四种与福寿螺(Ampullaria gigas)同源地入侵植物的杀螺效果

实验室内观察了福寿螺在其主要危害对象水稻,及与其同源地的入侵植物五爪金龙、马缨丹、胜红蓟和蟛蜞菊５种植物新鲜叶片间聚集数量差异,结果显示:15min后福寿螺在距离其约75cm 的5种植物叶片聚集数产生了显著的差异,但75min内福寿螺在5种植物叶片间聚集的数量不稳定,75min后的聚集数趋于稳定,5种植物叶片上聚集福寿螺数由多到少顺序为蟛蜞菊、马缨丹、水稻、胜红蓟和五爪金龙。福寿螺取食水稻幼苗的量较大,显著高于取食另4种植物新鲜叶片的量,福寿螺取食4种与其同源地植物叶片量由小到大的顺序为：五爪金龙、蟛蜞菊、胜红蓟和马缨丹。不同浓度4植物乙醇提取物水溶液对福寿螺毒杀作用差异显著,乙醇提取物饱和水溶液致福寿螺100%死亡的时间由短到长的顺序为：五爪金龙48h, 蟛蜞菊72h, 胜红蓟和马缨丹均为96h,按常规施用量化学农药密达100%毒杀福寿螺的时间为118h。综合结果表明五爪金龙具有开发出既能有效防治福寿螺又不影响水稻生长和稻田环境材料的潜力。     

五爪金龙乙醇提取物对福寿螺毒杀和水稻苗生长的影响

福寿螺和五爪金龙是两种危害严重的入侵生物,利用五爪金龙防治稻田福寿螺是以害治害的方法.盆栽条件下研究了五爪金龙乙醇提取物毒杀福寿螺的效果,以及其对水稻苗生长的影响.在砂培条件下五爪金龙乙醇提取物及其分离得到的甲醇相、乙酸乙酯相、乙醚相水溶液不仅对福寿螺起到毒杀作用, 而且对水稻秧苗生长有促进作用, 毒杀和促进作用由强到弱的顺序均为:乙醇提取物>甲醇相>乙酸乙酯相>乙醚相.在实验浓度范围内五爪金龙乙醇提物对福寿螺的毒杀效果及其对水稻苗促进作用强度均随浓度的增大而增强,在水稻土盆栽条件下抑制福寿螺取食水稻苗的效果与密达差异不显著(p>0.05).五爪金龙乙醇提取物能毒杀福寿螺,对水稻苗的生长没有不利的影响.因此, 利用五爪金龙防治稻田福寿螺危害是环境友好的非化学防治措施,具有良好的应用前景.     

蓖麻籽提取液对福寿螺毒杀效果及作用机制

采用生物浸泡法, 以草本植物蓖麻籽提取液制备植物源毒杀剂, 研究不同提取液浓度(0、0.5、1.5、3.0、4.5、6.0 g/L)对福寿螺(Pomacea canaliculata Lam)毒杀作用效果, 并通过福寿螺在亚致死浓度1.58(LC₂₅)、3.82(LC₅₀)和6.05 g/L(LC₇₅) 处理条件下的肝脏组织生理生化指标及其相关性, 进一步分析其毒杀作用机制。结果表明: 在提取液处理48h后, 福寿螺死亡率随着时间延长和浓度的增加而增加, 且各浓度处理下福寿螺死亡率差异显著(P<0.05)。福寿螺在亚致死浓度处理48h后, 其肝胰腺组织中蛋白质含量(TP)、丙二醛(MDA)含量和过氧化氢酶(CAT)活性与对照组均存在差异, 过氧化氢酶(CAT)活性与丙二醛(MDA)含量呈显著负相关关系(P<0.05)。蓖麻籽提取液通过影响福寿螺肝脏组织中蛋白质含量(TP)和丙二醛(MDA)含量, 及过氧化氢酶(CAT)活性, 导致螺肝脏组织损伤, 机体代谢紊乱, 从而达到毒杀效果。     

四种入侵植物提取液对褐云玛瑙蜗牛的防控效果

实验室内观察了4种入侵植物水提取液对褐云玛瑙蜗牛成体和幼体的触杀及抑制蜗牛卵发育效果的差异性。结果表明:(1)以1.0 g/mL薇甘菊和南美蟛蜞菊水提取液对蜗牛喷杀处理, 对蜗牛触杀的有效时间分别为82 h和118 h;马樱丹触杀蜗牛的致死时间和有效时间最慢,4种入侵植物水提取液对成体褐云玛瑙蜗牛触杀效果强弱顺序为:薇甘菊 > 南美蟛蜞菊 > 五爪金龙 > 马缨丹。(2)1.0 g/mL 的4种入侵植物水取液对幼体蜗牛触杀的有效时间比成体蜗牛缩短2倍以上,幼体蜗牛个体死亡数量呈急剧增加趋势, 而成体蜗牛个体死亡数量呈相对平缓的增加趋势。(3)1.0、1.5 g/mL及2.0 g/mL薇甘菊水提取液对成体蜗牛触杀效果差异显著(P < 0.05)。以2.0 g/mL薇甘菊水提取液触杀蜗牛的有效时间最短, 与10%的四聚乙醛处理组相当, 为78 h, 显著少于1.5 g/mL的96 h和1.0 g /mL 的130 h。(4)褐云玛瑙蜗牛卵发育对1.0 g/mL 的4种入侵植物水提取液的干扰表现更为敏感。1.0 g/mL的薇甘菊水提取液抑制蜗牛卵发育的效果最好, 抑制率达81.67%,且与其它处理组间存在显著差异(P < 0.05)。而1.0 g/mL的马缨丹提取液优于五爪金龙提取液对褐云玛瑙蜗牛卵的抑制效果则表明入侵植物内源次生成分对不同发育时期的动物的防控效果存在差异。1.0 g/mL入侵植物水提取液各处理组对褐云玛瑙蜗牛卵发育抑制效果由强至弱的顺序为:薇甘菊 > 南美蟛蜞菊 > 马缨丹 > 五爪金龙。总之, 4种入侵植物对褐云玛瑙蜗牛成体、幼体和卵均具有较好的触杀与抑制作用, 利用入侵植物防控入侵动物, 以害制害, 化害为利, 是一种具有良好应用前景的环境友好型生物防治措施。     

五爪金龙中香豆素类物质含量及其对福寿螺、水稻和稗草的影响

在不同季节采集并测定了入侵植物五爪金龙不同器官中伞形花内酯(Umbelliferone(UMB))和东莨菪亭内酯(Scopoletin(SCO))的含量、同时室内分析了这两种物质的杀螺效果及其对水稻和稗草生长的影响、并研究了这两种物质在土壤中的降解情况。结果表明:五爪金龙植株中SCO含量高于UMB含量,两物质均是夏季含量最高,春季次之,秋冬季低,SCO夏季在茎中含量最大,秋冬季幼茎和幼叶中含量较高;UMB对福寿螺的毒杀力强于SCO,UMB浓度为C2(200μg/mL)时处理24 h对福寿螺的致死率达100%,而SCO浓度为C2时处理24 h对福寿螺的致死率仅为8%;SCO对水稻和稗草苗生长的影响较UMB强,在C0(50μg/mL),C1(100μg/mL)、C2浓度下均促进水稻及稗草苗的生长,而C3(400μg/mL)浓度下则抑制水稻和稗草苗的生长。UMB和SCO混合溶液比单一物质在相同浓度的杀螺效果及对水稻和稗草的生长影响要强;UMB和SCO在土壤中10 d内完全降解。入侵植物五爪金龙中的次生物质UMB和SCO在稻田中的生态效应值得进一步研究。     

惠州红树林自然保护区外来入侵植物调查

采用线路调查与样方调查相结合的方法,对惠州红树林自然保护区内好招楼和蟹洲湾两区域内的外来入侵植物进行了调查。两区域均有49种植物,共有外来入侵植物21种,好招楼和蟹洲湾分别有外来入侵植物12和16种,占植物总种数的24.49%和32.65%。其中,在好招楼分布较广的种类有毛花雀稗(Paspalum dilatatum Poir.)、无瓣海桑(Sonneratia apetala Buch.-Ham.)、三裂蟛蜞菊〔Wedelia trilobata(L.)Hitchc.〕和胜红蓟(Ageratum conyzoides L.)等,在蟹洲湾分布广泛的种类有假臭草(Eupatorium catarium Veldkamp)、马缨丹(Lantana camara L.)及胜红蓟等。大多数外来入侵植物原产美洲,其中14.29%作为有用物种有意引入,61.90%随货物和运输工具无意引入,23.81%随风和水流自然传入。外来入侵植物对红树林的直接危害较轻,但对保护区的景观生态和生物多样性有严重威胁。     

假臭草等12种植物对白花鬼针草幼苗的化感作用

用具有化感作用或潜在抑草活性的12种植物的叶片水浸液对白花鬼针草(Bidens alba)幼苗进行处理,对其幼苗的生长 进行研究,以期筛选出对白花鬼针草生长有较强抑制作用的植物种类。结果表明,12种供体植物叶片水浸液(0.05 g DW mL^-1) 均能显著抑制白花鬼针草幼苗的生长(P<0.05),综合化感效应(SE)均为负值(≤-0.2),抑制强度依次为假臭草(Eupatorium catarium)>胜红蓟(Ageratum conyzoides)>海芋(Alocasia macrorrhiza)>水茄(Solanum torvum)>马缨丹(Lantana camara)>薇甘菊(Mikania micrantha)>构树(Broussonetia papyrifera)>南美蟛蜞菊(Wedelia trilobata)>三裂叶薯(Ipomoea triloba)>葛藤(Pueraria lobata)>鸡矢藤(Paederia scandens)>五爪金龙(Ipomoea cairica),其中假臭草叶水浸液浓度仅为0.04 g DW mL^-1时就可以使白花鬼针草死亡。假臭草和胜红蓟的茎水浸液也可以显著抑制白花鬼针草的生长(P<0.05),抑制效果略低于叶水浸液。回归分析表明,假臭草叶水浸液浓度与白花鬼针草的生物量等指标之间有线性回归关系(R²>0.85, P<0.001),随着水浸液浓度的增加,白花鬼针草的生物量等指标下降。防除白花鬼针草时使用假臭草和胜红蓟的茎、叶水浸液, 其有效浓度低且资源丰富,可作为白花鬼针草天然除草剂的主要资源植物。     

3种入侵植物叶片挥发物对旱稻幼苗根的影响

入侵植物通过化感作用对入侵地的生态系统构成了严重的威胁,影响了入侵域农作物的生产。采用石蜡切片技术,利用光学显微镜进行观察,研究了不同质量浓度的黄顶菊、三叶鬼针草、胜红蓟3种入侵植物的叶片挥发物对旱稻幼苗初生根的结构以及根系发育的影响,结果表明:低质量浓度(5g)的三叶鬼针草和胜红蓟叶片挥发物对根皮层起抑制作用,低质量浓度(5g)的三叶鬼针草挥发物对维管柱有促进作用,而黄顶菊挥发物对髓腔影响比较大,表现为低浓度抑制,高浓度促进;20g质量浓度的三种入侵植物叶片挥发物对旱稻幼苗初生根结构影响最大,均出现结构上的变异;对侧根的发育随浓度的增加而呈现明显的抑制作用,20g质量浓度时没有侧根的发生。表明入侵植物对受体植物根结构的影响随植物种类和挥发物浓度的不同而有不同的特点。     

入侵植物五爪金龙生物学特性研究

通过栽培实验,观察入侵植物五爪金龙的形态学特征,测定两个不同生长期的生物量、根茎长度等指标,对实验数据进行统计分析,从几个方面研究五爪金龙的生物学特性。结果表明:生长期为6个月的五爪金龙生物量与生长期为3个月的五爪金龙生物量相比,根、茎、叶分别增长了2~5倍;平均含水量在7.41%~82.99%之间,两者无显著差异;两者之间的根冠比存在显著差异,但是跟其他草本植物相比,其根冠比相对较小;不同生长期的平均根长度分别为57cm、87cm,平均茎长度分别为319cm、714cm,两者之间的根茎比存在极显著差异。研究结果为进一步研究五爪金龙的入侵机制和控制五爪金龙的对策提供科学的理论依据。     

外来入侵植物的氮代谢及其土壤氮特征

研究了4种外来入侵植物(五爪金龙、南美蟛蜞菊、金腰箭和马缨丹)和1种本地植物鸡矢藤(对照)的氮代谢及其土壤氮特征.结果表明:外来人侵植物的组织硝酸还原酶活性、根际土壤NH4-N、NO3-N含量、蛋白酶活性和脲酶活性均较高,分别为鸡矢藤的1.65～4.34、1.56～2.15、1.72～3.11、1.43～3.23和1.41～3.33倍,而植物组织硝态氮含量则较低,仅为鸡矢藤的17.5%～50.6%.相关分析表明:植物组织硝酸还原酶活性与根际土壤总氮、NH4-N、NO3-N含量呈显著正相关(P<0.05),与蛋白酶活性和脲酶活性呈极显著正相关(P<0.01).这说明,外来植物入侵使土壤氮代谢加快,氮的生物有效性增强,氮同化能力提高,并且较好地将植物体氮素代谢与土壤氮素代谢协调起来.因此,较强的氮素同化能力与加速土壤氮素的转化可能是植物成功入侵的重要机制之一.     

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.