identified and recommended for release which were high performing, had excellent consumption and cooking characteristics for local foods, fetched high local market prices and met international canning quality standards.

Practical implications: (1) Ethiopian men and women have distinct criteria for evaluating white pea beans, the former putting emphasis on marketability, with women focusing on food security issues. Both groups might be involved in the selection process. (2) Key characteristics cited by farmers, for instance, use for forage, may not be taken into account in the formal breeding process. Expanding the criteria used to determine which varieties should be released would make economic sense. (3) Farmers screened for local product acceptability before researchers put forward lines for testing by the export and canning industry. Local acceptability need not necessarily conflict with market chain acceptability—if the right processes are followed.

Originality/value: The context was unusual: a) the region was drought-prone; and b) the crop had to meet rigorous canning requirements, plus local preferences. The involvement of traders and processors was novel, as was the use of a ‘participatory framework’ even when the product had to meet stringent market requirements.