Morphology and Genetic Diversity of Phragmites australis in Beijing

为探明北京地区芦苇(Phragmites australis)的资源状态和多样性, 实地考察北京主要河流、湿地和水库, 发现北京地区芦苇总生长面积已超过600 hm²。芦苇染色体倍性以八倍体为主, 四倍体次之。在面积较大的湿地内, 八倍体单一芦苇群落占据优势地位; 而在城市的浅河内有形态和遗传性多样的混合种群。研究表明, 植物性状和倍性水平之间无显著相关性。在小清河发现了6种形态各异的芦苇克隆, 均属于叶绿体DNA片段的P单倍型; 其单倍体基因组大小为(0.499±0.019) pg, 变异系数为3.8%。这表明表型与单倍型之间也不具相关性。此外, 发现1个具有变叶特性的芦苇, 将其命名为金条芦苇。北京地区芦苇形态和遗传多样性为研究芦苇基因型与环境适应性之间的关系提供了珍贵的资源。     

北京地区芦苇资源状态及其多样性

为探明北京地区芦苇(Phragmites australis)的资源状态和多样性, 实地考察北京主要河流、湿地和水库, 发现北京地区芦苇总生长面积已超过600 hm²。芦苇染色体倍性以八倍体为主, 四倍体次之。在面积较大的湿地内, 八倍体单一芦苇群落占据优势地位; 而在城市的浅河内有形态和遗传性多样的混合种群。研究表明, 植物性状和倍性水平之间无显著相关性。在小清河发现了6种形态各异的芦苇克隆, 均属于叶绿体DNA片段的P单倍型; 其单倍体基因组大小为(0.499±0.019) pg, 变异系数为3.8%。这表明表型与单倍型之间也不具相关性。此外, 发现1个具有变叶特性的芦苇, 将其命名为金条芦苇。北京地区芦苇形态和遗传多样性为研究芦苇基因型与环境适应性之间的关系提供了珍贵的资源。     

Die-back of Phragmites australis: influence on the distribution and rate of sediment methanogenesis

Methanogenesis was measured during the summer of 1994, in sediment coresand bulk samples from a Phragmites australis wetland in northern Jutland,Denmark. We compared sediment from healthy reed and dying-back reed, andan open lagoon resulting from die-back. Cores revealed variability withdepth and between sites, with the highest rates coinciding with layers oforganic gyttja, and negligible methane production from the underlying sandbase. Methanogenesis rates in the lagoon and die back sites were higher(up to 100–150 nmol h^-1 g^-1dry wt. sediment) than in the healthy reed (50–80 nmolh^-1 g^-1), with the highest rates being recordedfrom May to July. At these times, methanogenesis was markedly temperature-limited; samples incubated at 30 °C anon-limiting temperature, gave rates as high as 200–400nmol h^-1 g^-1 for the lagoon and die-backareas and 150 nmol h^-1 g^-1 for the healthyarea. Addition of 8 mM acetate and H₂/CO₂headspace suggested that both acetate-fermenting andCO₂-reducing bacteria were present. Acetate additions suggested some co-limitation by substrate availability, with acetate limitation occurring in the healthy site during July and in the die-back site during August. Lower rates during August, especially in the healthy area, were associated with low water levels which resulted in more oxidized sediments. The data reveal highly variable methanogenesis in the sediment which, when considered with sediment depths, indicates that sites of Phragmites die-back have significantly greater rates of anaerobic mineralization than surrounding healthy wetland, and may be intense sources of methane.     

四种生态型芦苇叶中离子分布对生境的生理适应

采用X射线微区分析技术 ,测定了 4种生态型芦苇 (Phragmitesaustralis (CaV .)Trin .exSteud .)叶的表皮泡状细胞、叶肉细胞和叶脉维管束鞘细胞离子的含量。结果表明 :沼泽芦苇的鞘细胞内 ,K 、Na 、Ca2 、Mg2 和Cl-分布均较叶肉细胞和泡状细胞高。沙丘芦苇的泡状细胞中Ca2 分布较叶肉细胞和鞘细胞高 ,而Mg2 在其叶肉细胞 ,以及K 、Na 和Cl- 在其鞘细胞内分布均较高。在轻度盐化草甸芦苇的叶肉细胞内分布较多的Na 和Mg2 ,而在鞘细胞内K 、Ca2 和Cl- 的分布均较叶肉细胞和泡状细胞为高。重度盐化草甸芦苇的泡状细胞内Na 和Mg2 的分布较多 ;同样 ,在叶肉细胞中K 、Ca2 和Cl- 的分布也较多。最后 ,讨论了上述各种离子在不同生态型芦苇叶内分布的状况 ,以及与其环境适应的生理意义。     

芦苇生态型研究进展

芦苇生态幅极广,适生于多种生境类型。不同的环境选择压力如水深、盐度、养分、气候等交互影响致使芦苇个体及种群间发生不同程度的分化和变异,形成了形态、生理或遗传上互有差异、异地性的不同生态型。尽管基于芦苇表型变异以及遗传变异进行生态型划分的研究已开展很多,但针对芦苇生态型变异规律及其可能的形成机制的认知仍存在较多分歧。在总结近年来有关芦苇生态型研究文献的基础上,通过对影响芦苇生态型变异的主要因素——环境因素和遗传因素的分析,以期为芦苇生态型的划分及其可能的形成机制提供新的研究思路。(1)空间尺度的选择应成为研究者分析、划分芦苇生态型的首要定位。在较大的地理空间尺度上,高度异质性的生境导致某些性状的变异式样具有相对的不连续性,可作为不同芦苇生态型鉴别与描述的主要依据;(2)在合理的尺度定位、取样设计和统计分析的基础上开展的表型变异研究,及进一步基于种群水平的分子标记研究(分子指纹特征或特有等位基因),可为芦苇生态型的鉴定、划分提供更为可靠的参考数据,并且可以甄别生境差异(环境响应)和遗传变异对芦苇不同生态型分化的贡献;(3)应同时进行不同生态型的特定性状与功能(株高、茎粗、生物量、生理抗逆性、水体污染物净化能力等)的定位,推动优良基因型的选育与扩繁。     

五氯酚厌氧生物降解体系中细菌的多样性分析

为了解五氯酚(PCP)降解过程中参与PCP降解的微生物多样性,本文应用16S rRNA基因克隆文库方法对PCP厌氧生物降解体系中细菌群落的组成和相对丰度进行了研究.结果表明,TM7类群的微生物在整个细菌群落中占有最大丰度(48.6%),检测到的序列与在三氯乙烯污染的地下水中检测的克隆子有一定的序列相似性(93.6%).丰度位居第二的微生物类群为β-变形菌纲(Betaproteobacteria)细菌,其中的一些克隆子(10.8%)与脱氯微生物Dechlorosoma suillum具有极高的序列同缘性(99.7%).此外,也检测到少数Clostridium属[厚壁菌门(Firmicutes)类群]的微生物.克隆文库中发现许多序列(占整个克隆文库的51.3%)与GenBank中已报道的序列具有较远的同源性(小于93.4%),它们可能代表新的微生物.本研究进一步拓宽了对PCP降解微生物多样性的认识.     

黄河三角洲3种生境下的芦苇形态差异及生理生态特征研究

为阐明3种自然生境下的芦苇适应环境策略,通过设置样地,研究水生、湿生、旱生生境下芦苇的形态性状及生理生态特征,结果表明：（1）芦苇的最高高度、平均高度、最高冠幅、平均冠幅和盖度以水生生境最大,湿生生境次之,旱生生境最小;多度值以旱生和水生生境条件下较大;在水生条件下,芦苇往往形成单优势种群。（2）3种生境中的芦苇横走茎主茎长度不同,随地下水位下降,各分支无性系分株数量、分株高度和叶片数增多,分株距离、分株直径和叶面积减小;随着水分限制的加强,芦苇的节数和根数量增多,节长和根长变短。（3）在旱生生境下,根部和叶部SOD、POD活性和根部CAT活性显著高于水生和湿生,叶部CAT活性旱生显著低于水生。3种生境叶部MDA含量表现为旱生 > 湿生 > 水生,湿生和旱生生境下,根部MDA含量明显高于水生。这些形态性状的差异及生理生态特征可以看作芦苇对3种生境的适应性表现。     

有机螯合剂在芦苇富集转运铅中的作用

近年来,随着人口的激增和工农业生产的迅猛发展,土壤和水体的重金属污染日益加重。植物提取技术作为一种新兴的修复重金属污染的治理方法,以其潜在的高效、经济及其生态协调性等优势被广泛关注。其研究主要是利用对某些重金属具有超富集能力的超积累植物或耐性植物,配合添加一定量的鳌合剂来进行修复。由于超富集植物一般生长缓慢且生物量小,因此利用对重金属有一定耐性的生长快速、生物量大的植物来进行修复更具有广阔的应用前景。芦苇作为一种多年生禾本科植物,具有生物量大、耐受性强和分布广泛的特点,已经被研究和应用到环境治理的多个领域。本文通过户外盆栽沙培试验,研究了铅胁迫下,分别在 2-10 mmol·L-1共 5 个浓度梯度的 EDTA 和柠檬酸两种鳌合剂处理下,芦苇生长对铅的响应以及对铅在植物体内的富集转运的影响。初试结果表明∶在 4mmol·L-1 Pb(NO3)2胁迫下,施加 EDTA 对芦苇的生长具有一定的抑制作用。当 EDTA 浓度为 10 mmol·L-1 时,透灌 7 d 后,其芦苇根和地上部(茎和叶)干重分别是空白试验(未加螯合剂)的 68.0% 和 72.3%,而柠檬酸对植物生物量的影响较小。同时,EDTA 和柠檬酸对铅在芦苇体内的富集和转运,都起到了促进作用。分别施加 10 mmol·L-1的 EDTA 和柠檬酸,其植物根部和地上部的铅浓度分别为空白试验的 7.4 倍、10.7 倍、2.5 倍、3.5 倍。EDTA 在促进植物体内铅的吸收和从根部到地上部的转运效率方面要比柠檬酸更为有效。尽管像 EDTA 和柠檬酸这样的鳌合剂能够在一定程度上提高植物的富集效率,但考虑到螯合剂自身对植物的毒害性、对环境的潜在威胁以及运行成本等方面因素,目前,寻找高效、廉价、可生物降解的鳌合剂以及大生物量的耐性植物成为植物提取技术的研究重点。     

东北地区芦苇植硅体的变化特征

深入研究芦苇(Phragmites australis)不同生长期植硅体的形态变化规律, 对提高古植被重建精度、探讨植硅体形成机理具有重要意义。该文对东北地区12个样点的芦苇叶片进行研究, 选取长势相近、叶片大小一致的芦苇叶片, 用湿式灰化法提取植硅体并对其进行分类和命名。研究发现, 芦苇植硅体主要有5种类型, 在不同生长期内和不同温湿度组合下, 其植硅体类型组合基本无变化, 说明同种植物的植硅体类型组合具有稳定性, 据此可以有效地恢复古植被; 同时芦苇鞍型植硅体百分含量的峰值出现在7月份, 随后稍有减少, 而芦苇扇型植硅体百分含量和浓度的峰值出现在8或9月份, 谷值在7月份。由此推测芦苇鞍型植硅体的形成可能更多地受控于植物的光合作用和蒸腾作用, 芦苇扇型植硅体的形成可能与机动细胞的支撑作用关系密切。实验结果还表明芦苇植硅体浓度并不是随着时间逐渐积累的, 其在8月份达到峰值, 9月份达到谷值, 因此推测植物植硅体浓度的变化规律可能与植物在不同生长期其自身对硅的需求规律相一致。鞍型植硅体浓度的峰值也出现在8月份, 谷值也在9月份, 其浓度变化与芦苇植硅体总浓度的变化趋势相似。     

扎龙芦苇湿地生长季的甲烷排放通量

为研究高寒地区天然淡水芦苇湿地的甲烷排放特征,采用静态箱-气相色谱法,测定了扎龙不同水位芦苇湿地生长季的甲烷排放通量.结果表明:观测期内,扎龙芦苇湿地甲烷排放通量平均为7.67 mg·m^-2·h^-1（-21.18～46.15 mg·m^-2·h^-1）,其中深水区(平均水深100 cm)和浅水区(平均水深25 cm)的平均甲烷排放通量分别为5.81和9.52 mg·m^-2·h^-1,排放峰值分别出现在8月和7月,最低值均出现在10月.深水区夏季(6-7月)的甲烷排放通量显著低于浅水区,而春(5月)、秋(8-10月)季节显著高于浅水区.生长季甲烷排放通量的变化为夏季>秋季>春季;昼夜排放量为12:00和14:00最高,0:00最低.温度和水位是高寒地区淡水芦苇湿地甲烷排放通量变化的主要影响因子.     

Decomposition dynamics of Phragmites australis litter in Lake Burullus,Egypt

This study estimated the decomposition rate and nutrient dynamics of Phragmites australis litter in Lake Burullus (Egypt) and investigated the amount of nutrients released back into the water after the decomposition of the dead tissues. Phragmites australis detritus decomposition was studied from April to September 2003 utilizing the leaf, stem, and rhizome litterbags technique with coarse mesh (5 mm) bags on five sampling dates and with nine replicate packs per sample. All samples were dried, weighed and analyzed for N, P, Ca, Mg, Na, and K concentrations. The exponential breakdown rate of leaves (?0.0117/day) was significantly higher than that of rhizomes (?0.0040/day) and stems (?0.0036/day). N, Na and K mineralization were the highest from leaf litter, followed by rhizomes and stems, while P, Ca and Mg mineralization were the highest from rhizomes, followed by leaves and stems. The dead shoot biomass at the end of 2003 amounted to 4550 g DM/m² which enters the decomposition process. By using the decay rate of 0.0117 and 0.0036/day for the leaves and stems, 3487 g DM/m² is decomposed in a year, leaving only 1063 g DM/m² after 1 year. This is mainly equivalent to releasing the following nutrients into surrounding water (in g/m²): 24.4 N, 1.1 P, 15.5 Ca, 3.5 Mg, 11.3 Na and 16.7 K. In conclusion, the present study indicates a significant difference in relation to the type of litter; these breakdown rates were generally greater than most rates reported in previous studies that used the same technique and mesh size.     

Common Reed Phragmites australis: Control and Effects Upon Biodiversity in Freshwater Nontidal Wetlands

Phragmites australis (common reed) has expanded in many wetland habitats. Its ability to exclude other plant species has led to both control and eradication programs. This study examined two control methods—herbicide application or a herbicide‐burning combination—for their efficacy and ability to restore plant biodiversity in non‐tidal wetlands. Two Phragmites‐dominated sites received the herbicide glyphosate. One of these sites was burned following herbicide application. Plant and soil macroinvertebrate abundance and diversity were evaluated pre‐treatment and every year for four years post‐treatment using belt transects. The growth of Phragmites propagules—seeds, rhizomes, and rooted shoots—was examined in the greenhouse and under bare, burned, or vegetated soil conditions. Both control programs greatly reduced Phragmites abundance and increased plant biodiversity. Plant re‐growth was quicker on the herbicide‐burn site, with presumably a more rapid return to wetland function. Re‐growth at both sites depended upon a pre‐existing, diverse soil seed bank. There were no directed changes in soil macroinvertebrate abundance or diversity and they appeared unaffected by changes in the plant community. Phragmites seeds survived only on bare soils, while buried rhizomes survived under all soil conditions. This suggests natural seeding of disturbed soils and inadvertent human planting of rhizomes as likely avenues for Phragmites colonization. Herbicide control, with or without burning, can reduce Phragmites abundance and increase plant biodiversity temporarily. These changes do not necessarily lead to a more diverse animal community. Moreover, unless Phragmites is eradicated and further human disturbance is prohibited, it will likely eventually re‐establish dominance.     

Isoprene emission and primary metabolism in Phragmites australis grown under different phosphorus levels

Aquatic plants are generally used for wastewater purification and phytoremediation, but some of them also emit large amounts of isoprene, the most abundant biogenic volatile organic compound. Since isoprenoid biosynthesis requires high amounts of phosphorylated intermediates, the emission may also be controlled by inorganic phosphorus concentration (Pi) in leaves. We carried out experiments to determine the emission of isoprene from Phragmites australis plants used in reconstructed wetlands to phytoremediate elevated levels of phosphorus contributed by urban wastes. Four groups of plants were grown hydroponically in water containing different levels of KH(2)PO(4). High levels of phosphorus in the water resulted in high Pi in the leaves. High Pi stimulated photosynthesis at intercellular CO(2) concentrations lower and higher than ambient, implying higher ribulose 1,5-bisphosphate carboxylase (Rubisco) activity and higher ribulose 1,5-bisphosphate regeneration rates, respectively. However, isoprene emission was substantially lower at high Pi than at low Pi, and was not associated to photosynthesis rates at high Pi. This surprising result suggests that isoprene is limited by processes other than photosynthetic intermediate availability or by energetic (ATP) requirements under high Pi levels. Irrespective of the mechanism responsible for the observed reduction of isoprene emission, our results show that Phragmites plants may effectively remove phosphorus from water without concurrently increase isoprene emission, at least on a leaf area basis. Thus, Phragmites used in reconstructed wetlands for phytoremediation of urban wastes rich of phosphates will not contribute high loads of hydrocarbons which may influence air quality over urban and peri-urban areas.     

扎龙芦苇遗传多样性ISSR分析

采用ISSR分子标记技术对扎龙湿地的5个野生芦苇居群进行了遗传多样性研究.从75条ISSR引物中筛选出10个特异性强、稳定性好的引物进行ISSR分析.共获得96个位点,其中多态位点94个,多态位点百分率为97.92％.PopGene分析结果表明:居群的平均多态位点百分率为56.46％,Shannon's多样性指数(J)...     

用芦苇恢复受损河岸生态系统的工程化方法

我国中小河流的护岸工程只考虑工程的耐久性多采用混凝土护岸。忽略了河流的生态功能,破坏了河流的各种生态过程,导致河流污染严重,生态作用越来越小。本研究提出一种用芦苇恢复受损河岸的工程化方法,以解决恢复受损河岸时成本高,破坏了芦苇原生地的生态环境和芦苇不便于运输的问题。其优点在于：在保证能够达到防止河岸崩塌及侵蚀的同时,在河岸工程设计中纳入生态学原理．创造出动植物及微生物能够生存的多孔隙河岸工程生态结构;可以减少对芦苇原生地的破坏。并且能够快速、大量繁殖芦苇幼苗。快速恢复受损河岸的芦苇群落及其生态环境;此方法在减少劳力、时间和成本的基础上,能够更容易恢复浅水带和河岸缓冲带芦苇群落,构建出一个芦苇繁茂的水域。     

Some Aspects of the Importance of Genetic Diversity in Phragmites australis (Cav.) Trin. ex Steudel for the Development of Reed Stands

Various sites of Phragmites australis in Germany (Uckermark and Mark Brandenburg) and sites in Hungary and Denmark were investigated by PCR fingerprinting in order to determine their genetic diversity. Genetic similarities were calculated and, based on this, a cluster analysis was performed. The genetic similarity of reed clones around one lake ranged from between 70 to 100%, that of clones from different lakes was clearly lower. The further apart the clones were situated from each other, the less similar they were. At a wetland site near the shore a sudden colonisation by several new Phragmites clones was observed. This site was located in front of a well established genetically almost homogenous stand within the eulittoral. All the results are discussed in connection with a proposed model of establishment and development of water reed stands: colonization, selection of best adapted clones by competition and the stability of stands.     

昭苏县野生羊肚菌根际土壤细菌多样性研究

采集昭苏县野生羊肚菌(Morchella esculenta)根际水平直径10 cm、深度0～30 cm范围内的3层各10 cm土壤样品,利用Illumina miseq 2×300 bp高通量测序技术和生物信息学分析方法检测细菌类群的多样性。结果显示,细菌群落Chao和Shannon指数在0～30 cm土层中的平均值分别为152和3.68,且两种指数在10～20 cm土层均最高;细菌群落在各分类水平上的类群(最大类群丰度)分别为变形菌门(Proteobacteria,36.3%)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)等13门;黄杆菌科(Flavobacteriaceae,8.4%)、芽胞杆菌科(Bacillaceae)和葡萄球菌科(Staphylococcaceae)等43科;葡萄球菌属(Staphylococcus,7.1%)、杆状菌属(Bacillus)和Cloacibacterium等52属;不能培养的α-变形杆菌(uncultured α-proteobacterium,2.0%)、不能培养的嗜甲基菌科1种(uncultured Methylophilaceae bacterium)和路西法芽胞杆菌(Bacillus luciferensis)等44种。检测到固氮菌32属,包括15属自生固氮菌、9属共生固氮菌和8属联合固氮菌。结果表明,羊肚菌土壤根际微生物样品中细菌类群具有多样性,10～20 cm土层根际微生物多样性较高,但很多种类丰度较低;该土样含有丰富的固氮菌,这对栽培羊肚菌如何选地或覆土具有一定的指导意义。     

中国滨海沼泽湿地芦苇种子功能性状的纬度梯度变异

种子功能性状反映了植物适应环境变化的繁殖对策,这是植物在自然环境选择和遗传上的一种进化行为,对深入认识植物及种子对环境的长期适应性进化意义重大。本研究对中国滨海6个省市9个地区的滨海沼泽湿地(21°29′—40°57′ N)主要土著植物芦苇种子功能性状(包括种子大小、重量、结实率和产量)进行研究,分析其纬度变异规律。结果表明: 我国滨海湿地芦苇种子各功能性状在不同纬度差异显著,各功能性状间具有显著的相关性。芦苇种子大小(种长、种宽、种形指数、长宽比、种子表面积)和百粒重与纬度呈显著的二次函数关系,随着纬度升高先降后升,而种子结实率呈现先升后降的规律,芦苇种子数量与大小间存在着权衡关系。单位面积种子产量随着纬度升高显著增加。逐步回归分析显示,气候因素是影响不同纬度间芦苇种子功能性状差异的主要因素,土壤孔隙水的pH和盐度次之。