拟南芥直播水培法

在参考国内外水培拟南芥的经验和方法的基础上,采用简易的水培装置,对拟南芥直播水培方法进行了探索.     

一种适于营养胁迫研究的拟南芥水培方法

水培法可通过更换营养液来控制根际营养成分,成为植物营养学研究的最佳培养方式。由于根际通气和微生物滋生等问题,拟南芥(Arabidopsis thaliana)的水培技术始终无法被广泛应用。该文利用Eppendorf离心管管盖和离心管盒,将拟南芥种子在琼脂上萌发和植株水培有机结合,通过控制营养液用量和液体深度,增加营养液表面积,解决了水培过程中根系通气问题。利用离心管管盖作为支撑材料,降低了琼脂水分蒸发,并减少琼脂的用量和厚度,从而实现琼脂和营养液的快速平衡,为拟南芥培养和营养胁迫研究提供了一个简单且经济的水培方法。     

丙氨酸胁迫对拟南芥和烟草离体培养的影响

目的:筛选拟南芥和烟草种子离体培养的最佳培养基,并在最佳培养基下研究丙氨酸胁迫对其生长的影响.方法:在MS和1/2MS基本培养基中添加不同激素,筛选拟南芥和烟草种子的最适培养基配方,在最适培养基上加入不同浓度的D-和L-丙氨酸.结果与讨论:1/2NS不附加任何激素的基本培养基植株生长最好;D-丙氨酸对拟南芥生长有强烈抑制作用,L-丙氨酸则对生长无显著影响;D-型和L-型丙氨酸均对烟草有强烈抑制作用,这与经典的反馈抑制机理不很一致.     

植物种子特异基因调控网络研究

通过比较种子植物与蕨类植物的基因及其调控网络,为研究种子性状出现的分子机制提供更多的信息.下载拟南芥(Arabidopsis thaliana)种子特异基因和基因网络数据,构建拟南芥种子特异基因调控网络,并与江南卷柏(Selaginella moellendorffii)基因组数据比较,发现其中重要的调控节点.分析得到构成调控网络的1053个拟南芥种子特异基因,其中的969个基因形成一个复杂的调控网络.该网络的核心模块包括39个基因,形成哑铃状的子网络,其中重要节点基因AT1G54860只存在于种子植物基因组中.AT1G54860基因编码GPI锚定蛋白,参与细胞壁的形成、细胞间信号传导及生长分化等过程,推测其在种子形成中具有重要地位,可能起了"开关"的作用.     

一种拟南芥无菌直播水培技术

一般拟南芥的水培方法多是开放的体系(郁晓敏等2004;赵淑清和郭剑波2000),培养时间长时容易滋生菌类和青苔,影响植株正常生长。Ezaki等(2000)采用尼龙筛网和海绵缝在一起作为     

冬凌草甲素对拟南芥种子萌发和幼苗生长的化感作用

以拟南芥为供试材料,研究了二萜化合物冬凌草甲素(oridonin)对拟南芥种子萌发、幼苗生长及生理特性的化感作用。结果表明:(1)各浓度冬凌草甲素处理均降低了拟南芥种子的发芽率、发芽势、发芽指数和种子活力指数;至最终萌发时间,120μmol/L冬凌草甲素处理的种子发芽率、发芽势和发芽指数、种子活力指数分别为对照的87.76%、70.37%、83.19%、27.72%,说明高浓度的冬凌草甲素对拟南芥种子发芽率、发芽势、发芽指数和种子活力指数均有显著抑制作用,且对种子活力指数的影响最为显著。(2)冬凌草甲素处理后培养拟南芥幼苗2周,60μmol/L冬凌草甲素处理的拟南芥根甚至出现侧根不生长的现象;120μmol/L冬凌草甲素处理的幼苗主根长度比对照组降低了79.05%,其鲜重、干重和相对含水量分别降为对照的58.41%、63.33%和93.91%。(3)不同浓度和时间的冬凌草甲素处理整体上显著促进了拟南芥幼苗体内渗透调节物质可溶性蛋白和脯氨酸的积累。研究发现,冬凌草甲素对拟南芥种子萌发及生长表现出不同程度的化感抑制作用,该抑制作用与冬凌草甲素的处理浓度及处理时间均密切相关;拟南芥幼苗能通过增加自身渗透调节物质积累在一定程度上缓解这种抑制作用。     

UV-B辐射对拟南芥种子萌发和幼苗生长的影响

以哥伦比亚生态型(Columbia-0)拟南芥(Arabidopsis thaliana)为实验材料, 人工模拟UV-B辐照处理拟南芥种子, 统计其发芽势和发芽率, 测定根长、株高、叶绿素、可溶性糖、可溶性蛋白以及丙二醛(MDA)含量, 研究UV-B辐照处理对拟南芥种子萌发和幼苗生长的影响。研究结果表明, 低剂量的UV-B辐照可以促进拟南芥种子萌发和幼苗生长, 并且最佳辐照剂量为1.0 kJ·m^–2(P<0.05), 此时的发芽势、发芽率、根长、株高、叶绿素、可溶性糖及可溶性蛋白的含量均达到最大, 而丙二醛的含量变化则不明显(P>0.05)。当辐照剂量大于1.0 kJ·m^–2时, 促进作用逐渐变小, 并且随着辐照剂量的增加, 表现出了抑制作用。实验结果表明, 适当剂量的UV-B辐照在一定程度上可以促进拟南芥种子萌发和幼苗生长, 而过高剂量的辐照则对其产生抑制或损伤作用。     

He-Ne激光处理对拟南芥种子萌发和幼苗生长特性的影响

以哥伦比亚生态型(Columbia-0)的野生型拟南芥为材料,利用He-Ne激光生物辐照仪(632.8nm,5mW/mm2)处理拟南芥种子,统计其发芽势和发芽率,并测定根长及叶绿素、可溶性糖、可溶性蛋白和丙二醛(MDA)的含量,以探讨He-Ne激光对拟南芥种子萌发和幼苗生长的影响。结果显示,短时间的He-Ne激光辐照可促进拟南芥的生长发育,且最佳辐照时间为4min,此时的发芽势、发芽率、根长、叶绿素、可溶性糖及可溶性蛋白的含量均达到最大,而丙二醛(MDA)的含量为最低。当辐照时间大于4min时,促进作用逐渐变小,且随着辐照时间的延长而表现出抑制作用。研究表明,适量的He-Ne激光辐照在一定程度上可以促进拟南芥种子的萌发和幼苗生长以及保护其细胞膜免受伤害。     

Leukamenin E调节拟南芥幼苗生长发育的模式及其机制

研究对映-贝壳杉烷型二萜化合物Leukamenin E对拟南芥种子萌发、下胚轴伸长以及根生长发育的作用模式,并探讨植物激素生长素和乙烯可能介导Leukamenin E影响拟南芥主根生长、侧根和根毛发育的初步机制。结果表明:Leukamenin E浓度在10~160μmol·L~(-1)范围对拟南芥种子的萌发率无显著影响,但高浓度Leukamenin E(80~160μmol·L-1)显著抑制种子的萌发速率。Leukamenin E对拟南芥幼苗根生长的抑制作用明显高于对下胚轴的抑制效应。进一步研究表明,Leukamenin E通过阻滞根尖细胞有丝分裂和细胞伸长进而抑制主根的生长,并能促进侧根提前发生并影响其形成数量,同时减少根毛密度及降低根毛长度。Leukamenin E联合乙烯利(乙烯释放剂)处理可阻止乙烯利单独使用对拟南芥幼苗根毛生长的促进作用,与Ag+(乙烯竞争抑制剂)联合乙烯利的作用效果相一致,表明Leukamenin E可能通过干扰根细胞乙烯途径而抑制根毛发育。流动注射化学发光分析和酶联免疫检测的结果发现,Leukamenin E显著上调拟南芥幼苗根组织中生长素(IAA)水平,表明生长素可能作为主要因子介导了Leukamenin E对拟南芥幼苗根生长发育的调节作用。     

黄梁木NcEXPA8基因提高拟南芥种子萌发速度的研究

为探究NcEXPA8基因的分子功能,该文以在黄梁木形成层区域中高表达的扩展蛋白基因NcEXPA8为研究对象,研究其在黄梁木种子萌发过程中的表达及其过表达对拟南芥种子萌发的影响。该文以黄梁木和拟南芥野生型(WT)(Col-0)种子以及转NcEXPA8基因的拟南芥T3代纯合体种子为实验材料,利用实时荧光定量RT-qPCR分析NcEXPA8基因在黄梁木种子萌发不同阶段的表达量,并分析NcEXPA8基因和拟南芥种子萌发内源相关基因在拟南芥WT和转基因不同株系萌发种子中的表达量,且对拟南芥WT种子和转基因T3代纯合体种子在不同处理和不同时间的萌发率进行比较。结果表明:NcEXPA8基因在黄梁木种子萌发不同阶段的表达量存在差异,在种壳破裂时表达量最高,随后降低。与拟南芥WT相比,过表达NcEXPA8基因不仅显著提高了种子的萌发速度,而且提高了对赤霉素的敏感性,降低了对脱落酸的敏感性,但未影响拟南芥内源相关结构基因的表达。该研究初步分析了黄梁木NcEXPA8基因在种子萌发中的功能,但其最终确定还需在黄梁木中进行验证。     

A convenient and versatile hydroponic cultivation system for Arabidopsis thaliana

A versatile two-step cultivation procedure for Arabidopsis thaliana is described for the production of large quantities of leaf material suitable for biochemical and biophysical analysis. The first step comprises a miniature greenhouse made out of a plastic pipette box to grow the seedlings to the six-leaf stage. For continued growth, the seedlings are transferred to hydroponic cultivation using an opaque container covered by a styrofoam lid. Transfer of the small seedlings to hydroponic culture is facilitated by growth in separate pipette tips, which protects vulnerable roots from damage. The hydroponic cultivation system is easy to scale-up and produces large amounts of relatively large leaves and roots. This hydroponic system produces enough plant material to make Arabidopsis a feasible model for biochemical and biophysical experiments, which can be combined with the available genetic information to address various aspects of plant functional genomics.     

An improved,simple, hydroponic method for growing<Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Arabidopsis thaliana is one os the most studied plant model systems. Completing the genomic sequence ofA. thaliana has provided new opportunities for physiological and biochemical studies. While its small size is advantageous for genetic studies, the plant's low biomass makes it difficult to obtain enough plant material for biochemical and physiological research. The small size and rosette leaf structure, combined with the sensitivity of the apical meristem to flooding, make hydroponic growth of this model plant difficult. A few systems for hydroponic culture ofArabidopsis have been described. Gibeaut et al. (1997) introduced the use of rockwool forArabidopsis hydroponic culture. We have improved this system by introducing small-volume plastic containers with improved plugs to support the rockwool. This method is simpler than the original setup and provides improved germination and growth. The smaller containers enable the use of this system in growth chambers or small growth rooms for a large number of parallel experiments.     

A simple hydroponic culture method for the development of a highly viable root system in Arabidopsis thaliana

In the studies of nutritional absorption and metal toxicity in the root, it is important to grow plants without technical damage. We established a simple hydroponic culture system for Arabidopsis thaliana to obtain a healthy plant having a well-developed root system with many lateral roots. The phytotoxic effects of Cr, Cu, and Al ions were examined by FDA-PI staining using this culture system. The pattern of root inhibition varied with the ion, suggesting the usefulness of this culture system.     

A Simple Hydroponic Culture Method for the Development of a Highly Viable Root System in Arabidopsis thaliana

In the studies of nutritional absorption and metal toxicity in the root, it is important to grow plants without technical damage. We established a simple hydroponic culture system for Arabidopsis thaliana to obtain a healthy plant having a well-developed root system with many lateral roots. The phytotoxic effects of Cr, Cu, and Al ions were examined by FDA-PI staining using this culture system. The pattern of root inhibition varied with the ion, suggesting the usefulness of this culture system.     

A novel method for growing Arabidopsis thaliana plants hydroponically

In this report we describe the development of a simple system for growing individual Arabidopsis plants hydroponically under environmental conditions which are simple to maintain while maximizing growth and development. The system consists of a Life Raft Float Unit with a 14–20 mm sponge inserted into its center; this unit is placed into a Magenta GA7 vessel containing Arabidopsis nutrient solution. Plants grown in this experimental system do not require aeration, 125 μmol m⁻² s⁻¹ supports vigorous plant growth, 1/4 to 1/8 strength Arabidopsis nutrient solution promotes maximal growth while higher or lower levels have adverse effects and temperatures between 18 and 24°C were found to be optimal. Plants grown under these conditions exhibit physiological factors such as time to flowering and overall appearance similar to those grown in potting media. The low maintenance method described in this paper provides an alternative to existing hydroponic methods used to grow Arabidopsis . Adaptation of this system for growing large numbers of plants in 1 container is also discussed.     

A novel high efficiency,low maintenance,hydroponic system for synchronous growth and flowering of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>

Background  

Arabidopsis thaliana is now the model organism for genetic and molecular plant studies, but growing conditions may still impair the significance and reproducibility of the experimental strategies developed. Besides the use of phytotronic cabinets, controlling plant nutrition may be critical and could be achieved in hydroponics. The availability of such a system would also greatly facilitate studies dealing with root development. However, because of its small size and rosette growth habit, Arabidopsis is hardly grown in standard hydroponic devices and the systems described in the last years are still difficult to transpose at a large scale. Our aim was to design and optimize an up-scalable device that would be adaptable to any experimental conditions.     

Critical evaluation and statistical validation of a hydroponic culture system for Arabidopsis thaliana.

Arabidopsis thaliana is one of the most widely used model organisms in plant sciences. Because of the increasing knowledge in the understanding of its molecular pathways, a reproducible and stable growth set-up for obtaining uniform plants becomes more important. In order to be able to easily harvest and study both roots and shoots, and to allow simple exposure to water-soluble toxic substances, a hydroponic system is the desired cultivation method for controlled plant growth. Based on earlier developed hydroponic cultivation protocols, a hydroponic set-up was optimized and statistically validated using linear mixed-effects models. In order to determine important components that influence the level of variability in a hydroponic set-up, stress-related indicators were examined at the biochemical as well as at the molecular level. It is highly recommended that statistical as well as biological assumptions are carried out before post-analyses are performed. Therefore, we suggest a model where factors that influence variability such as the usage of different pots and harvesting on different times are taken into account in the analyses. Furthermore, in contrast to what has been reported in earlier studies, our findings indicate that continuous aeration of the hydroponic solution is highly important.     

Tree planting in organic soils does not result in net carbon sequestration on decadal timescales

Tree planting is increasingly being proposed as a strategy to combat climate change through carbon (C) sequestration in tree biomass. However, total ecosystem C storage that includes soil organic C (SOC) must be considered to determine whether planting trees for climate change mitigation results in increased C storage. We show that planting two native tree species (Betula pubescens and Pinus sylvestris), of widespread Eurasian distribution, onto heather (Calluna vulgaris) moorland with podzolic and peaty podzolic soils in Scotland, did not lead to an increase in net ecosystem C stock 12 or 39 years after planting. Plots with trees had greater soil respiration and lower SOC in organic soil horizons than heather control plots. The decline in SOC cancelled out the increment in C stocks in tree biomass on decadal timescales. At all four experimental sites sampled, there was no net gain in ecosystem C stocks 12–39 years after afforestation—indeed we found a net ecosystem C loss in one of four sites with deciduous B. pubescens stands; no net gain in ecosystem C at three sites planted with B. pubescens; and no net gain at additional stands of P. sylvestris. We hypothesize that altered mycorrhizal communities and autotrophic C inputs have led to positive ‘priming’ of soil organic matter, resulting in SOC loss, constraining the benefits of tree planting for ecosystem C sequestration. The results are of direct relevance to current policies, which promote tree planting on the assumption that this will increase net ecosystem C storage and contribute to climate change mitigation. Ecosystem‐level biogeochemistry and C fluxes must be better quantified and understood before we can be assured that large‐scale tree planting in regions with considerable pre‐existing SOC stocks will have the intended policy and climate change mitigation outcomes.