湿地植物生长模型在红树林湿地人工恢复调控中的应用--以珠江口淇澳岛红树林湿地恢复为例

选取珠江口淇澳岛红树林人上恢复为例,借助湿地大型植物生长控制模型,通过3种不同预案的设置,定量分析外来种无瓣海桑与生态侵入种互花米草之间的竞争关系。研究表明：在有互花米草的滩涂上人工种植的无瓣海桑．在其生物量小于互花米草生物量时,初始生物量大的超过互花米草所需时问短于初始生物量小的;当无瓣海桑生物量超过互花米草生物量后．无瓣海桑生长基本小受互花米草的影响,同时互花米草的生物量开始下降。在人工付出劳动相同的情况下（即人人工割除互花米草的频度）．初始生物量大的无瓣海桑超过互花米草生物量所需的时间短于初始生物最小的无瓣海桑。     

红树林湿地烷烃降解菌的分离筛选

从受石油污染的红树林湿地土样中分离筛选对烷烃具较高降解能力的细菌菌株, 以期应用于被石油污染滨海湿地的生物修复。采用富集培养方法, 富集、分离和筛选烷烃降解菌;观察各菌落及菌体形态特征;测试菌株Z2的生理生化特征, 并用16S rDNA序列分析方法进行该菌种鉴定。分离筛选得到Z1、Z2和Z3这3个能以正十六烷为唯一碳源生长的菌株, 其降解率依次为63.4%、82.5%和78.3%, 其中菌株Z2的降解率最高。经过形态学观察、生理生化特性实验和16S rDNA序列分析鉴定, 菌株Z2为不动杆菌(Acinetobacter sp.)。     

四株红树林促生菌的遗传分析鉴定及其促生能力

【目的】鉴定四株供试菌株的种属地位,了解菌株所具有的促进植物生长能力。【方法】运用nifH与16S rRNA基因序列对供试菌株进行遗传分析,采用钼锑抗比色法和乙炔还原法分别测定菌株的溶磷、固氮能力。通过接种试验验证菌株促进红树植物生长的能力。【结果】通过对菌株nifH与16S rRNA的同源性、系统发育树分析,HN011与需钠弧菌(Vibrio natriegens)的相似性最高,SZ7-1、SZ7-2与产酸克雷伯氏菌(Klebsiella oxytoca)的相似性最高。而SZ002在16S rRNA的系统发育分析中归属为类芽孢杆菌属(Paenibacillus sp.),却在nifH基因分析中与克雷伯氏菌(Klebsiella sp.)的相似性最高。供试菌株都具有较强的溶磷能力和高固氮酶活性。接种后植株有较好的生长表现,部分接种植株在干重、全氮、全磷含量等方面较对照有显著地增加(P0.05)。【结论】首次发现兼具溶磷-固氮两种能力的红树林植物促生菌,接种试验也表现菌株具有良好的促生能力,为红树林人工接种促生菌的应用提供了可靠的理论依据。     

红树林湿地模型研究进展

红树林是位于海岸潮间带的森林湿地生态系统,具有抗风削浪、保护堤岸、封存CO₂缓解全球气候变化等多种功能。然而,由于地理位置及生存环境特殊,红树林湿地模型的研究相对内陆湿地滞后。为了推动红树林湿地模型的研究,本文将目前常见红树林湿地模型按功能划分为植被生长生产模型、水文模型、物流能流模型三类,以阐述相关模型研究的进展,并对目前红树林湿地模型研究提出几点看法:(1)现有红树林湿地模型在不同区域、尺度下运行的有效性有待进一步验证;(2)国内对红树林生态系统服务及植被恢复工作相关模型研究较少,今后需加强该方面的研究。     

植物与菌根菌

菌根是土壤中的真菌与高等植物根系所形成的共生体。共生真菌从植物体内获得碳水化合物等营养物质,而植物根也从真菌那里得到所需的营养元素和水,从而互利共生,共同进化。有趣的是,有些真菌对于一种植物来说是菌根菌,而对另一种植物来说可能是寄生菌或病原菌。据统计,种子植物中９５％以上的种能与接合菌、子囊菌、担子菌等亚门的真菌共生,形成菌根。菌根学者习惯上根据其形态解剖学特征,将菌根分为三大类：外生菌根、内生菌根、内外生菌根。外生菌根是菌根真菌菌丝体包围植物尚未木栓化的营养根形成的,其菌丝体不侵染到皮层细胞内…     

植物内生菌及其开发应用研究进展

内生菌是一类新的微生物资源,能够产生多种生物活性物质,具有重大的研究价值,开发前景广阔。本文介绍了植物内生菌的概念和分布,并阐述了植物内生菌在国内外医药、农业领域的开发应用研究现状,旨在为进一步研究植物内生菌提供新的思路。     

红树林植物露兜树营养成分分析

本文对红树林植物露兜树的营养成分进行了分析,结果表明,露兜树中含有多种营养成分,丰富的矿质元素和维生素及其β-胡萝卜素。露兜树中至少含有17种氨基酸。旨在为开发利用植物资源提供科学依据。     

红树林湿地在海岸生态系统维护中的功能*

综述了红树林湿地在海岸生态系统中所具有的维护生物多样性、防风消浪、促淤护岸、防灾减灾、净化海水、调节大气和美化海岸带景观等方面的功能。探讨了广东及华南沿海红树林的分布状况和存在问题,指出了华南沿海现存的红树林湿地正在遭受严重的威胁和破坏。华南沿海现存红树林湿地面积仅有1.5×10⁵hm²,比历史最大面积减少了70%;广东省的红树林湿地由10年前的1.47×10⁴hm²减少到现在的9100hm²,减少了38%。提出了建立和完善红树林自然保护网络系统、积极实施红树林湿地生态修复工程、注重红树林的引种和种苗培育技术研究、充分评估红树林湿地的巨大生态效价等对策与建议。     

福建红树林植物丛枝菌根侵染研究

2010年5月和12月,对福建沿海3个红树林生长区(洛阳江、九龙江口、漳江口)的红树林植物丛枝菌根（AM）侵染状况进行研究。结果表明：（1）红树林生长区中6种植物根内均发现AMF侵染结构,其中桐花树、秋茄、鱼藤和芦苇的丛枝为Arum（疆南星）型;（2）6种植物的丛枝菌根侵染率差异较大,老鼠簕的侵染率最高,鱼藤最低;（3）桐花树和秋茄的丛枝菌根侵染率呈显著差异,而其在不同生长区之间无差异;（4）桐花树和秋茄的丛枝菌根侵染率在不同时间呈显著差异,而钝草的丛枝菌根侵染率在不同时间的差异不显著。     

油菜素内酯（BR）促进植物生长机理研究进展

介绍了油菜素内酯促进植物生长,提高作物产量的作用,并简述了促进生长的生理代谢基础,通过比较油菜素内酯与生长素,赤霉素促进生长作用方式的异同,提出油菜素内酯促进生长的信号传导路径不同于其它植物激素,另外从细胞的形态发生,细胞壁扩展的机制和细胞骨架在细胞伸长中的作用等几个方面对油菜素内酯促进植物生长的细胞及分子生物学机制进行了详尽的论述。     

Plant growth-promoting bacteria as inoculants in agricultural soils

Plant-microbe interactions in the rhizosphere are the determinants of plant health, productivity and soil fertility. Plant growth-promoting bacteria (PGPB) are bacteria that can enhance plant growth and protect plants from disease and abiotic stresses through a wide variety of mechanisms; those that establish close associations with plants, such as the endophytes, could be more successful in plant growth promotion. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promotion (PGP) traits. Bacterial inoculants can contribute to increase agronomic efficiency by reducing production costs and environmental pollution, once the use of chemical fertilizers can be reduced or eliminated if the inoculants are efficient. For bacterial inoculants to obtain success in improving plant growth and productivity, several processes involved can influence the efficiency of inoculation, as for example the exudation by plant roots, the bacterial colonization in the roots, and soil health. This review presents an overview of the importance of soil-plant-microbe interactions to the development of efficient inoculants, once PGPB are extensively studied microorganisms, representing a very diverse group of easily accessible beneficial bacteria.     

Plant growth-promoting bacteria that decrease heavy metal toxicity in plants

Kluyvera ascorbata SUD165 and a siderophore-overproducing mutant of this bacterium, K. ascorbata SUD165/26, were used to inoculate tomato, canola, and Indian mustard seeds which were then grown in soil for 25-42 days in the presence of either nickel, lead, or zinc. The parameters that were monitored included plant wet and dry weight, protein and chlorophyll content in the plant leaves, and concentration of heavy metal in the plant roots and shoots. As indicated by a decrease in the measured values of these parameters, in all instances, plant growth was inhibited by the presence of the added metal. Both bacterial strains were effective, although not always to a statistically significant extent, at relieving a portion of the growth inhibition caused by the metals. In most cases, the siderophore overproducing mutant K. ascorbata 165/26 exerted a more pronounced effect on plant growth than did the wild-type bacterium K. ascorbata SUD165. The data suggest that the ability of these bacteria to protect plants against the inhibitory effects of high concentrations of nickel, lead, and zinc is related to the bacteria providing the plants with sufficient iron.     

Plant growth-promoting bacteria confer resistance in tomato plants to salt stress.

The object of the work is to evaluate whether rhizobacteria populating dry salty environments can increase resistance in tomato to salt stress. Seven strains of plant growth-promoting bacteria that have 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity were isolated from soil samples taken from the Arava region of southern Israel. Following growth of these seedlings in the presence of 43 mM NaCl for 7 weeks, the bacterium that promoted growth to the greatest extent was selected for further study. DNA analysis of the 16S RNA indicated that the selected bacterium was Achromobacter piechaudii. This bacterium significantly increased the fresh and dry weights of tomato seedlings grown in the presence of up to 172 mM NaCl salt. The bacterium reduced the production of ethylene by tomato seedlings, which was otherwise stimulated when seedlings were challenged with increasing salt concentrations, but did not reduce the content of sodium. However, it slightly increased the uptake of phosphorous and potassium, which may contribute in part to activation of processes involved in the alleviation of the effect of salt. In the presence of salt the bacterium increased the water use efficiency (WUE). This may suggest that the bacterium act to alleviate the salt suppression of photosynthesis. However, the detailed mechanism was not elucidated. The work described in this report is a first step in the development of productive agricultural systems in saline environments.     

巨菌草根部促生菌的筛选及其促生效应

为进一步开发植物促生菌,该研究以巨菌草根部为主要材料进行巨菌草促生菌的筛选,采用解磷、固氮和产IAA等筛选标准对初筛菌株分别进行多项促生能力的测定。通过形态观察、生理生化特性和16S rDNA序列同源性分析对促生效果最好的菌株YB-07进行分类和鉴定,分别测定其促生能力后从中筛选出促生效应强的11个菌株进行盆栽试验,并通过对这些菌株单独回接和多菌混接的小麦盆栽试验测定其对小麦的促生效应。结果表明:从巨菌草根部分离得到了101株促生菌株,分类鉴定结果显示菌株YB-07归属于根瘤菌属(Rhizobium),其溶磷量为20.1 mg·L^-1、产IAA量为23.7mg·L^-1,同时具有产氨能力。盆栽试验测定结果显示,多菌混合接种对小麦的促生效应在株高、干重、鲜重和叶绿素含量上,分别较对照组增加了24.49%、31.84%、28.06%和34.14%。单菌接种对小麦的促生表现在株高、干重、鲜重和叶绿素含量上,分别较对照组增加了13.54%、20.45%、16.84%和35.19%。所筛选到的菌株具有良好的促生长作用,能为进一步构建巨菌草促生菌菌群提供良...     

Plant growth-promoting activities of alkoxycarbonylisoureas in relation to their chemical structures

A number of alkoxycarbonylisourea derivatives were synthesized and their plant growth-promoting activities examined by the rice (Oryza sativa) seedling test. Isourea compounds with an appropriate substituent such as a halogen atom or a methyl, ethyl or methoxy group at the para-position on a benzene ring in 1-alkoxycarbonyl-2-alkyl-3-phenylcarbamoylisoureas promoted the growth of rice seedlings and acted as a highly active gibberellic acid-synergist when used in combination with gibberellic acid. The common structural requirements of isourea derivatives applied well for a growth promoter and a gibberellic acid-synergist.     

Plant growth-promoting bacteria and nitrate availability: impacts on root development and nitrate uptake

Plant growth-promoting bacteria (PGPB) and NO-3 availability both affect NO-3 uptake and root architecture. The presence of external NO-3 induces the expression of NO-3 transporter genes and elicits lateral root elongation in the part of the root system exposed to the NO-3 supply. By contrast, an increase in NO-3 supply leads to a higher plant N status (low N demand), which represses both the NO-3 transporters and lateral root development. The effects of PGPB on NO-3 uptake and root development are similar to those of low NO-3 availability (concomitant stimulation of NO-3 uptake rate and lateral root development). The mechanisms responsible for the localized and long-distance regulation of NO-3 uptake and root development by NO-3 availability are beginning to be elucidated. By contrast, the signalling and transduction pathways elicited by the rhizobacteria remain totally unknown. This review will compare the effects of NO-3 availability and PGPB on root morphogenesis and NO-3 uptake, in order to determine whether interactions exist between the NO-3-dependent and the PGPB-dependent regulatory pathways.