宁夏枸杞叶片、果柄、果实糖积累与蔗糖代谢相关酶活性研究

对不同发育时期宁夏拘杞叶片、果柄、果实中蔗糖,果糖、葡萄糖含量及蔗糖代谢相关酶活性进行测定,研究枸杞叶片、果柄、果实生长发育过程中糖的积累与蔗糖代谢相关酶活性的关系.结果表明,宁夏枸杞叶片以积累蔗糖为主,果糖的含量与酸性转化酶(AI)和中性转化酶(NI)均旱显著正相关;果实以积累已糖(葡萄糖和果糖)为主,葡萄糖和果糖的含最与AI和NI均呈极显著正相关,而与其他酶无相关性,说明AI和NI在宁夏枸杞果实的糖代谢中起着主要的调控作用.     

乳饮料稳定性影响因素的研究

[目的]对乳饮料稳定性的影响因素进行分析和探讨。[方法]分别调整乳饮料中稳定剂、乳化剂、乳固形物、酸度等配比,测定其相应的稳定性。[结果]稳定剂使用量应依据酸性乳饮料中的乳固形物含量、糖酸比例,一般使用总量≤1．0％;HLB值不同的几种乳化剂混和使用．且混和后HLB值为8—13时效果较好;乳固形物含量越高,酸性乳饮料的稳定性越差（H值小）;乳饮料中蔗糖量越多,其稳定性越好;果汁和有机酸量增加,饮料酸度升高,稳定性相对降低。[结论]酸性乳饮料中的乳固形物含量为4．0％,海藻酸丙二醇酯0．3％,羧甲基纤维素0．2％,黄原胶0．1％,蔗糖酯0．04％,乳化剂B0．02％,单甘酯0．06％,蔗糖12．0％,果汁4．0％,有机酸0．2％,可以有效的解决乳饮料中乳蛋白发生分层和沉淀等问题。     

Alkali combined extrusion pretreatment of corn stover to enhance enzyme saccharification

Because of good adaptability, high throughput and continuous feature, twin-screw extrusion has been shown to be a promising pretreatment method for biomass to open the cell wall at the microscopic scale. This greatly increases the specific surface area for enzyme adsorption regardless of crystallinity. The objective of this study was to investigate the effectiveness of alkali-assisted extrusion for improving corn stover digestability. The glucose and xylose sugar yields for combined process were 86.8% and 50.5%, respectively, at an alkali loading of 0.04 g/g dry biomass, a screw speed of 80 rpm, temperature of 140 °C and washed with water. The average residence time for extrusion is 27 min for 100 g corn stover. These yields were 3.9 and 13.3 times higher than their untreated counterparters. The crystallinity index was not related with hydrolysis yields. Congo red dye adsorption indicated that alkali-assisted extrusion produced significantly more pores at the meso and large scales compared to untreated material, which significantly improved the sugar yields.     

红枫湖水库的污染现状及治理对策

概述了近年来红枫湖水质的变化情况及其污染的原因,介绍当前治理红枫湖污染的一些措施及治理过程中存在的问题,并据此提出治理红枫湖污染的部分建议。     

Artificial neural network analysis of lipase-catalyzed synthesis of sugar alcohol ester

Artificial neural network (ANN) analysis of immobilized Candida antarctica lipase B-catalyzed esterification of palmitic acid with xylitol was carried out. Temperature, time, amount of enzyme, amount of molecular sieve, substrate molar ratio and volume of solvent were the six important parameters used as the inputs of the network trained by Levenberg-Marquardt (LM) algorithm. After evaluating different ANN configurations, the best network was found to be consisted of two hidden layers with six and seven neurons in the first and second layers respectively, using a hyperbolic tangent sigmoid transfer function. The coefficient of determination (R²) and mean square error (MSE) values between the actual and predicted responses were 1 and 1.5025e−24 for the training and 0.97239 and 0.03259 for the testing datasets. The results indicate the good generalization performance of the neural network model and its capability to predict the conversion of the substrates.     

新形势下云南制糖业发展的思考

云南制糖业经过多年发展,已成为仅次于烟草的第二大农产品加工业,云南也已成为中国第二产糖大省。制糖业的发展关系到云南省600万蔗农的切身利益,发展好制糖业是解决云南省三农问题的有效途径之一。尽管取得了较大的发展成绩,但云南制糖业仍然存在甘蔗种植劳动力资源不足、优良品种研发和推广滞后、原料不能满足制糖生产需要、生产规模化程度低以及制糖企业经营规模小、技术装备存在差距的问题。在国家对云南实施“桥头堡”战略的新形势下,云南制糖业应把握好自身优势,抓住机遇,通过加大对制糖业的扶持,实行甘蔗种植产业化、规模化经营,进行结构调整,重视科技创新和加强人才队伍建设等措施,促进制糖业的健康发展。     

桂林沙糖桔花果期气象灾害分析

沙糖桔的产量与花果期气象条件密切相关,保花保果期气象灾害严重影响后期产量.为研究保花保果期气象灾害对桂林沙糖桔产业的影响,对桂林沙糖桔保花保果期气象灾害的天气防御措施进行分析和研究.桂林沙糖桔保花保果期指每年3～6月,沙糖桔开花及幼果生长期,此时的温度突升突降、雷雨大风、冰雹、暴雨等灾害会造成大量花朵或幼果脱落,树体伤害,挂果数量减少,产量下降.及时了解灾害天气信息,及时做好水肥管理,可以有效减少气象灾害带来的损失,保证沙糖桔优质丰产.     

Seed dormancy and soil seedbank of the invasive weed Chenopodium hybridum in north‐western China

Seed dormancy and persistence in the soil seedbank play a key role in timing of germination and seedling emergence of weeds; thus, knowledge of these traits is required for effective weed management. We investigated seed dormancy and seed persistence on/in soil of Chenopodium hybridum, an annual invasive weed in north‐western China. Fresh seeds are physiologically dormant. Sulphuric acid scarification, mechanical scarification and cold stratification significantly increased germination percentages, whereas dry storage and treatments with plant growth regulators or nitrate had no effect. Dormancy was alleviated by piercing the seed coat but not the pericarp. Pre‐treatment of seeds collected in 2012 and 2013 with sulphuric acid for 30 min increased germination from 0% to 66% and 62% respectively. Effect of cold stratification on seed germination varied with soil moisture content (MC) and duration of treatment; seeds stratified in soil with 12% MC for 2 months germinated to 39%. Burial duration, burial depth and their interaction had significant effects on seed dormancy and seed viability. Dormancy in fresh seeds was released from October to February, and seeds re‐entered dormancy in April. Seed viability decreased with time for seeds on the soil surface and for those buried at a depth of 5 cm, and 39% and 10%, respectively, were viable after 22 months. Thus, C. hybridum can form at least a short‐lived persistent soil seedbank.     

Stand dynamics and tree quality response to precommercial thinning in a northern hardwood forest of the Acadian forest region: 23 years of intermediate results

In the late 1980s, large forest companies began precommercial thinning (PCT) operations in young northern hardwood cutovers in New Brunswick, Canada. To provide supporting growth and yield information, an industrial experiment was established at residual stand densities of 1300, 1600, 1900, and 2200?stems?ha^?1. Stand responses were examined for measurements recorded at 0 (1987), 5 (1992), 10 (1997), 16 (2003), and 23 (2010) years after establishment. Average diameter at breast height, quadratic mean diameter, stand basal area, and stand total volume growth increased as stem density decreased from PCT. There were significant linear differences for many of these variables between treatments and time periods (year). No significant differences were detected in tree height between treatments. In 2010, the four PCT thinning treatments did not exhibit any differences in potential sawlogs at 2.4?m (8?ft) and 3.6?m (12?ft) lengths. Significant differences were observed for 4.9?m (16?ft) sawlogs that were produced at the least dense spacing (1300?stems?ha^?1). Results from this study and recommendations from the European literature suggest that value-added timber products may be produced from more intense PCT treatments than are currently being practiced on sites dominated by yellow birch (Betula alleghaniensis Britt.).     

果实糖分积累研究进展

基于果实糖分积累与果实发育及其品质密切相关性,综述了果实中糖分的生理功能、果实糖分积累的基因型差异、糖分积累与果实发育的关系以及糖代谢相关酶在果实糖分积累中的作用,以期为这一领域的深入研究提供依据。