科研快讯

《植物与细胞生理学》:研究阐明浒苔对环境胁迫响应分子机制近日,中国科学院海洋研究所的研究人员在浒苔生物学研究取得重要进展,阐明了浒苔对环境胁迫响应的分子机制和"绿潮"发生时漂浮浒苔的生理状,为全面认识由浒苔引发的海洋"绿潮"现象提供了重要理论基础。相关研究成果发表在在国际期刊《植物     

《植物与细胞生理学》：研究阐明浒苔对环境胁迫响应分子机制

近日,中国科学院海洋研究所的研究人员在浒苔生物学研究取得重要进展,阐明了浒苔对环境胁迫响应的分子机制和“绿潮”发生时漂浮浒苔的生理状,为全面认识由浒苔引发的海洋”绿潮”现象提供了重要理论基础。相关研究成果发表在在国际期刊《植物与细胞生理学》（Plantand Cell Physiology）上。     

植物干旱胁迫响应机制研究进展——从表型到分子

干旱胁迫是抑制植物生长发育的主要限制因子之一,植物为适应干旱的外界环境,会依据自身的习性启动响应机制。从植物外部形态、生理代谢、生化过程、细胞及分子水平的变化阐述了植物对干旱胁迫的响应机制,详细阐述了生理及分子水平的响应机制,并对分子和遗传水平的响应机制和植物抗旱性关系的未来研究方向提出了展望,以期为植物抗逆性及遗传育种研究提供参考。     

周丛藻类及其在水质净化中的应用

周丛藻类广泛存在于自然界水体中,具有生物量大、生态功能强、水质响应灵敏等特征.周丛藻类通过吸收代谢利用、吸附和络合等过程去除水体污染物质,用于水质净化,具有耐污能力强,N、P去除效果好,藻类细胞回收利用价值高等优点,推广应用前景广阔.近年开发的藻丛刷系统、周丛藻类 生物膜系统和周丛藻类水产养殖系统等已经成功用于畜禽水产养殖废水、生活污水处理.而周丛藻类的生存规律、对污染物浓度的生理响应机理和污染物质吸收利用的分子生物学机制仍有待进一步研究.     

新疆塔里木河下游生态输水与胡杨叶片的生理及形态响应

选择塔里木河下游3个典型断面的15个研究样地,分析和测定了塔里木河下游2000￣2002年生态输水前后不同研究样地的地下水位、地下水含盐量和胡杨(Populus　euphratica　Oliv.)叶片中脯氨酸、可溶性糖、植物内源激素脱落酸和细胞分裂素的含量以及胡杨叶片的形态结构变化,研究了塔里木河下游主要建群种胡杨对生态输水的生理与形态的响应和适应性。结果表明,塔里木河下游胡杨生长已受到不同程度的干旱胁迫;输水后各样地地下水位均有所上升,胡杨对浅层地下水位的变化表现出明显响应,胡杨受到的生理胁迫降低,胡杨叶片角质层厚度、维管束导管官腔直径及管壁厚度皆随地下水位的上升而减少;随着地下水位的上升,地下水含盐量分别提高1.76　￣　2.47倍,输水效果由于盐对植物的生理胁迫作用的增加而有所减弱;在塔里木河下游极端干旱环境下,胡杨林保育恢复的合适地下水位埋深为3.15　￣　4.12　m,地下水含盐量为67.15　￣　72.65　mm。     

新疆塔里木河下游生态输水与胡杨叶片的生理及形态响应

选择塔里木河下游3个典型断面的15个研究样地,分析和测定了塔里木河下游2000～2002年生态输水前后不同研究样地的地下水位、地下水含盐量和胡杨(Populus euphratica Oliv.)叶片中脯氨酸、可溶性糖、植物内源激素脱落酸和细胞分裂素的含量以及胡杨叶片的形态结构变化,研究了塔里木河下游主要建群种胡杨对生态输水的生理与形态的响应和适应性.结果表明,塔里木河下游胡杨生长已受到不同程度的干旱胁迫;输水后各样地地下水位均有所上升,胡杨对浅层地下水位的变化表现出明显响应,胡杨受到的生理胁迫降低,胡杨叶片角质层厚度、维管束导管官腔直径及管壁厚度皆随地下水位的上升而减少;随着地下水位的上升,地下水含盐量分别提高1.76～2.47倍,输水效果由于盐对植物的生理胁迫作用的增加而有所减弱;在塔里木河下游极端干旱环境下,胡杨林保育恢复的合适地下水位埋深为3.15～4.12 m,地下水含盐量为67.15～72.65 mm.     

浮游植物孢囊的研究进展与生态意义

浮游植物具有复杂的生活史。与陆生植物的休眠细胞类似,孢囊是浮游植物生命过程中重要的一环,它在抵抗外界压力、应对不良环境、维持生理稳态、维护物种繁衍等方面具有重要意义。在一些生态事件中,更有人提出孢囊是藻类周期性暴发的种子库。然而,相比于成熟细胞,孢囊的生态生理学研究还相对缺乏。为了加深对孢囊生命过程和生态意义的认识,我们以近20年的文献为重点梳理了浮游植物孢囊研究的最新进展。概述了典型浮游植物甲藻、硅藻孢囊(休眠孢囊、游动孢囊、成熟孢囊)的类型及形成因素,总结了孢囊的形成机制、生理特征和萌发要素,并阐释了孢囊在藻类进化和海洋碳循环中的意义。本文旨在总结孢囊的适应性和可塑性,加深对藻类生存策略的生态学机制的认识。     

植物对低温的光合响应

低温是影响植物生长和发育的主要环境因子之一.低温下,植物的许多生理生化过程受到影响,而其中光合作用是对低温最敏感的过程.光合作用是地球上最重要的生理生化过程,所以研究光合作用在低温下的响应机制具有重要意义.本文系统地总结了当前国内外最新研究进展,综述了低温下植物的光合响应,主要内容包括影响低温下光合响应的因素、低温下光合响应的关键问题--能量平衡的调节,以及植物的低温光合响应信号通路,并展望了低温光合响应研究的新方向.     

微囊藻群体形成影响因子及机理

富营养化导致的湖泊、水库蓝藻水华带来了一系列环境和生态问题。微囊藻群体形成,在水体表面的聚集是形成水华的重要策略之一。微囊藻群体形成有效抵御了草食性动物摄食、病毒、细菌的侵害,耐受不良环境因子(紫外辐射、高光强、重金属等)能力显著增强。文章探讨了野外微囊藻群体占优势的机制并综述了影响微囊藻群体形成的外源因子及作用机理,包括非生物因子(营养、温度、光照、重金属、微囊藻毒素、乙醛酸)、生物因子(草食性动物、细菌、鱼类、藻类)。基于现有研究,本综述还对未来研究进行展望:(1)非生物因子与生物因子协同效应对藻类形态影响研究; (2)人类活动对浮游藻类形态及动态的影响研究;(3)藻类形态对沉水植物的响应在未来淡水生态系统修复中的应用; (4)促进藻类群体形成的胞外多糖分泌在未来工业生产中的作用。     

C_4植物玉米的光合-光响应曲线模拟研究

光是植物光合作用最基本的一个决定因子,准确分析光响应曲线及其参数是研究光合生理生态过程对环境变化响应的重要途径;但相关模型及其模拟的准确性仍待改进。该研究基于C_4作物玉米(Zea mays)不同干旱处理试验资料,比较研究了现有光响应模型(直角双曲线模型、非直角双曲线模型、直角双曲线修正模型、指数模型、二次函数模型以及新提出的改进模型)的适应性。结果表明,改进的光响应模型具有较好的精确度,可较准确地描述光响应曲线,也能够准确拟合最大净光合速率、光饱和点、光补偿点以及暗呼吸速率4个关键光合参数。该结果为研究植物光合生理生态过程及其环境适应性提供了一个改进的模拟方法。     

溶藻细菌的生态学作用及其生物量检测方法

有害藻类水华已成为当今世界水体普遍存在的环境问题,溶藻细菌作为水华和赤潮防治的可能生物,引起了众多科研人员的关注。介绍了溶藻细菌的研究概况,重点对溶藻细菌的生态学作用及其生物量的检测方法进行了综述。     

赤潮过程中“藻-菌”关系研究进展

微生物对促进海洋物质循环,维持水生环境的生态平衡具有重要作用。在赤潮事件中,基于微生物(尤其是细菌)的多样性和重要性,它们与藻类之间的相互关系成为了研究的热点。过去20年里,人们从不同角度对"藻-菌"间的关系进行了探索,包括物理学过程、生物学过程、环境过程以及化学过程。就化学过程而言,它作为一种较早出现的技术,在以往的研究中带给人们许多认识藻菌关系的方法。随着学科的渗透,化学法有了拓展与延伸,为人们认识藻菌关系带来了新的契机。从化学生态学领域来梳理"藻-菌"关系中涉及的现象和行为,包括菌对藻的有益面、菌对藻的有害面、以及藻类应答细菌行为的化学途径;并从信号语言(群体感应、化感作用)的角度来阐释两者之间的互生或克生关系。通过文献综述的方式来解读藻菌关系的互作过程和机理,为认识赤潮的发生和防控方法提供借鉴。     

‘Green tides’ are overwhelming the coastline of our blue planet: taking the world’s largest example

A broad spectrum of events that come under the category of green tide are recognized world-wide as a response to elevated levels of seawater nutrients in coastal areas. Green tides involve a wide diversity of sites, macroalgal species, consequences, and possible causes. Here we review the effect of natural and man-induced environmental fluctuations on the frequency and apparent spread of green tides. This article highlights the need for interdisciplinary research aimed at shedding light on the basic mechanisms governing the occurrence and succession of green algae in coastal seas. This will result in more effective management and mitigation of the effects of green tides, thus safeguarding the intrinsic and commercial value of coastal marine ecosystems.     

光强和温度变化对曲浒苔光合作用的调节机制

实验针对曲浒苔(Ulva flexuosa)光合作用系统对光照与温度变化的响应进行分子水平探究, 从原初反应、电子传递、光合磷酸化到碳的固定等方面对曲浒苔光合作用响应机制进行解析。叶绿素合成基因在高温高光[30℃、400 μmol/(m2·s)]环境下表达下调。类胡萝卜素合成基因在低温高光[4℃、400 μmol/(m2·s)]环境下表达下调。电子传递链、CF₁F₀-ATP合酶等基因对温度和光照变化的适应能力较弱, 各实验组的相关基因表达量均呈现下调趋势。聚光复合体基因表达量上调。各实验组的光系统Ⅱ反应中心基因均下调, 锰稳定蛋白则普遍上调。不同C₄途径关键酶基因在各个环境中的变化趋势不一致。综合实验结果可以发现曲浒苔对于温度和光照变化具有一定的耐受度, 分析得出温度对曲浒苔光合作用基因的影响较大, 而且高温高光对曲浒苔的影响最显著。     

Responses of spring phytoplankton communities to their habitats in the Xiangxi Bay of Three Gorges Reservoir,China

Since the water storage was initiated in 2003, the environment of Three Gorges Reservoir (TGR) has changed significantly. Algal blooms and eutrophication have been a frequent occurrence, with serious eutrophication in the tributary bays. To provide some theoretical evidence for the prevention and control of algal blooms, the goal of this study is to elucidate factors that influence algal blooms at different sections of the Xiangxi Bay (XXB). Using field data from the XXB, the responses of phytoplankton communities to their habitats were investigated from March to May, 2010. The results indicated a significant spatial and temporal heterogeneity in phytoplankton composition, cellular abundance, and habitats in the spring. Fifty-four genera representing 6 phyla were monitored. Redundancy analysis indicated that the variation in water temperature and relative water column stability (RWCS) contributed greatly to the succession of spring phytoplankton. Due to different physiological adaptabilities and mechanisms of competition among the algae species, significant succession of the community structure had been observed. The predominant species appears to have changed from those adapted to low temperatures and strong mixing (dinoflagellates and diatoms) to those adapted to high temperatures and weak mixing (green algae and cyanobacteria). The lack of silicate resulted in the succession from diatoms to green algae. Due to the influence of the Yangtze River, there is a low potential for algal blooms at lower reaches of the bay because of frequent water exchange. In contrast, the potential is high at middle and upper reaches where the water temperature increases gradually. The hierarchical status of the two sections is significantly different. Precipitation would inhibit algal blooms somewhat, and heavy rainfall would eliminate algal blooms throughout the bay. Phytoplankton are sensitive to their changing habitat in XXB. For a bloom to occur, sufficient nutrients, a lower flow velocity, and appropriate temperature and light conditions are necessary. As an artificial regulating reservoir, proper ecological regulation could not only significantly affect the dynamic conditions of the water body tributaries, but it could also change the transfer characteristics of light and heat, abolishing the algae habitats and thereby inhibiting the water bloom.     

浒苔干粉末提取物对东海原甲藻和中肋骨条藻的克生作用

研究不同溶剂的浒苔干粉末组织提取液对两种赤潮藻—东海原甲藻和中肋骨条藻生长的克生效应。结果表明, 浒苔提取物中确实含有可以影响赤潮藻类生长的克生物质,克生作用具有较明显的浓度效应,添加浓度低时可能会表现为一定的促进生长的作用,添加浓度较高时表现为抑制作用,添加浓度越大,抑制作用越强,即“低促高抑”的特点,这与浒苔提取物对其他微藻的作用相似。其中,蒸馏水提取物对这两种赤潮藻的克生作用小于有机溶剂提取物,有机溶剂中,甲醇和乙酸乙酯提取物对这两种赤潮藻的克生效果最好,正己烷相对较差。根据相似相溶原理,可以初步推断最有效的克生物质应为具有相对较高的极性的有机物。两种赤潮藻对克生物质的敏感程度不同。东海原甲藻对克生物质的敏感性高于中肋骨条藻。蒸馏水、甲醇、乙酸乙酯、正己烷的浒苔干粉末提取物影响东海原甲藻生长的致死作用阈值浓度分别为5.00 g/L、0.50 g/L、0.50 g/L、0.63 g/L（相当于浒苔新鲜藻体浓度为22.00 g-wet/L、2.20 g-wet/L、2.20 g-wet/L、2.75 g-wet/L）;影响中肋骨条藻生长的致死作用阈值浓度则分别为20.00 g/L、1.25 g/L、1.25 g/L、2.50 g/L（相当于新鲜藻体浓度为88.00 g-wet/L、5.50 g-wet/L、5.50 g-wet/L、11.00 g-wet/L）。     

赤潮藻毒素生物合成研究进展

合成毒素是赤潮藻类的一个常见特征,已知能够产生毒素的微藻有70多种。作为次级代谢产物,藻毒素的产生可能是一种压制或清除其它藻类竞争者的一种反应,在群落演替、种间竞争中发挥重要作用。目前,人们对藻毒素生物合成机理依然知之甚少,相关基因的研究仍无明显突破。利用环境因子诱导毒素生成变化进而分离差异表达基因或者比较不同产毒藻株间基因表达的差异,从中克隆藻毒素生物合成基因似乎是一种极具潜力的研究方向。     

The grassland of Orkney: An œcological analysis

Summary

World-wide, our coastal waters have been subject to an increased nutrient input since the latter part of the nineteenth century. This has led to the eutrophication or ‘nutrient pollution’ of many coastal sites, including Langstone Harbour and the Ythan Estuary here in the UK. Eutrophication at these and, indeed, at other nutrient enriched sites is evident by the appearance of large blooms of fast-growing opportunistic macroalgae. Blooms of macroscopic species of green algae (Chlorophyta: Ulvophyceae) are particularly common and the phenomenon is often referred to as the occurrence of green tides.

Green tides may have a dramatic environmental impact, causing much damage to the local ecosystem. Numerous strategies have hence been employed in order to combat the problem, but to date there has been limited success. For this reason, current research in the UK is aimed at increasing our knowledge of green tide algae in terms of their ecophysiology, whilst further investigation of the nutrient pathways and fluxes within specific ecosystems has been deemed necessary. It is anticipated that this ‘backto basics’ approach will ultimately contribute to the development of new, successful eutrophication management strategies.     

The effects of a harmful alga on bivalve larval lipid stores

Marine invertebrates often have complex life histories that include a swimming planktivorous larval stage, at which time they are vulnerable to a variety of stressors, including those associated with nutritional stress and harmful algal blooms. Lipid stores have been shown to be especially important for post-metamorphic survivorship and growth in a variety of marine invertebrates. We investigated the effects of the harmful brown tide alga Aureococcus anophagefferens on the lipid stores and growth of larvae of the hard clam (northern quahog, Mercenaria mercenaria), a dominant bivalve in many western Atlantic bays and estuaries. M. mercenaria was the dominant bivalve in Great South Bay, Long Island, until the mid-1970s, but very few larvae are presently found in these waters. Recent brown tide blooms have been hypothesized to pose a barrier to recovery of M. mercenaria populations and hinder recent restoration efforts by negatively affecting clam larvae. To test whether a diet of the brown tide alga affects the accumulation of beneficial lipid stores, we fed larvae one of three diets representing equal biovolumes of Isochrysis galbana, a nutritious control alga; A. anophagefferens, the brown tide alga for which nutritional quality is not presently known; or a mixture of the two. Larvae fed only brown tide had significantly less lipid stores than those in the other dietary treatments. In addition, brown tide negatively affected larval size. We also tested for evidence of tradeoffs between larval growth and lipid stores, predicting that when the diet was less nutritious as in the brown tide treatments, larval size and lipids would be negatively correlated. In contrast, we found that larvae fed a mixed algal diet or only A. anophagefferens showed a significant positive correlation between lipid stores and size, suggesting that some larvae were simply better at obtaining food and associated nutrients. Larval success likely depends on a complex interplay between genetic and environmental factors. Our study suggests that poor nutrition associated with a harmful alga can have negative effects on larval size and lipids stores, which in turn are mediated by the inter-individual variability in the ability to grow and accumulate necessary lipid stores. Phytoplankton quality is likely to be important for the sustainability of bivalve populations even when it primarily impacts the larval phase; and a diet of brown tide algae may have lasting legacies for juveniles and adults.