果粮间作模式优化调控研究Ⅳ:系统养分管理及其优化对策探讨

我国农林复合经营(Ａｇｒｏｆｏｒｅｓｔｒｙ)历史悠久,有许多实践已证明的成功模式类型,果农间作就是分布面积最大的代表类型[1～3,8]。目前,已有的研究主要集中于类型划分[1,2,8]生态和经济效益定量观测和评价[1～10]、模式的建立[3,4,8]、资源的经营利用特点[1,2,5～10]等方面,基本上都是针对现状而进行,尚缺乏对进一步提高果农间作模式效益的优化调控研究。果粮间作条件下最大的矛盾是果与粮相互竞争可利用资源(光、热、水和土壤养分等)而导致粮食的减产和土壤的过渡利用[1,6,7]。如何优化调控,以进一步提高生态和经济效益,达到提高土地…     

贵州省安顺市土地资源信息空间数据库的建立与应用

1　引　　言要制订不会危及环境的土地资源开发和保护计划 ,必须首先掌握可靠的、较新的有关土地资源的时空信息[3 ] .近年来 ,以ＧＩＳ和遥感技术为主的现代信息科学技术在土地覆盖/利用调查与填图[2 ,6] 、土地资源动态变化监测[13 ] 、土地质量退化与土壤侵蚀监测[5,8] 、土地资源评价[12 ] 与管理[10 ] 中得到了广泛应用 .这些技术可以较好地解决以往传统方法在获取、分析和处理大量、复杂土地信息中的众多限制 ,使我们得以动态地、综合地分析土地资源环境信息[4,7] .贵州省安顺市地处我国西南岩溶山区 ,生态环境脆弱 ,土地资源相对不足…     

云南地方稻核心种质耐低磷特性研究

1引言磷是作物的必需性营养元素,人类将面临农业可持续发展与磷素资源严重短缺的矛盾[17].土壤普查结果表明,全国有59%以上的土壤缺磷[1].为了提高作物产量,生产中通过施用磷肥来解决土壤缺磷的问题.由于磷肥利用率低,不仅增加生产成本,还带来资源短缺、环境污染及食品安全等诸多问题[21,26].发掘水稻利用磷的内在潜力,培育磷高效利用新品种,可减少磷的施用量.近年来,野生或地方稻绿色基因发掘及改良进展显著,如资源高效利用[22~24]、高产基因[3,20,27]和抗性基因[2,13]等,利用植物基因型间磷元素利用效率的差异,筛选和培育磷高效基因型作物…     

麝凤蝶形态观察及生物学特性

麝凤蝶Ｂｙａｓａａｌｃｉｎｏｕｓ(Ｋｌｕｇ)属鳞翅目凤蝶科 ,分布于我国大部分地区和日本、朝鲜等国 ,寄主植物是马兜铃、木防己。在浙江省 ,该蝶自然条件下 1年可繁殖 3代 ,以蛹越冬。该蝶成虫双翼狭窄、尾突修长 ,飞翔姿态优雅 ,极具观赏性 ,是蝴蝶馆内放飞展出的适宜种类。至目前为止 ,已有国内外学者在麝凤蝶成虫的发生[1] 、形态[3 ,6,7] 、生殖系统[8～ 10 ] 、性信息素[11] 、亚种的杂交[12 ] 和幼虫的饲料[13 ] 及蛹体的滞育[14 ] 等方面有过报道或有一些研究 ,但很少对其人工饲养和繁殖进行研究。为了保护生态环境 ,开发蝴蝶资源…     

遮光和施氮对暗紫贝母形态特征和生物量分配的影响

根据最优分配理论( optimal partitioning theory,OPT),在自然环境中,由于地上和地下资源在空间上的分离,陆生植物需要调整其地上和地下部分的生物量分配以平衡对资源的吸收。研究结果[1-2]显示：在植物地上资源严重受限时,叶片的生物量分配相对增加;而地下资源严重受限时,根的生物量分配相对增加。然而,植物的生物量分配对资源的响应较为复杂。首先,除了生物量分配,形态变化也是植物调节资源吸收的重要手段,例如,植物通过增加比叶面积提高对光照的吸收,通过调整比根长响应土壤养分的变化[3-4];并且,一些植物甚至以形态响应为主,生物量分配的变化并不明显[3,5]。此外,某些植物还有一些特殊的资源平衡方式,例如,克隆植物通过构件之间的养分传输平衡资源在空间上的分配不均[6];拥有特化储藏器官的植物可依靠大量储藏物质来平衡资源在时间上的分配不均[7]。植物所具有的丰富的资源响应方式决定了其多样的资源策略。     

光皮桦优良单株自由授粉子代苗期性状的遗传变异

光皮桦 (ＢｅｔｕｌａｌｕｍｉｎｉｆｅｒａＨ .Ｗｉｎｋｌ.)为落叶阔叶大乔木 ,零星分布于我国南方各省 (区 ) [1] 。近年来 ,由于装饰装璜市场对光皮桦木材的需求量急剧增加 ,使得天然林遭到过度采伐 ,造成光皮桦天然林资源锐减 ,致使光皮桦可利用资源极少 ,处于渐危状态。有关学者就光皮桦的天然种群结构、种群动态等进行研究 ,探明了光皮桦种群的结构特征和种群演变规律等[2～ 5] ,对光皮桦的繁殖方法及苗期生长特性也进行了探讨 ,揭示苗期生长特性随时间序列的变化趋势[6,7] ;但在遗传改良方面的研究甚少[8] 。鉴于此 ,作者在现有天然…     

浙江五岭坑常绿阔叶林优势种群的生态位特征

采用定量分析法计测了浙江五岭坑常绿阔叶林12 种优势种群的生态位指数。结果表明: (1)小叶青冈、厚皮香、木荷的生态位宽度较大,而赤楠、短尾柯、米槠的生态位宽度较小。物种的重要值与其生态位宽度之间没有明显的相关性。(2)生境需求相似而生态位宽度较小的具毛常绿荚蒾与赤楠的生态位相似性比例最大, 具毛常绿荚蒾与米槠的生态位相似性比例最小。甜槠与米槠之间的生态位相似性比例较小。优势种群的生态位相似性比例总体水平较向, 平均值为0.6446。(3)群落优势种群的生态位重叠平均值为0.1219。甜槠与米槠之间的生态位重叠较小。群落优势种群之间的生态位重叠程度不大, 说明该群落因利用相同资源而产生的种间竞争不大。     

两种野生花卉的扦插繁殖研究

开展野生花卉车轮梅(Raphiolepis indica)和赤楠(Syzygium buxifolium)扦插试验,结果表明:车轮梅硬枝扦插需一定浓度的外源激素方能生根;对激素浓度大小不敏感;总体上NAA组合生根质量优于IBA组合。综合不同处理生根率、根数和不定根根长3个指标,以800 mg/L NAA或800 mg/L IBA作为车轮梅生产上扦插的激素种类和浓度。赤楠生根率较低,最高扦插率达66.7%,生根时间长,约需45 d始生根。综合生根率、不定根根数和不定根根长3个生根指标,试验的4种激素均能较好促进赤楠生根,200×根太阳在生根率和根数上效果最好,生产上可用200×根太阳浸泡2 h,也可用50-100 mg/L NAA或100-400 mg/L IBA浸泡2 h后进行扦插。     

大雾岭保护区野猪种群数量、结构及繁殖习性的初步研究

野猪 ( Susscrofa)是重要的资源兽类之一 ,几乎广布于我国各地 ,国外见于欧洲、非洲和亚洲。至今已记录的亚种有 2 3个 ,我国 6个 [1～ 3] ,由于大量捕杀和栖息地破坏 ,其数量下降很快 ,不少地方已很难见到 [1,4 ] 。广东已将野猪列为省重点保护动物。开展野猪生态学的研究 ,可为野猪资源的保护和利用提供科学依据。近年来 ,国外对野猪的种群生态学的研究十分活跃 ,内容广而深入 [5～ 12 ] ,而国内迄今只有几篇综述性的报道 [13～ 16 ] ,仅有高中信等对小兴安岭地区野猪冬季卧息地选择进行了较为细致的研究 [4 ] 。笔者于 1 996年 5月至 1 …     

鸡[土从]菌属与华鸡[土从]属分类研究现状

鸡[土从]菌是一类世界著名珍贵食用菌。依据收集的标本和国内外大量的文献资料,归纳总结了世界鸡[土从]菌资源的概况,比较2个属及40个种的形态、分类特征及分布范围,提出了世界鸡[土从]菌的分类检索表。     

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.     

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.     

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.     

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.     

Interconnection of parameters of regulation system of lipid peroxidation and of morphophysiological parameters of mouse liver

A complex analysis of seasonal fluctuations of the mean group parameters of the system of regulation of lipid peroxidation has been performed in liver of Balb/c mice. Association of lipid characteristics and morphophysiological parameters is studied in the Balb/c mouse liver. An inter-connection is revealed between the liver index and the amount of lysoforms of phospholipids, the scale and character of the interconnection differing essentially depending on proportion of phos-phatidylcholine in mouse liver phospholipids.     

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。     

Physiological characteristics of various species of strains of carboxydobacteria

Seven strains of aerobic carbon monoxide-oxidizing bacteria (carboxydebacteria) when growing on CO as sole source of carbon and energy had doubling times which ranged from 12–42 h. The activity profiles obtained after discontinuous sucrose density gradient centrifugation indicated that the CO-oxidizing enzymes are soluble and the hydrogenases are membrane-bound in all strains examined. The CO-oxidizing enzymes of Pseudomonas carboxydohydrogena, Pseudomonas carboxydoflava, Comamonas compransoris, and the so far unidentified strains OM2, OM3, and OM4 had a molecular weight of 230,000; that of Achromobacter carboxydus amounted to 170,000. The molecular weights of the CO-oxidizing and H₂-oxidizing enzymes turned out to be identical. The cell sonicates were shown to catalyze the oxidation of both CO and H₂ with methylene blue, thionine, phenazine methosulfate, toluylene blue, dichlorophenolindophenol, cytochrome c or ferricyanide as electron acceptors. Methyl viologen, benzyl viologen, FAD⁺, FMN⁺, and NAD(P)⁺ were not reduced. The spectrum of electron acceptors was identical for all strains tested. Neither free formate, hydrogen nor oxygen gas were involved in the CO-oxidation reaction. Methylene blue was reduced by CO at a 1:1 molar ratio. The results indicate that CO-oxidation by carboxydobacteria is catalyzed by identical or similar enzymes and that the reaction obeys the equation CO+H₂OCO₂+2H⁺+2e^- as previously shown for Pseudomonas carboxydovorans.Dedicated to Otto Kandler remembering almost three decades of enjoyable cooperation     

Modulation of allostery of pyruvate kinase by shifting of an ensemble of microstates

Since the introduction of the concepts of allostery about four decades ago, much advancement has been made in elucidating the structure-function correlation in allostery. However, there are still a number of issues that remain unresolved. In this review we used mammalian pyruvate kinase (PK) as a model system to understand the role of protein dynamics in modulating cooperativity. PK has a triosephosphate isomerase (TIM)(α/β)₈ barrel structural motif. PK is an ideal system to address basic questions regarding regulatory mechanisms about this common (α/β)₈ structural motif. The simplest model accounting for all of the solution thermodynamic and kinetic data on ligand-enzyme interactions involves two conformational states, inactive E^T and active E^R. These conformational states are represented by domain movements. Further studies provide the first evidence for a differential effect of ligand binding on the dynamics of the structural elements, not major secondary structural changes. These data are consistent with our model that allosteric regulation of PK is the consequence of perturbation of the distribution of an ensemble of states in which the inactive E^T and active E^R represent the two extreme end states. Sequence differences and ligands can modulate the distribution of states leading to alterations of functions. The future work includes: defining the network of functionally connected residues; elucidating the chemical principles governing the sequence differences which affect functions; and probing the nature of mutations on the stability of the secondary structural elements, which in turn modulate allostery.