水杨酸对陈化马铃薯切片交替途径活性的诱导作用

在马铃薯切片陈化过程中,总呼吸速率（Ｖｔ）和交替途径容量（Ｖａｌｔ）分别升高了５倍和２８倍,但交替途径在无ＫＣＮ存在下几乎不运行。用２０μｍｏｌ／Ｌ的水杨酸处理陈化切片可引起总呼吸速率和交替途径容量的少量增加,但交替途径的运行却明显加强。水杨酸的这种促进作用在Ｐｅｒｃｏｌｌ纯化的线粒体中也有出现。马铃薯切片中交替途径运行的增加导致了线粒体呼吸控制比及ＡＤＰ／Ｏ的下降。这些都表明水杨酸对马铃薯切片陈化过程中抗氰交替途径的活性具有诱导作用。     

甘肃黄花烟草愈伤组织在生长与衰老期间呼吸途径的动态变化

实验结果表明：烟划愈伤组织在生长和衰老期间,总呼吸速率（Ｖｔ）分别在１１ｄ和１９ｄ出现２次呼吸跃升;细胞色素途径的运行（ρ＇Ｖｃｙｔ）与Ｖｔ的变化几乎一致,表明细胞色素途径仍组织主要的电子传递途径;交替途径容量（Ｖａｌｔ）及其与Ｖｔ的比值（Ｖａｌｔ／Ｖｔ）：在１５ｄ前不断上升,而在１５－１９ｄ之间处于稳定水平后下降。交替途径运行（ρＶａｌｔ）及其对Ｖｔ的贡献（ρＶａｌｔ／Ｖｔ）却与Ｖａｌｔ变化趋势     

甘肃黄花烟草愈伤组织抗氰呼吸的研究

根据呼吸抑制剂试验和氧肟酸滴定法测定结果表明,甘肃黄花烟草愈伤组织呼吸中有明显的抗氰交替途径运行,平均占总呼吸的31%;但仍以细胞色素途径为主,平均占总呼吸的46%;还有23%不受 KCN 加 m-CLAM 抑制的未知剩余呼吸。改变培养基的激素成分和浓度,在不引起愈伤组织发生明显分化条件下,愈伤组织的生长和呼吸速率虽有不同,但抗氰交替途径和细胞色素途径对总呼吸的相对贡献程度和二者的变化趋势基本一致。     

低温胁迫下甘肃黄花烟草愈伤组织的抗氰呼吸

继代培养的ｉｃｏｔｉｏｎｏ ｒｕｓｉｔｏａ Ｌ．ｃｖ．Ｇａｎｓｕ Ｙｅｌｌｏｗ Ｆｌｏｗｅｒ）愈伤组织经低温（４℃）处理后,交替途径容量９Ｖａｌｔ）和实际运行量（ρＶａｈ）均被显著地诱导,同时其电子传递途径也在发生交替变化。低温胁迫开始时以细胞色素途径为主,至第２天时则以交替途径为主,并一直持续到第５天,以后则又转为经细胞色素途径为主,而对照却始终以细胞色素途径为主。经放红菌酮或氯霉素处理后,受低     

毛花猕猴桃原生质体再生植株

从毛花猕猴桃（Ａｃｔｉｎｉｄｉａ ｅｒｉａｎｔｈａ Ｂｅｎｔｈ．）试管培养的实生苗新展开叶片分离的原生质体,培养在液体ＭＳ（除去ＮＨ４ＮＯ３）附加２,４－Ｄ １．０ ｍ ｇ／Ｌ和葡萄糖０．４ ｍ ｏｌ／Ｌ的培养基上。培养３周后植板率达到１９．４％ 。在未添加新鲜培养基的情况下,原生质体再生的细胞可持续分裂,并于３个月时长成２ ｍ ｍ 大小的愈伤组织。将该愈伤组织转移到附加玉米素０．５ ｍ ｇ／Ｌ和ＩＡＡ ０．１ ｍ ｇ／Ｌ的固体ＭＳ培养基上,分化出苗。试管苗经诱导生根,长成完整小植株     

柳叶烟草愈伤组织分化期间抗氰呼吸的改变

继代培养的柳叶烟草愈伤组织有明显的抗氰呼吸。交替途径的相对贡献约占总呼吸的29—38%;但仍以细胞色素途径为主,约占总呼吸的44—51%。接种在分化培养基上的愈伤组织在发生组织分化和芽原基形成期间,交替途径运行量占总呼吸的41—47%,承担呼吸电子传递的主要部分;而细胞色素途径只占总呼吸的29—32%。交替途径运行程度的增高可能与烟草愈伤组织的分化有一定相关性。     

苹果的抗氰呼吸与果实呼吸跃变的关系

苹果在发育期间呼吸对ＫＣＮ敏感,进入跃变期时呼吸为ＫＣＮ不敏感,但对间氯苯氧肟酸（ＣＬＡＭ）敏感。跃变期的苹果切片陈化后有诱导呼吸发生,且ＫＣＮ与ＣＬＡＭ对诱导呼吸都有一定的抑制作用。当在ＣＬＡＭ存在下进行陈化时,苹果诱导呼吸的发生被抑制约３０％,跃变期果实的特点是当果实进入成熟期时呼吸途径发生了由细胞色素途径向抗氰的交替途经转移的现象;同时其果实切片在陈化后可以发生诱导呼吸。     

菜心下胚轴原生质体培养和植株再生

以萌发３—４ 天（长约４ ｃｍ ）的菜心（Ｂｒａｓｓｉｃａ ｃａｍｐｅｓｔｒｉｓ ｖａｒ．ｐａｒａｃｈｉｎｅｓｉｓ）无菌苗苍白下胚轴为材料,酶解分离原生质体。经纯化的原生质体,在含０．５ ｍ ｇ／ＬＺＴ、０．５ ｍ ｇ／Ｌ２,４－Ｄ、１．０ ｍ ｇ／ＬＮＡＡ 和０．４ ｍ ｏｌ／Ｌ葡萄糖的Ｋ８ｐ 培养基中,进行微滴培养。在起始培养１４—１８小时,原生质体再生新的细胞壁。３６ 小时再生细胞开始第一次分裂。第三天分裂细胞频率可达３５％ 。培养第８—９ 天,可见含８—１６个细胞的小细胞团,植板率为１５％ —１８％ 。３ 周后将发育成直径为２ ｍ ｍ 的白色小愈伤组织,转到含０．３ ｍ ｇ／Ｌ ２,４－Ｄ并用ｇｅｌｒｉｔｅ半固化的培养基上,增殖成４—５ ｍ ｍ 直径的愈伤组织。在ＭＳ＋ ３．２（或１．６） ｍ ｇ／Ｌ ＢＡ＋ １．６（或０．８） ｍ ｇ／ＬＺＴ＋ ０．０１ ｍ ｇ／Ｌ ＮＡＡ＋ ０．１ ｍ ｇ／ＬＧＡ３ 和０．２％ 蔗糖的分化培养基上,获得芽的分化。切下约２ ｃｍ 长的芽苗,转移到含０．２ ｍ ｇ／ＬＩＡＡ 和２％ 蔗糖的培养基上,生根形成完整植株     

烟草愈伤组织继代培养期间呼吸途径与活性氧水平动态变化

继代培养期间的烟草愈伤组织总呼吸速率分别在第11天和第19天出现两次跃升,同时抗氰呼吸的发生与运行逐渐加强,在两呼吸高峰之间达到极大值,随后则逐渐下降,但愈伤组织的电子传递仍以细胞色素途径为主．通过对愈伤组织衰老过程中活性氧代谢变化分析,发现抗氰呼吸发生与H     

马铃薯块茎切片伤诱导抗氰呼吸的研究

马铃薯块茎新鲜切片呼吸中不存在抗氰的交替途径。相反,陈化24小时切片的伤诱导呼吸不仅相当抗氰,而且在氰化物(CN~-)存在和不存在时都被间-氯苯氧肟酸(m-CLAM)抑制,证明有交替途径运行。据测定,在陈化切片伤诱导呼吸中,交替途径和细胞色素途径分别约占总呼吸的28%和54%。当受 CN~-抑制时,交替途径的最大运行量(V_(alt))大于实际运行量(ρ·V_(alt)),表明电子流可能从细胞色素主路转向交替途径。当用碘乙酸和丙二酸抑制以降低陈化切片呼吸流时,KCN 和 m-CLAM 各自抑制呼吸的百分比并无改变,说明关于电子流量是控制交替途径“开关”的看法还不能完全得到证实。     

Effects of KCN and NaN3 Pretreatment on the Cyanide-Resistant Respiration in Tobacco Callus

The effects of KCN (0.5mmol/L) and NaN3 (0.01 mmol/L) pretreatment on the operation of the alternative pathway in subcultured tobacco (Nicotiana rustica L. cv. Gansu yellow flower) callus were analyzed. After treatment with KCN and NaN3 for 12 h, the total respiration rate (Vt) decreased by 12% and 17%, whereas oxygen consuption by the cytochrome pathway decreased by 22% and 28% respectively. The capacity of the alternative pathway (Valt) remained constant, while the activity of the alternative pathway (ρ· Valt ) inreased slightly. This changing pattern led to a declined contribution of the cytochrome pathway to the total respiration rate and an increased activity of the alternative pathway. Treatment with KCN for 24 h brought about a slight rise of oxygen consumption by the cytochrome pathway as compared with that in callus treated for 12 h, but the oxygen consumption was still lower than that in the untreated callus. Treatment with NaN3 for 24 h resulted in a profound decrease of the cytochrome pathway operation and a continuing increase of the alternative pathway operation. These data indicated that the enhanced operation of the alternative pathway played a compensatory role to the total respiration when the cytochrome pathway was partially inhibited in tobacco callus.     

Enhanced ethanol and chitosan production from wheat straw by Mucor indicus with minimal nutrient consumption

Recently, Mucor indicus was introduced as a promising ethanol producing microorganism for fermentation of lignocellulosic hydrolysates, showing a number of advantages over Saccharomyces cerevisiae. However, high nutrient requirement is the main drawback of the fungus in efficient ethanol production from lignocelluloses. In this study, application of fungal extract as a potential nutrient source replacing all required nutrients in fermentation of wheat straw by M. indicus was investigated. Wheat straw was pretreated with N-methylmorpholine-N-oxide (NMMO) at 120 °C for 1–5 h prior to enzymatic hydrolysis. Hydrolysis yield was improved at least by 6-fold for 3 h pretreated straw compared with that of untreated one. A fungal extract was produced by autolysis of M. indicus biomass, an unavoidable byproduct of fermentation. Maximum free amino nitrogen (2.04 g/L), phosphorus (1.50 g/L), and total nitrogen (4.47 g/L) as well as potassium, magnesium, and calcium in the fungal extract were obtained by autolysis of the biomass at 50 °C and pH 5.0. The fungal extract as a nutrient-rich supplement substituted yeast extract and all other required minerals in fermentation and enhanced the ethanol yield up to 92.1% of the theoretical yield. Besides, appreciate amounts of chitosan were produced as another valuable product of the autolysis.     

Biomass pretreatment strategies via control of rheological behavior of biomass suspensions and reactive twin screw extrusion processing

Twin screw extrusion based pretreatment of biomass is an attractive option due to its flexibility to carry out chemical reactions under relatively high stresses, temperatures and pressures. However, extrusion processes are rarely utilized in biomass pretreatment because such processing is constrained by rheological behavior of typical biomass suspensions. Without the manipulation of their rheological behavior, biomass suspensions become unprocessable within the extruder at modest biomass concentrations. Here it is demonstrated that gelation agents can render biomass suspensions processable. Specifically, carboxy methyl cellulose, CMC, could be used in conjunction with alkaline pretreatment of hardwood-type biomass and enabled separation of lignin from cellulose fibers. Furthermore, recycled black liquor, obtained upon pretreatment, was determined to be as effective as CMC for rendering biomass suspensions flowable by again facilitating the concomitant application of high shearing stresses and chemical treatment for the pretreatment of the biomass in the twin screw extruder.     

Addition of ammonia and/or oxygen to an ionic liquid for delignification of miscanthus

Ammonia and/or oxygen were used to enhance the delignification of miscanthus dissolved in 1-ethyl-3-methylimidazolium acetate at 140 °C. After dissolution of the gas at 9 bar, water was added as antisolvent to regenerate the dissolved biomass. In a next step, an acetone/water mixture was used to remove carbohydrate-free lignin from the regenerated biomass. The lignin content in the final product was around 10%, much lower than the ca. 23% lignin content of the raw dry miscanthus. This lignin reduction is achieved without diminution of cellulose or of total carbohydrates recovered, relative to the recovery achieved with the ionic liquid pretreatment in contact with air or nitrogen.     

提高黄皮种子活力的途径

黄皮种子经脱水至40％左右或持续贮藏（一年以上）后种子活力迅速下降,PEG对劣变种子直接引发不但不能提高其活力,反而使其活力更为下降,甚至丧失萌发能力而引发加速了代谢物质的消耗和渗漏。在黄皮种子脱水前用ABA、Ca2 、茶多酚（抗氧化剂）预处理,明显降低了黄皮种子的脱水敏感性。结合用PEG引发技术,则能较大幅度提高黄皮种子脱水后的活力,Ca2 短时高温引发也能提高黄皮种子贮藏一年后的活力,说明预处理是提高脱水和贮藏后黄皮种子活力的必要措施。     

低温和PEG预处理对小麦愈伤组织形成及IAA氧化的影响

研究了低温和ＰＥＧ预处理对小麦成熟胚愈伤组织形成及ＩＡＡ氧化的影响。结果表明,低温和ＰＥＧ预处理促进两种小麦成熟胚愈伤组织形成,但对其ＩＡＡ氧化的影响不同;其中低温引起‘郑引１号’ＩＡＡ氧化酶活性降低,但对‘保７０５９’的影响不大;而ＰＥＧ使‘保７０５９’的ＩＡＡ氧化酶活性增加,但对‘郑引１号’无明显影响;两种处理均使两种小麦ＩＡＡ过氧化物酶活性降低。     

鸟类组织稳定同位素分析样品的预处理方法

稳定同位素分析样品在进行同位素质谱分析之前需要适当的处理,然而如何处理尚未形成统一的标准。本文结合鸟类组织稳定同位素分析样品的测试流程,介绍了鸟类学研究领域稳定同位素技术应用中涉及的分析样品解冻清洗、干燥、分离纯化、研磨和储存等前处理方法,并对不同组织常用的处理方法及分析样品测定中有待解决的问题展开了讨论。旨在抛砖引玉,为利用稳定同位素技术开展鸟类学方面的研究提供科学参考和技术支持。     

The mechanisms of hydrothermal deconstruction of lignocellulose: New insights from thermal-analytical and complementary studies

Differential Scanning Calorimetry, Dynamic Mechanical Thermal Analysis, gravimetric and chemical techniques have been used to study hydrothermal reactions of straw biomass. Exothermic degradation initiates above 195 °C, due to breakdown of the xylose ring from hemicellulose, which may be similar to reactions occurring during the early stage pyrolysis of dry biomass, though activated at lower temperature through water mediation. The temperature and magnitude of the exotherm reduce with increasing acid concentration, suggesting a reduction in activation energy and a change in the balance of reaction pathways. The presence of xylan oligomers in auto-catalytic hydrolysates is believed to be due to a low rate constant rather than a specific reaction mechanism. The loss of the lignin glass transition indicates that the lignin phase is reorganised under high temperature auto-catalytic conditions, but remains partially intact under lower temperature acid-catalytic conditions. This shows that lignin degradation reactions are activated thermally but are not effectively catalysed by aqueous acid.     

Ethanol production from rice straw using optimized aqueous-ammonia soaking pretreatment and simultaneous saccharification and fermentation processes

Rice straw was pretreated using aqueous-ammonia solution at moderate temperatures to enable production of the maximum amount of fermentable sugars from enzymatic hydrolysis. The effects of various operating variables including pretreatment temperature, pretreatment time, the concentration of ammonia and the solid-to-liquid ratio on the degree of lignin removal and the enzymatic digestibility were optimized using response surface methodology. The optimal reaction conditions, which resulted in an enzymatic digestibility of 71.1%, were found to be 69 °C, 10 h and an ammonia concentration of 21% (w/w). The effects of different commercial cellulases and the additional effect of a non-cellulolytic enzyme, xylanase, were also evaluated. Additionally, simultaneous saccharification and fermentation was conducted with rice straw to assess the ethanol production yield and productivity.     

The effect of ultrasonication on enzymatic hydrolysis of chitin to N-acetyl glucosamine via sequential and simultaneous strategies

In this study, sequential and simultaneous strategies of ultrasonication (ultrasonic bath) were investigated to enhance enzymatic production of N-acetyl glucosamine (GlcNAc) from chitin powder. For the sequential strategy, the ultrasonic caused chitin powder to a visible fleecy structure, and Scanning electron microscopy (SEM) showed the surface of the treated chitin had a fiber-like structure with a diameter of 50 − 200 nm. Moreover, Fourier transform infrared spectroscopy (FTIR), Element analysis (EA), and X-ray diffraction (XRD) revealed that the crystallinity of the chitin decreased with little deacetylation. The simultaneous strategy is a one-pot treatment and enzymatic hydrolysis of chitin. The concentration of GlcNAc was 2.65 g/L for the strategy, which was 1.18- and 5.0-fold higher than the sequential strategy (2.25 g/L) and untreated chitin (0.53 g/L), respectively. In conclusion, this approach provided an efficient and environmentally friendly method for reducing the crystallinity of chitin and enhancing its enzymatic hydrolysis.