冷季型草坪草的耐热性调控研究进展

在非生物胁迫中,高温是影响草坪植物特别是对冷季型草坪草生长和发育最重要的生态因子之一. 高温胁迫会导致冷季型草坪草生长受到抑制、草坪质量下降、草坪植株体内的生理生化代谢紊乱,细胞内产生大量氧自由基,使膜脂过氧化,植株体内蛋白质变性,最后导致细胞死亡. 因此,如何提高冷季型草坪草的耐热性是目前冷季型草坪在热带、亚热带地区建植能否安全越夏的重要问题. 文中综述了国内外冷季型草坪草耐热性调控的研究进展, 在阐明冷季型草坪草耐热性调控原理的基础上,报道了用于草坪草耐热性鉴定的形态、生态、生理和生化等指标,以及通过降低土壤温度、叶面喷施生长调节剂、施肥、灌溉和修剪等养护管理措施来提高冷季型草坪草的耐热性研究进展.     

酯酶基因扩增及突变与昆虫抗药性

有机磷和氨基甲酸酯类杀虫剂的大量使用导致昆虫对其产生抗药性。酯酶是昆虫体内重要的解毒代谢酶,酯酶基因表达量上升和点突变使其代谢或结合杀虫剂的能力增强是昆虫对常用农药产生抗药性的2个重要原因。文章概述昆虫酯酶基因扩增及突变所导致的抗药性,进一步分析了酯酶突变对蛋白结构和功能的影响。     

气候变化下极端高温对昆虫种群影响的研究进展

全球平均温度升高导致极端高温事件发生幅度、频率和持续时间增加,对生物和生态系统造成显著影响.以往气候变暖与昆虫种群关系的研究多关注平均温度的变化,常导致过高地估计了温度升高对昆虫的正面作用,而忽视了自然界存在的极端高温的不利影响.本文综述了气候变化下极端高温对昆虫种群地理分布、种群统计参数和种群增长、行为及种间关系等影响的研究进展.极端温度通过限定昆虫的适宜温度阈限和耐受温度范围决定其在不同纬度、海拔和景观地区的分布.极端高温通过即时和后续效应抑制昆虫的发育、存活、繁殖等核心生命参数,进而改变了昆虫种群统计参数和种群增长.极端高温可通过影响昆虫的体温调节、取食及扩散等行为改变其发育、繁殖等核心生命参数.昆虫对极端高温的反应具有物种特异性,不同种类昆虫对气候变化的响应不同,导致相对优势度、群落结构、食物链等种间关系发生变化,进而影响生态系统的功能.目前关于极端高温对昆虫种群影响的研究多关注发生在夏季的热浪天气和日间极端高温.气候变化导致温度的升高在季节间具有非对称性,发生在春、秋、冬季节相对的极端高温对昆虫种群未来发展的影响将是未来该领域研究的重点.     

极端高温和持续中等高温对小菜蛾耐热性的影响

气候变化频率的增加和持续时间的延长,导致具有较短生活史的大部分农业害虫的某一个或某几个生命阶段都可经历热浪的胁迫。热浪对小型昆虫的生态学效应取决于不同生命阶段的耐热性,因而解析特定龄期下昆虫生命阶段的耐热性对理解气候变暖热浪频发的生态学影响具有重要意义。本研究以世界重要蔬菜害虫小菜蛾为研究对象,试验了小菜蛾4龄幼虫、成虫的基底耐热性和诱导耐热性,以及1龄幼虫和3龄幼虫置于不同高温[(31±1)、33±1)、35±1)℃]和暴露时间(3、6、9、12d)组合的持续中等高温耐热性。试验发现幼虫和成虫具有不同的基底和诱导耐热性,具有较弱基底耐热性的幼虫反而具有更强的诱导耐热性。不同生命阶段在持续数天的中等高温胁迫下具有不同的存活表现,早期生命阶段存活率较后期阶段的低,而且这种差异在较强高温下表现得尤为明显。昆虫不同阶段耐热性的差异,对种群的维持具有重要的生态学意义。大多数农业害虫田间种群具有混合年龄结构,热浪后耐热的发育阶段的存活,保证种群可以一直生存和繁衍下去。     

害早抗药性的生化机理

害虫的抗药性是与杀虫剂穿透昆虫表皮速率降低,解毒作用增强和靶标部位敏感性降低有关。昆虫体内多功能氧化酶、磷酸酯酶、羧酸酯酶、谷胱甘肽－Ｓ－转移酶和脱氯化氢酶活力的增加是害虫抗性的主要生化机理。抗性昆虫体内乙酰胆碱酯酶对杀虫剂敏感性降低,中枢神经组织敏感性降低和“抗击倒基因”的存在是拟除虫菊酯类杀虫剂的主要抗性机制。     

短时高温胁迫对中华地鳖蛋白质和氨基酸含量的影响

土鳖虫体内富含蛋白质和氨基酸,是一种重要的药用昆虫。高温对昆虫生命活动产生重要影响。为探明短时高温胁迫对土鳖虫体内蛋白质和氨基酸含量的影响,本试验以中华地鳖Eupolyphaga sinensis Walker 8龄雌若虫为研究对象,通过人工设置29℃、33℃、37℃为高温处理组,以25℃为对照,测定2 h短时高温胁迫对中华地鳖存活率以及体内蛋白质和氨基酸含量的影响。结果表明:29℃、33℃和37℃短时高温处理对中华地鳖存活率无影响,蛋白质含量分别为76.57%±3.29%、79.60%±0.92%、77.00%±0.71%,与对照(84.50%±1.57%)相比均明显下降;短时高温处理后,29℃处理组土鳖虫总氨基酸含量为206.97±7.42 mg/g,6种人体必需的游离氨基酸苏氨酸8.23±0.32 mg/g,甲硫氨酸3.98±0.49 mg/g,异亮氨酸8.27±0.35 mg/g,亮氨酸16.38±0.86 mg/g,苯丙氨酸8.34±0.40 mg/g,以及赖氨酸12.56±0.64 mg/g的含量较对照和33℃、37℃高温处理组均显著升高,表明29℃短时高温处理可显著提高中华地鳖体内人体必需游离氨基酸含量。本研究是国内外对高温胁迫下药用昆虫体内活性成分的首次报道,研究结果将为进一步明确高温对土鳖虫的药用价值的影响,以及为土鳖虫人工养殖条件提供理论依据。     

害虫抗药性的生化机理

害虫的抗药性是与杀虫剂穿透昆虫表皮速率降低,解毒作用增强和靶标部位敏感性降低有关。昆虫体内多功能氧化酶、磷酸酯酶、羧酸酯酶、谷胱甘肽－Ｓ－转酶和脱氯化氢酶活力的增加是害虫抗性的主要生化机理。抗性昆虫体内乙酰胆碱酯酶对杀虫剂敏感性降低,中枢神经组织敏感性降低和“抗击倒基因”（Ｋｄｒ）的存在是拟除虫菊酯类杀虫剂的主要抗性机制。     

昆虫体内章鱼胺的分布、功能及其研究进展

章鱼胺是无脊椎动物神经系统中普遍存在的多种微量生物胺之一。章鱼胺的分布及含量变化对于昆虫的生长、取食、代谢等多种生理、生物效应具有重要的作用。文章对昆虫体内章鱼胺的功能性、昆虫体内章鱼胺的分布及其主要功能、章鱼胺痕量测定方法、生存环境的改变及化学药剂的作用对章鱼胺含量的影响以及外界刺激对章鱼胺含量影响的生理及生物化学机理研究进行了综述。     

极端嗜热微生物及其高温适应机制的研究进展

极端嗜热微生物在高温条件下生长繁殖,其必然具有适应高温环境的特殊细胞结构、基因类型以及生理生化机制。极端嗜热微生物的研究对探索生命的起源以及极端嗜热微生物的开发和应用具有重要意义。对极端嗜热微生物中细胞膜、核酸分子、蛋白质分子、代谢产物和辅酶的高温适应机制的研究进展进行了概述,旨为极端嗜热微生物以及来源于极端嗜热微生物的各种生物分子的开发和应用提供理论依据。     

硫氧还蛋白与氧化还原反应

硫氧还蛋白是生物体调节体内氧化还原系统的一种重要蛋白质,它参与了生物体内众多的氧化还原反应,其活性位点是-Cys-Gly-Pro-Cys-,在众多的生命过程中,通过构象的改变行使其调节功能。     

六种藓类植物茎的比较解剖学研究

通过对6种藓类植物,即褶叶青藓(Brachythecium salebrosum(Web.et Mohr.)B.S.G.)、湿地匐灯藓(Plagiomnium acutum(Lindb.)Kop.)、侧枝匐灯藓(Plagiomnium maximoviczii(Lindb.)Kop.)、大凤尾藓(Fissidensnobilis Griff.)、大羽藓(Thuidium cymbifolium(Doz.et Molk.)B.S.G.)和大灰藓(Hypnum plumaeforme Wils.)嫩茎和老茎的石蜡切片和显微观察发现,同一藓类植株的嫩茎和老茎,茎结构稳定,不同种藓类植物茎横切面具有不同特征.植物体茎横切面形状、表层细胞的层数、细胞大小和细胞壁厚薄、皮层细胞大小和形状、中轴的有无以及比例等特征可以作为藓类植物的分科分类依据之一.     

Cause of Senescence of Nine Sorts of Flowers

The levels of endogenous phytohormones and respiratory rate in nine sorts of flowers such as Cymbidium faberi Rolfe, Nopalxochia ackermannii Kunth and others were investigated both at full bloom and senescence and meanwhile the effect of exogenous phytohormones on prolonging the blossoms and promoting ethylene production were tested. There is a high content of endogenous ethylene in all the long-lived flowere, about 3–16 folds higer than the short-lived ones. There is a high level of ABA at full blooming flowers of short-lived flowers, in which there is no or only some cytokinins in it, but the ratio of CTK (6BA+zeatin)/ABA is smaller(l.7). The endogenous ABA reached a much higher level at senescence in all nine sorts of flowers, so it is reasonable to consider that it is ABA which plays an important role of regulation in controlling flower's senescence. There is a much higher level of GA3 and zeatin in the long-lived flowers which is not demonstrated in the shortlived ones. The respiratory rate is one of the factors controtling the longevity of flowers, but it does not play a decided role. Application of 6BA and zeatin prolongs distinctly orchid’s longevity, however exogenous IAA through the promotive action on ethylene production, evidently extends the longevity of the flowers of the Nopalxochia ackermannii Kunth.     

龙胆科药用植物化学成分的研究现状

龙胆科植物在我国的分布范围很广,且多数为药用植物,其多数种属的药用植物,至今其化学成分尚未被系统研究。综述了目前龙胆科药用植物的化学成分的研究现状及一般提取方法,对近年来发现的环烯醚萜及裂环烯醚萜类化合物进行了总结,为本科药用植物的更深入研究提供了参考。     

The effects of glutamine of the maintenance of embryogenic cultures of Cryptomeria japonica

Summary Embryogenic tissues of sugi (Cryptomeria japonica) were induced on a modified Campbell and Durzan (CD) medium containing 1 μM 2,4-dichlorophenoxyacetic acid (2,4-D) and 600 mg l⁻¹ glutamine, and subcultured in the medium of the same composition for over 1 yr. This resulted in a mixed culture of embryogenic and non-embryogenic cells. When embryogenic cells were isolated and cultured independently, their capacity to form embryogenic aggregates was lost. Thus, the non-embryogenic cells present within a mixed culture system were essential to the formation of embryogenic aggregates. When embryogenic tissues were isolated and cultured independently on a high glutamine-containing (2400 mg l⁻¹) medium, dry weights and endogenous levels of glutamine increased, and the tissue could generate a large number of embryogenic aggregates. Amino acid analysis of embryogenic and non-embryogenic cells from the maintenance culture indicated a higher level of glutamine was present in the latter. The high endogenous level of glutamine in the non-embryogenic portion of mixed cell masses may be the supplier of glutamine for maintaining the embryogenic property of the tissues.     

Specificity of action of piperidylcholine derivatives as substrates of cholinesterases of various origin

The review deals with study of enzymologic properties of a novel highly specific acetylcholinesterase substrate, N-(β-acetoxyethyl) piperidinium iodomethylate (“piperidylcholine”), and its 30 derivatives that were tested as effectors of cholinesterases of mammals and various species of Pacific squids. It was proven for the first time that responsible for specificity of action was structure of cyclic ammonium grouping of the alcohol part of molecule of the ester substrate. Analysis of specificity is performed based on enzymatic hydrolysis parameters—activity of catalytic center of cholinesterases and bimolecular constant of the reaction rate that are determined at optimal and low substrate concentrations. Among the specially synthesized group of thioester compounds there is revealed one more highly specific acetylcholinesterase substrate—N-(β-acetoxyethyl) piperidinium.     

真菌类遗传学分析的知识结构教学

本文以认知结构理论为指导,讨论了真菌类遗传分析与高等动植物遗传分析的内在联系,认为利用这种内在联系进行教学可收到好的效果并说明了作者的具体教学过程。 Abstract:In the paper, the relationship between genetic analysis of Fungi and genetic analysis of high animal and plant was discussed.A good results were obtained when we adopted this method in the teaching.     

医疗机构合理用药评价模型的构建研究

目的 针对医疗机构的合理用药水平进行评价研究。方法 根据医疗机构合理用药的具体要求,构建医疗机构合理用药评价指标体系,采用基于模糊群决策的方法和多指标评价分析法构建医疗机构合理用药评价模型。结果 构建了基于模糊群决策的医疗机构合理用药评价模型,并通过实例分析证明了评价模型的可行性。结论 建立的基于模糊群决策的医疗机构合理用药评价模型能够对医疗机构的合理用药水平进行科学评价,为提高医疗机构合理用药水平奠定基础。     

Photoregulation of seed germination of wild-type and of an aurea-mutant of tomato

Seed germination of an aurea mutant of tomato ( Lycopersicon esculentum Mill.) is promoted by continuous irradiation with red, far-red or long-wavelength far-red (758 nm) light as well as by cyclic irradiations (5 min red or 5 min far-red/25 min darkness). Far-red light applied immediately after each red does not change the germination behaviour. Seed germination of the isogenic wild-type, cv. UC-105, is promoted by continuous and cyclic red light while it is inhibited by continuous and cyclic far-red light and by continious 758 nm irradiation. Far-red irradiation reverses almost completely the promoting effect of red light. The promoting effect (in the aurea mutant) and the inhibitory effect (in the wild-type) of continuous far-red light do not show photon fluence rate dependency above 20 nmol m⁻² s⁻¹. It is concluded that phytochrome controls tomato seed germination throgh low energy responses in both the wild type and the au mutant. The promoting effect of continuous and cyclic far-red light in the au mutant can be attributed to a greater sensitivity to P_fr.