内生贪铜菌的分离鉴定及其对铜污染含羞草生长的影响

【目的】研究贪铜菌及其与含羞草(Mimosa pudica)形成的共生体对重金属铜污染的抗性,为重金属污染环境的微生物修复提供参考,丰富功能菌株资源库。【方法】自含羞草根瘤中分离得到菌株HXC-8,扩增该菌株的16S rDNA序列,对其进行鉴定,并对其进行生理生化特性测定,研究菌株HXC-8对重金属铜的耐受性及去除率。此外,设置接菌组（含羞草种子在HXC-8菌悬液中浸泡6 h、自然阴干1 h）和未接菌组（含羞草种子在蒸馏水中浸泡6 h、自然阴干1 h）,将2组含羞草种子在Cu²⁺质量浓度分别为0,50,100,150,200,250,300,350,400 mg/L的混合营养液中培养,分析菌株HXC-8对铜胁迫下含羞草种子萌发和幼苗生长的影响。【结果】16S rDNA基因序列分析结果显示,菌株HXC-8为贪铜菌属（Cupriavidus sp.）细菌,将其命名为“贪铜菌HXC-8”。生理生化特性测定结果显示,贪铜菌HXC-8为革兰氏阴性菌,能分泌活性较高的H₂O₂酶和淀粉酶,不产生纤维素酶,不适合在肉汁培养基上生长,在糖代谢过程中无混合酸发酵,属于快生型内生菌。随着Cu²⁺质量浓度的升高,贪铜菌HXC-8的生长受到了抑制,该菌对Cu^2＋的耐受量是0～150 mg/L。当Cu^2＋质量浓度为25~150 mg/L时,随着菌液中Cu^2＋质量浓度的增大,贪铜菌HXC-8对铜的去除率逐渐降低,其中Cu^2＋质量浓度为25 mg/L时,贪铜菌HXC-8对铜的去除率最高,为97.93%。在0~400 mg/L Cu²⁺胁迫下,随Cu²⁺质量浓度的升高,未接菌组和接菌组含羞草种子萌发率均无显著变化,但种子活力指数明显下降;未接菌组和接菌组含羞草幼苗鲜质量、根长、茎长及株高均明显降低。当Cu²⁺质量浓度为0～300 mg/L时,接菌组与未接菌组含羞草幼苗鲜质量、根长、茎长、株高均无显著差异;当Cu²⁺质量浓度为350~400 mg/L时,接菌组幼苗以上指标均明显大于未接菌组。【结论】贪铜菌HXC-8对铜具有一定的耐受性,能够降低环境中游离态的Cu²⁺,可减缓重金属铜对含羞草生长的胁迫。     

重金属镉对含羞草种子萌发和幼苗生长的影响

以不同浓度的镉(Cd)离子溶液处理含羞草种子,研究了镉对其种子萌发和幼苗生长的影响.结果表明:处理液中的镉浓度小于20 mg/L时,对含羞草种子萌发的影响较小;当镉浓度大于40 mg/L时,对含羞草种子萌发有明显的抑制作用,且抑制程度随着镉浓度的提高而加强;此外,随着处理液镉浓度的提高,对含羞草种子萌发后幼芽、幼根及幼苗生长的抑制作用明显加强,且镉对幼根生长的影响大于对芽的影响.     

含羞草石蜡切片的制作

通过对含羞草进行取材、固定、脱水、透明、浸蜡、切片、脱蜡、染色、透明等一系列过程的试验研究,掌握了含羞草石蜡切片的制作方法,总结出了含羞草石蜡切片制作过程中的关键技术,并通过显微观察分析,从解剖学上为研究含羞草的运动机理提供了理论基础。     

鬼针草与含羞草化感作用及其入侵性的研究

采用培养皿滤纸法研究入侵植物鬼针草与含羞草根、茎、叶浸提液对种子萌发和幼苗生长的影响,从化感角度揭示外来植物的入侵机制。结果表明:1)鬼针草根、茎、叶浸提液随浓度升高显著抑制鬼针草和含羞草种子萌发,高浓度(0.04 g·mL^-1)的叶浸提液使萌发率降低了67%~87%;高浓度(0.04 g·mL^-1)的含羞草叶浸提液使其种子萌发率降低了21.7%,但对鬼针草种子萌发影响较小。2)鬼针草和含羞草根长随2种植物根、茎、叶浸提液浓度的升高而降低,尤其是高浓度的叶浸提液有较强抑制效应。3)各浓度的鬼针草根、茎、叶浸提液均能降低含羞草茎长,高浓度的叶浸提液抑制效应最强;高浓度(0.04 g·mL^-1)的含羞草茎和叶浸提液抑制鬼针草茎长,中等浓度(0.02~0.03 g·mL^-1)的根和叶浸提液促进鬼针草茎长;含羞草各器官浸提液对其茎长的抑制作用随浓度增大略有增强。4)鬼针草各器官浸提液(尤其叶浸提液)抑制自身根冠比,促进含羞草根冠比;含羞草各器官浸提液轻微降低自身根冠比,显著降低鬼针草根冠比。5)鬼针草对自身种子萌发率、根长及根冠比的化感强度大于鬼针草他感强度;鬼针草对含羞草茎长的化感强度大于其自感强度,也大于含羞草他感强度;含羞草对鬼针草根长及根冠比的化感强度大于其自感强度,也大于鬼针草他感强度。鬼针草主要通过抑制含羞草茎长,增强入侵性,而含羞草主要通过抑制鬼针草根的生长,增大竞争力。     

不同营养液水培对含羞草生长发育的影响

采用水培方法,以清水培养为对照,研究了不同营养液配方对含羞草(Mimosa pudica)生长发育的影响。结果表明,含有0.9446 g·L^-1Ca(NO₃)₂.4H₂O、0.8088g·L^-1KNO₃、0.1495g·L^-1NH₄H₂PO₄和0.4929 g·L^-1 MgSO₄·7H₂O的营养液(配方B)所处理植株的各项形态指标均明显优于其它配方,叶绿素含量和过氧化氢酶活性也高于其它配方。而丙二醛(MDA)的含量与其它配方相比差异不显著。     

Traditional fallow systems of the Americas

Six neotropical traditional fallow systems are described: 1) enriched fallows of the Amazon, 2) Babassu palm (Orbignya phalerata Mart.) forests of central and northern Brazil, 3) bracatinga (Mimosa scabrella Benth) improved fallow of southeastern Brazil, 4) carbon negro (Mimosa tenuiflora Willd.) fallow of the wet-dry zone of Mesoamerica, 5) frijolillo (Senna guatemalensis Donn. Smith) of high-elevation zones in southern Honduras, and 6) caragra (Lippia torresii) fallow of humid zones of Costa Rica.These systems include both biologically and economically enriched fallows. Some (e.g., the enriched fallows of the Amazon) require a considerable degree of human intervention, while others (e.g., the bracatinga and carbon negro fallows) seem to form with little human encouragement, following the burn in shifting cultivation systems. Some of the systems (e.g., frijolillo and caragra) are quite site-specific and have a limited distribution; others (e.g., babassu, bracatinga, and carbon negro) occur over large areas and could be adapted to considerable areas in the Americas. As economic analyses are generally lacking, it is unclear what benefits would be achieved from a wider use of these systems. Most of the biologically enriched fallows seem able to maintain low yields of food crops at low input levels. Some of the economically enriched fallows seem able to produce higher economic returns.     

含羞草药学研究进展

概述了含羞草的种属、成分、药理和临床应用等方面的研究进展,为进一步开发利用提供理论依据。     

Influence of impregnating wood particles with mimosa bark extract on some properties of particleboard

In this study, influence of impregnating wood particles with mimosa bark extract on the some properties of particleboard was investigated. Properties evaluated were modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), thickness swelling (TS), and formaldehyde emission (FE). The results showed that particleboards made from particles impregnated with mimosa bark extract had significantly lower mechanical, physical and formaldehyde emission values than those of the boards made from unimpregnated particles. Brushing of mimosa bark extract to the surfaces and edges of the particleboards did not affect the mechanical properties, statistically. However, this application caused a significant improvement in the thickness swelling and formaldehyde emission.     

Growth Parameters and Nutrient Content in Four Multipurpose Tree Species with Potential Characteristics for Agroforestry Systems in a Cerrado Region in Botucatu,São Paulo State,Brazil

Abstract

In order to evaluate growth characteristics, adaptability, biomass production, nutrient recycling, nutrient distribution and the ability to regenerate degraded land, a trial using four multipurpose tree species (Leucaena leucocephala, Leucaena diversifolia, Acacia melanoxylon and Mimosa scabrella) was undertaken over two years in a distrophic red yellow latosol (oxisol) following a randomized block experimental design with four replications.

At the age of two years, A. melanoxylon and L. diversifolia were the tallest species (5.25 and 4.97 m, respectively) and A. melanoxylon and M. scabrella had the largest diameters at 20 cm from tree base.

Mimosa scabrella and A. melanoxylon had the highest dry matter production and quantity of nutrients in the above ground biomass. In all species, the highest nutrient contents were found in the leaves, followed by branches and stems. From all species, the highest Nutrient Utilization Efficiency Indexes were obtained for sulphur, phosphorous, and magnesium; L. diversifolia was the most efficient for nitrogen, potassium, calcium, sulphur, and manganese, while A. melanoxylon was the most efficient for phosphorus, magnesium, boron, iron, and zinc. Litter production levels over a three month period were as follows: M. scabrella > A. melanoxylon > L. diversifolia > L. leucocephala. Litter nutrient content was higher in M. scabrella than in the other species.     

不同生长调节剂处理对三种绿肥种子发芽率的影响

研究赤霉素（GA3）、6-苄氨基嘌呤（6BA）、萘乙酸（NAA）、吲哚丁酸（IBA）四种植物生长调节剂．设不同溶液浓度、不同浸种时间处理对爪哇葛藤、无刺含羞草及羽叶决明种子发芽率的影响,结果表明：生长调节剂对促进种子发芽率有一定作用;不同生长调节剂对不同”绿肥种子萌发的影响不尽相同,以GA3促萌发效果最好,以无刺含羞草受影响效果最显著;低生长调节剂浓度水平（15或25mg／L）和浸种24h或48h是较佳的处理组合,而高浓度的生长调节剂对促进发芽率无影响或有抑制作用。