Ecophysiological aspects of in vitro biotechnological studies using somatic embryogenesis of callus tissue toward protecting forest ecosystems

This review on current biotechnological methods in forestry for in vitro tissue cultures to define the effect of stress conditions on trees,concentrates on somatic embryogenesis.Callus tissue,the key product of somatic embryogenesis,grows over a tree wound under ex vitro conditions.Callus tissue can be used in research in areas such as pathogenic susceptibility at the embryonic level,effect of heavy metals,influence of low temperatures(cryopreservation),production of secondary metabolites and transformation of plants.Callus of arborescent plants can be induced in vitro by fungal elicitors to produce secondary metabolites for pharmaceutical and cosmetic industries and are strongly repellant to herbivores and can thus act to protect forests.Analyses of dual cultures demonstrated that callus tissue exposed to a pathogenic fungus responds by synthesizing low-molecular-mass proteins belonging to an immune protein class.Cryopreservation of embryonic callus tissue also has broad applications,e.g.,for valuable plant genotypes in gene banks.Without strategies to protect forests against stressfactors,forest ecosystems will degrade to the detriment of all life,including humans.In vitro biotechnological research using callus tissue contributes to progress in forestry and the disciplines of ecology,physiology,phytopathology,culture and selection of plants.     

皮锡瑞《经学家法讲义》稿本的内容及其价值

保存在《师伏堂经学杂记》中的一组经学文稿,是近代经学大师皮锡瑞晚年讲授"经学家法"课程时所编讲义原稿。这部《经学家法讲义》手稿对先秦至魏晋的经学变迁与得失作了简明扼要的疏理和评述,描绘出魏晋以前经学历史的基本轮廓,其中的新见卓识,更显示出这部隐秘至今的经学遗稿的学术价值。皮锡瑞还在稿中自道其"郑学"研究,有助于今人全面体认他融通今、古文经学的学术品性,确证他决非专治今文家言的经师。     

Effects of repeated metolachlor applications on its persistence in field soil and degradation kinetics in mixed microbial cultures

 The persistence of metolachlor, a soil-applied herbicide, was studied under field conditions involving repeated herbicide applications. The test field received four applications of metolachlor over an 8-month period, which included two cropping seasons. There was a trend for more rapid rates of degradation with increasing numbers of previous treatments, with fifty percent dissipation time (DT₅₀) of metolachlor declining from 18 days in the first spray to 2.5 days in the fourth spray. An effort was made to isolate the microbial population which had become acclimated to the herbicide from this field soil. A fungal community isolated from this soil showed the capacity to degrade up to 99.6% of the metolachlor within a span of 20 days. The bacterial community isolated could also degrade up to 81.5% of the metolachlor. Hence, this study clearly indicated that repeated applications of metolachlor to soil resulted in the generation of an adapted microbial population with an enhanced ability to degrade the applied herbicide. Received: 13 November 1998     

茶树体细胞植株再生的光照效应

为了探寻光照对茶树体细胞植株再生的影响效果,以茶树全胚,具有子叶柄的子叶为材料,研究５００,１５００ｌｘ,黑暗３种光照条件对植株再生的影响。结果表明,胚状体主要发生在子叶柄了子叶片的隆起处,子叶片隆起发生率随光照度增加而降低,子叶发生隆起的子叶培养物在５００ｌｘ光照度下培养,子叶片的胚状体分化率较高,子叶柄的胚状体,不定芽分化随光照度下降而下降;连续在黑暗下培养,子叶片的畸形胚发生率高,且数量多。     

Avian whole‐brain spheroid cultures: applications in pesticide toxicity

The adult hen is the species of choice when assessing the potential of organophosphate compounds (OPs) to evoke OP‐induced delayed neuropathy (OPIDN). OPIDN has been shown to depend on the irreversible covalent binding of certain OPs to the enzyme neuropathy target esterase (NTE). Levels of this enzyme in human brain are similar to those in avian species. We have previously shown that the hen embryo whole brain spheroids are histotypically similar to adult brain and express measurable levels of acetylcholine esterase (AChE) and NTE, the key enzymes in mechanisms of OP toxicity. Single‐cell suspensions were prepared from meninges‐free 7 day in ovo hen brains. Cells were grown in serum‐free media and incubated on an orbital shaker at 37 °C in 5% carbon dioxide humidified air. Spheroids can be maintained long‐term in culture and allow the effects of repeated dose and recovery studies to be conducted. Hen embryo brain spheroids were exposed to varying concentrations of tri‐o‐cresyl phosphate, leptophos and its metabolite leptophos oxon at day 14 in vitro and the effects on the activity of AChE and NTE measured. Whilst current legislation regarding toxicity testing of OPs requires the use of animals, our in vitro model provides a potential pre‐screen for novel chemical entities and commercial OP mixture variants. Such an approach should refine and reduce the number of animals used in development of new materials. © 2000 Society of Chemical Industry     

乳酸菌培养物对肉鸡生长性能及免疫功能的影响

试验旨在研究灭活乳酸菌培养物对肉鸡生长性能及免疫功能的影响。选择300只体重相近的健康1日龄AA肉仔鸡,随机分为5组,每组6个重复,每个重复10只鸡,雌、雄各半。其中对照组饲喂基础日粮,抗生素组在基础日粮中添加0.01%金霉素,乳酸菌培养物组分别在基础日粮中添加0.16%乳酸菌培养物L1、L2、L3。试验期42 d,分1~21日龄(前期)和22~42日龄(后期)2个阶段。结果显示,1~21日龄时,乳酸菌培养物L1组肉鸡平均日采食量极显著高于对照组和抗生素组(P<0.01),血清中白介素-2(IL-2)含量显著低于对照组(P<0.05),脾脏指数、胸腺指数、法氏囊指数均显著高于对照组(P<0.05);乳酸菌培养物L2组肉鸡脾脏指数、胸腺指数显著高于对照组(P<0.05);乳酸菌培养物L3组肉鸡平均日增重极显著高于对照组和抗生素组(P<0.01);抗生素组肉鸡血清中γ-干扰素(IFN-γ)含量显著高于乳酸菌培养物组(P<0.05)。22~42日龄时,乳酸菌培养物L1、L2组肉鸡平均日增重极显著高于对照组和抗生素组(P<0.01);乳酸菌培养物L2组肉鸡血清中免疫球蛋白G(IgG)含量显著高于抗生素组(P<0.05),血清新城疫抗体效价及脾脏指数、胸腺指数、法氏囊指数均显著高于对照组(P<0.05);乳酸菌培养物L3组肉鸡血清中免疫球蛋白A(IgA)含量及胸腺指数显著高于对照组(P<0.05)。由此可知,在肉鸡日粮中添加一定量的灭活乳酸菌培养物可在一定程度上提高肉鸡的生长性能、增强其免疫功能,其中,对于提高肉鸡的生长性能,试验前期添加L3效果较好,试验后期添加L1和L2效果较好;对于增强肉鸡的免疫功能,试验前期添加L1效果较好,试验后期添加L2效果较好。     

复合酵母培养物对奶牛产奶性能、氮排放及血液生化指标的影响

为研究饲料中添加复合酵母培养物对奶牛产奶性能、氮排放及血液生化指标的影响,选取年龄、体重、产奶量及泌乳期相近(135±15) d的荷斯坦奶牛24头,随机分为4组,每个处理6个重复,对照组和3个试验组的复合酵母培养物添加量分别为精料浓度的0,0.8%,1.0%,1.2%,随精料饲喂,测定产奶量、乳成分、氮排放及血液生化指标,结果表明,1)试验2组日均产奶量显著高于对照组(P<0.05),各试验组分别比对照组提高8.48%,10.05%,8.97%。2)复合酵母培养物能显著提高乳脂和乳蛋白率(P<0.05),显著降低牛奶体细胞数(P<0.05),以试验2组最低。3)在氮排放量上,试验2组显著低于对照组(P<0.05),各试验组比对照组分别降低8.47%,12.01%,9.36%。4)在血液生化指标方面,复合酵母培养物能提高血清中总蛋白、球蛋白、血糖、胰岛素水平(P<0.05),降低尿素氮水平(P<0.05)。由此可见,本试验条件下,综合考虑产奶量、乳成分、氮排放及血液生化指标,复合酵母培养物的最佳添加量为精料浓度的1.0%。     

无籽西瓜组培脱毒与离体嫁接技术研究

利用无籽西瓜种胚进行组培脱毒与西葫芦离体嫁接研究。结果表明:不同消毒剂对种胚萌发有一定影响,其中消毒剂二氧化氯250 mg/L处理有利于种胚萌芽,萌发率达86.7%。6-BA对茎尖分化有促进作用,浓度0.2 mg/L对芽分化有显著作用;不同激素浓度对芽丛增殖和单芽生根也有一定影响,其中MS+6-BA 0.5 mg/L+IAA 1 mg/L继代培养增殖率最高;MS+NAA 0.2 mg/L生根率最高(83.9%)。采用无菌嫁接成活率(77.5%)高于开放式嫁接成活率(37.5%);经ELISA检测,对WMV-2(西瓜花叶病毒2号)、ZYMV(小西葫芦黄化花叶病毒)的脱毒率分别为75%和80%。     

几种微生物及其组合在猪粪堆肥发酵中的作用

猪场粪便是重要污染源,但又是一类尚未充分利用的资源.研究了酵母、枯草芽孢杆菌、木霉与黑曲霉4种微生物对猪粪堆肥发酵的促进作用,并探讨几种微生物在堆肥发酵时的相互作用,同时开发出一种能令猪粪堆肥快速升温腐熟的发酵剂.结果表明,发酵剂的配比为芽孢杆菌:黑曲霉:木霉=3:2:3,酵母在升温过程中所起作用不明显.中试结果表明,用此配比的发酵剂,可以令猪粪堆肥在10d左右腐熟,并且使得堆肥产品的种子发芽指数提高21.7%.     

“宋明理学”对封建社会发展的影响评析

“宋明理学”将中国古代哲学发展到了一个高峰。理学家以儒家礼法、伦理思想为核心,糅合道教万物化生理论和佛教思辨哲学,建立了一个比较精致、圆滑的哲学体系。它对中国封建社会的政治、文化、社会、教育等发展产生了深刻影响。但在看到它积极意义的同时,更要认识到其根本的历史局限性,应有选择地加以扬弃。