喜钙和嫌钙植物对外源Ca2+的生长生理响应

以喜钙植物伞花木和嫌钙植物大白杜鹃为实验材料,以Hoagland营养液并设置其Ca2+浓度分别为0、5、10、25、50mmol/L培养试验,比较不同浓度外源Ca2+对其生长、叶绿素含量、渗透调节和矿质元素积累的影响,探索喜钙植物生长的适应特征,为喀斯特地区喜钙植物嗜钙机制研究提供基础资料。结果显示:(1)随着外源Ca2+浓度的增加,伞花木植株高度、茎粗以及叶干重、叶长、叶宽和叶形指数均得到不同程度提高,叶绿素和可溶性蛋白质含量增加,脯氨酸和可溶性糖含量无显著变化;而嫌钙植物大白杜鹃的生长却受到抑制,叶绿素和蛋白质含量降低,脯氨酸和可溶性糖含量增加;当Ca2+浓度为50mmol/L时,伞花木叶绿素和蛋白质含量分别为2.99mg/g和17.10mg/g,大白杜鹃叶绿素和蛋白质含量分别为1.39mg/g和14.30mg/g。(2)在实验设置的钙范围内,Ca2+可促进伞花木对P、N吸收并稳定体内Ca、K动态;而低浓度的Ca2+(<10mmol/L)促进大白杜鹃对Ca累积,抑制N、P吸收。     

鼎湖山南亚热带常绿阔叶林植物和土壤微量元素含量

报道了鼎湖山南亚热带常绿阔叶林各层次植物和表层土壤(0～20 cm)四个微量元素(Cu、Fe、Mn和 Zn)的含量和分配格局。结果表明:(1)土壤有效Cu、Fe、Mn和Zn含量(mg／kg)平均值依次为0．72、140．85、 1．42和1．92;(2)所有植物叶片Cu、Fe、Mn和Zn元素含量(mg／kg)分别介于6．1～100．6、6．5～1027．5、46．3 ～1196．7和27．0～338．6,其中乔木层植物叶片微量元素含量(mg／kg)平均值表现为Mn(305．3)>Fe (259．3)>Zn(109．9)>Cu(19．3),而其它植物表现为Fe(586．4)>Mn(336．9)>Zn(141．4)>Cu(36．6);(3) 植物微量元素在各器官的分配格局随元素和植物所在的层次不同而异:乔木层植物Cu含量高低排序为干> 根>枝>叶>皮,Fe为根>皮>叶>枝>干;Mn为叶>皮>枝>根>干;Zn为叶>根>枝>皮>干;(4)在 群落垂直结构上,Fe元素含量表现为自上而下递增的趋势,而Cu、Mn和Zn含量规律不明显;(5)植物和土壤 的微量元素与微量元素间相关性均较差;(6)与亚热带其它森林相比,鼎湖山季风常绿阔叶林土壤Cu、Mn和 Zn含量较低,但乔木层植物因具有很强的吸收或富集能力而含量较高。     

泉州常绿阔叶林的特征与分布

泉州的常绿阔叶林包括南亚热带雨林和南亚热带山地照叶林。通过对这两种植被类型的区分成分、生活型、叶的性质以及群落的结构与分布的分析,说明海拔450m以下具有较明显的以厚壳桂、红楠等为优势种的南亚热带雨林的特征和景观;海拔450～900m主要以米槠等拷类为优势种的群落,但仍有南亚热带雨林的某些特征;海拔900～1400m以甜槠为主要建群种的群落,属于中亚热带照叶林的群落特征。     

安宁河流域植物、土壤特征与钉螺分布的关系

植物、土壤是日本血吸虫的中间宿主———钉螺孳生繁殖不可缺少的重要条件。对四川凉州地区安宁河流域的血吸虫病流行区内不同环境的植被、土壤特征进行研究,有助于我们进一步了解钉螺孳生的环境特征,以便指导钉螺防治。１研究方法１．１选择安宁河流域土壤浸蚀程度不同...     

南亚热带混交人工林树种丰富度与土壤微生物多样性和群落组成的关系

森林植被与土壤微生物作为森林生态系统的重要组成部分,它们之间的相互作用对维持森林生态系统功能和稳定性起着重要作用。以往多在天然草地和森林生态系统开展植物多样性与土壤微生物多样性关系的研究,但人工构建的多树种混交林生态系统中树种多样性对土壤微生物群落组成的影响及其机制尚不完全清楚。因此,以南亚热带人工块状造林后自然恢复形成的多树种混交森林生态系统为研究对象,利用高通量测序技术研究了随树种丰富度(1—10种)变化土壤细菌和真菌多样性的变化规律及主要影响因子。结果表明,随树种丰富度增加,土壤真菌α多样性显著提高,但土壤细菌α多样性差异不显著;不同树种丰富度梯度间土壤细菌和真菌的群落结构组成均差异显著;Pearson相关分析表明土壤细菌α多样性主要受土壤pH和土壤铵态氮影响,而土壤pH和有效磷是土壤真菌α多样性的主要影响因子。距离冗余分析(db-RDA)表明,对土壤细菌群落组成产生显著影响的环境因子分别为土壤pH、硝态氮和芳香碳组分,而土壤有机碳、硝态氮、细根生物量和氧烷基碳组分是影响土壤真菌群落组成的主要因子。本研究的结果说明了南亚热带人工林不同树种混交后形成多树种混交林生态系统的过程中,树...     

LYCHNOTHAMNUS BARBATUS(轮藻植物)的生态与保护研究

轮藻植物属Lychnothamnus(Rupr．)Leonh．自晚始新世即有化石代表,在上新世繁盛且分布广泛,此后分异度降低、分布范围缩减,延续至今仅存1种：L．barbatus(Meyen)Leonh．。上世纪末叶前该种还曾广泛分布于欧洲、印度、中国、巴布亚新几内亚和澳大利亚,而后该种在澳大利亚曾经留有记录的产地消失,直到1996年才被再次发现。本文描述了澳大利亚L．barbatus的居群特征,包括植株、卵囊球和藏卵器形态特征以及萌发生态学的实验研究结果。讨论该种的野外生态学、共生种、全球范围的分布与丰度特征,探讨该种衰落的原因并提出植物保护方案。     

盐碱草地植物种群分布与土壤营养关系的一种分析方法——土壤营养位分析

基于对松嫩盐碱草地植物种群分布特点及影响植物种群分布格局的生态环境因素的分析,提出了盐碱草地植物种群分布与土壤营养关系的一种分析方法--土壤营养位分析。给出了土壤营养位的计测方法,并讨论了土壤营养位效能指标的选择和土壤营养轴上测定指标的处理。     

海南霸王岭不同森林类型附生兰科植物的多样性和分布

附生兰科植物是热带林附生植物的主要类群之一,对于维持热带林生态系统的物种多样性及生态功能具有重要的作用。以海南岛霸王岭国家级自然保护区内的6种热带原始林类型(热带季雨林、低地雨林、热带针叶林、山地雨林、山地常绿林及山顶矮林)中的附生兰科植物为研究对象,通过样带调查(每个森林类型设置12个10m×50m的样带,记录每个样带内胸径(DBH)≥5cm的树木及藤本上附生兰科植物的物种名称、株数及附生位置)分析了附生兰科植物的物种多样性、附生位置及其在不同森林类型中的分布规律。结果表明:1)3.6hm2森林调查样带内共记录到附生兰科植物9634株,分属于26属60种;2)除趋势对应分析(DCA)结果表明,6种森林类型中的附生兰科植物可分成5组(其中,山地常绿林与山顶矮林内的附生兰科植物归为一组);3)分布海拔范围相临近的森林类型的附生兰科植物具有较高的相似性,山地常绿林和山顶矮林附生兰科植物的相似性最高(88.9%);4)6种森林类型中,较高海拔的3种森林类型(山地雨林、山地常绿林和山顶矮林)中,附生兰科植物的丰富度和多度均显著高于其在较低海拔的3种森林类型(热带季雨林、低地雨林和热带针叶林),其中,附生兰科植物在山地常绿林内的丰富度和多度均最高;5)热带季雨林、低地雨林、热带针叶林及山地雨林内,宿主冠区附生兰科植物的多度均高于干区;山地常绿林内两者之间无显著差异;而山顶矮林干区的附生兰科植物的多度高于冠区;6)调查木上附生兰科植物的发生率在高海拔森林类型均高于其在低海拔森林类型,各森林类型内附生兰科植物的多度及物种丰富度与宿主胸径均存在显著正相关关系。     

南亚热带森林不同演替阶段植物与土壤中N、P的化学计量特征

选择南亚热带森林演替过程3个阶段(初期、中期和后期)的典型森林生态系统为研究对象, 在测定植物与土壤中全N、全P含量的基础上, 阐明了森林演替过程中植物与土壤的N、P化学计量特征。结果显示: 1)土壤中全N含量随演替进行而增加, 马尾松(Pinus massoniana)林(初期)、混交林(中期)和季风林(后期) 0-10 cm土层中全N含量分别为0.440、0.843和1.023 g·kg^-1; 混交林0-10 cm土层中全P的含量最为丰富, 为0.337 g·kg^-1, 马尾松林和季风林土壤全P含量分别为0.190和0.283 g·kg^-1。2)植物叶片中全N、全P的含量随演替呈减少的趋势, 但根系中全N、全P的含量都以马尾松林为最多, 混交林和季风林含量彼此相当。3)各土层中N:P随演替的进行呈现明显增加趋势, 马尾松林、混交林和季风林0-10 cm土层中N:P分别为2.3、2.5和3.6; 植物各器官中N:P随演替的进行也呈增加趋势, 且叶片和根系中的N:P相近, 马尾松林、混交林和季风林叶片中N:P分别为22.7、25.3和29.6。基于上述结果, 探讨了南亚热带森林生态系统植物与土壤中N:P特征、森林演替过程中植物与土壤中N:P变化规律以及P对南亚热带森林生态系统的限制作用。结果表明, P已经成为南亚热带森林生态系统生物生长和重要生态过程的限制因子。     

喜旱莲子草入侵群落土壤对植物生长的影响

分别以受喜旱莲子草(Alternanthera philoxeroides)入侵和未受喜旱莲子草入侵的当地植物群落土壤为生长基质,比较不同基质上入侵植物喜旱莲子草和同属的土著植物莲子草(A.sessilis)的生长指标,探讨喜旱莲子草入侵群落土壤对喜旱莲子草及莲子草生长的影响机制。结果表明,喜旱莲子草入侵群落土壤抑制了莲子草的生长,显著降低了根生物量、茎生物量和总生物;改变了形态特征,显著降低了分枝数量、茎长度、根长、根体积;减少了对根的生物量分配,显著抑制了根质量比与根冠比。喜旱莲子草入侵群落土壤对入侵植物喜旱莲子草的生物量、分枝数量、茎长度、根长、根体积没有显著的抑制作用,而显著增加了其叶片数量和叶质量比。这种效应将有利于喜旱莲子草在入侵地形成单优群落,表明土壤在喜旱莲子草成功入侵中起了重要作用。     

Estimating plant responses to climate by direct gradient analysis and geographic distribution analysis

We characterised the climatic behaviour of 53 woody species in terms of the climatic factors that play the main role in controlling species distribution in the study area. Floristic and climatic data were obtained from 150 stands in sites under climatic control (i.e. eu-climatopes). The sampling strategy used allowed a reliable match between floristic and climatic observations. Different methods of frequency analysis and goodness-of-fit tests were used to identify associations between species occurrence and climatic characteristics. The species' responses were summarised by statistics describing ecological preferences and amplitudes, and species were grouped accordingly. A Gaussian response model was fitted to the abundance data along the main climatic gradients for selected species and response surfaces were derived by spatial analysis for a set of indicator species. Frequency analysis methods detected 42 indicator taxa for the Baudiere's Qe drought index, and lower numbers, 34 and 22, respectively, for the mean minimum coldest-month temperature and the daily temperature range in the coldest month. Goodness-of-fit tests revealed a lower number of ecological profiles with statistically significant deviations from equidistribution. We discuss the relative performance of the different methods and suggest that the combined use of statistical tests and frequency analyses may improve estimation of the environmental requirements of species. We also recommend using the species' responses to key environmental factors as reliable criteria in the definition of plant functional types. This revised version was published online in August 2006 with corrections to the Cover Date.     

模拟氮沉降增加对南亚热带主要森林土壤动物的早期影响

对模拟氮沉降增加条件下3种南亚热地带代表性森林(季风常绿阔叶林、针阔混交林和马尾松纯林)内土壤动物群落的早期响应特征进行了比较研究.试验采用模拟的方法,人为构建了一个氮沉降增加梯度系列,即对照、低氮处理(50kg·hm^-2·yr^-1)、中氮处理(100kg·hm^-2·yr^-1)和高氮处理(150kg·hm^-2·yr^-1).结果表明,不同林分对氮沉降增加的响应不同;季风林与针叶林表现了两种截然相反的变化趋势,前者反映的是负向效应,土壤动物的3项指标均明显下降,而后者则反映出明显的正向效应,使得针叶林土壤动物的各项指标达到混交林,甚至季风林的水平;氮沉降增加对混交林则没有表现出明显的作用.不同氮沉降增加水平所产生的效应也不完全相同.在季风林内,参比对照,中氮处理往往表现出显著的负向效应(P＜0.05),而低氮处理反应不明显;在针叶林内,氮处理的正向效应随着处理的加强而持续上升,尤其是对于土壤动物类群数指标,这种持续性均达到了显著性水平(P＜0.05).可以认为,这些结果反映了森林生态系统对氮饱和的响应机制.     

气候过渡带锐齿栎林土壤呼吸对降雨改变的响应

作为大气与陆地生态系统之间的第二大碳通量,土壤呼吸是评价陆地生态系统碳循环及碳汇能力的不确定性来源之一。降雨格局改变及其导致的土壤水分变化是调节土壤呼吸的重要驱动。气候过渡带的水热状况受全球降雨格局改变的影响更为明显,揭示该区域森林土壤呼吸对降雨改变的响应规律有助于改善碳循环模型的预测精度。然而,气候过渡区的土壤碳排放过程如何响应降雨格局改变尚不清楚。通过在亚热带-暖温带的过渡区(宝天曼)开展降雨改变实验,以阐明锐齿栎林土壤呼吸及其温度敏感性对降雨增加(50%)和减少(50%)的响应规律。结果表明,降雨增加显著提高土壤湿度(+8.92%)而不影响土壤温度。与对照相比,降雨增加导致土壤呼吸显著提高80.5%,其土壤呼吸的温度敏感性(4.07)显著高于对照样地(2.66)。增雨处理下的土壤呼吸与土壤湿度呈负相关。降雨减少则显著降低土壤湿度(-10.25%),并对土壤呼吸有促进趋势,然而,对土壤呼吸的温度敏感性(2.64)无显著影响。减雨处理下的土壤呼吸强度与土壤湿度呈正相关。这意味着在我国亚热带—暖温带过渡区,降雨增加或减少均对土壤呼吸有不同程度的刺激作用,进而很可能减弱该区域森林生态系统土壤的固碳潜力。     

Factors relating to regional and local success of exotic plant species in their new range

Aim To estimate invasiveness of exotic plant species, many studies have used the frequency of occurrence within a defined region. This measure is informative on how widespread exotics are, however, it does not inform on their local dominance, which is crucial for conservation of biodiversity and ecosystem functioning. The aim of the present study is to determine if regional frequency of occurrence of exotic plant species indeed is indicative of their local dominance. We also determined which plant traits and other factors predict regional and local frequencies best. Location The Netherlands. Methods We used information on exotic plant species established in The Netherlands and compared traits relating to their frequency of occurrence regionally (the entire country) and their frequency of dominance locally (in 1–100 m² quadrats). We created minimal adequate models with factors explaining regional frequency and frequency of local dominance of 111 exotic plant species in The Netherlands. Results The model that used plant traits to explain regional frequency of exotic plant species differed from the models that best explained their frequency of local dominance. Regionally, the factors that correlated with frequency were: life form, height, polyploidy, length of flowering season, residence time, human use and origin. The factors that correlated to frequency of local dominance were lateral vegetative spread and residence time. Main conclusions We conclude that plant traits relating to the regional frequency of exotic plant species differ from those that relate to their frequency of local dominance. The implication of our results is that predictive studies on plant invasiveness based on regional frequencies may not be indicative of the local impacts. Since the prediction of local impacts is crucial for conservation and risk assessment, our study emphasized the need for better information on the local abundance of exotic invaders.     

Beyond climate control on species range: The importance of soil data to predict distribution of Amazonian plant species

Aim

To evaluate the relative importance of climatic versus soil data when predicting species distributions for Amazonian plants and to gain understanding of potential range shifts under climate change.

Location

Amazon rain forest.

Methods

We produced species distribution models (SDM) at 5‐km spatial resolution for 42 plant species (trees, palms, lianas, monocot herbs and ferns) using species occurrence data from herbarium records and plot‐based inventories. We modelled species distribution with Bayesian logistic regression using either climate data only, soil data only or climate and soil data together to estimate their relative predictive powers. For areas defined as unsuitable to species occurrence, we mapped the difference between the suitability predictions obtained with climate‐only versus soil‐only models to identify regions where climate and soil might restrict species ranges independently or jointly.

Results

For 40 out of the 42 species, the best models included both climate and soil predictors. The models including only soil predictors performed better than the models including only climate predictors, but we still detected a drought‐sensitive response for most of the species. Edaphic conditions were predicted to restrict species occurrence in the centre, the north‐west and in the north‐east of Amazonia, while the climatic conditions were identified as the restricting factor in the eastern Amazonia, at the border of Roraima and Venezuela and in the Andean foothills.

Main conclusions

Our results revealed that soil data are a more important predictor than climate of plant species range in Amazonia. The strong control of species ranges by edaphic features might reduce species’ abilities to track suitable climate conditions under a drought‐increase scenario. Future challenges are to improve the quality of soil data and couple them with process‐based models to better predict species range dynamics under climate change.     

四种荒漠植物生物量分配对土壤因子 的响应及异速生长分析

该研究以四种荒漠植物:盐地碱蓬(Suaeda salsa)、新疆绢蒿(Seriphidium kaschgaricum)、对节刺(Horaninowia ulicina)、骆驼刺(Alhagi sparsifolia)为对象,采用挖掘法获取完整的植株生物量,测定土壤理化性质,并通过四种荒漠植物生物量、生物量分配比对土壤因子的响应程度以及异速生长模型进行了对比分析。结果表明:(1)四种荒漠植物的生物量、生物量分配比重差异明显;新疆绢蒿具有最大的地上、地下生物量,对节刺的生物量最小;根冠比(R/S)大小排序依次是骆驼刺对节刺、新疆绢蒿盐地碱蓬(P0.05)。(2)利用RDA分析土壤因子对R/S的影响,结果发现土壤因子对新疆绢蒿、盐地碱蓬、骆驼刺、对节刺的R/S解释程度分别是16.3%、24.8%、33.1%、35.4%,其中土壤全氮与对节刺的R/S呈正显著关系(P0.05),土壤水分与盐地碱蓬的R/S呈极显著正相关(P0.01)。(3)四种荒漠植物地上—地下间均具有极显著的相关生长关系(P0.01);新疆绢蒿地上—地下间为等速生长关系(α=1),而对节刺和骆驼刺则均为α=3/4的异速生长关系,盐地碱蓬属于非3/4幂指数的异速生长关系(α1),四种荒漠植物间具有共同的异速生长指数(0.767)。以上结果说明艾比湖优势荒漠植物具有功能趋同性,其空间分配特征对土壤因子的响应存在物种特异性。     

Small-scale plant species distribution in snowbeds and its sensitivity to climate change

Alpine snowbeds are characterized by a long-lasting snow cover and low soil temperature during the growing season. Both these key abiotic factors controlling plant life in snowbeds are sensitive to anthropogenic climate change and will alter the environmental conditions in snowbeds to a considerable extent until the end of this century. In order to name winners and losers of climate change among the plant species inhabiting snowbeds, we analyzed the small-scale species distribution along the snowmelt and soil temperature gradients within alpine snowbeds in the Swiss Alps. The results show that the date of snowmelt and soil temperature were relevant abiotic factors for small-scale vegetation patterns within alpine snowbed communities. Species richness in snowbeds was reduced to about 50% along the environmental gradients towards later snowmelt date or lower daily maximum temperature. Furthermore, the occurrence pattern of the species along the snowmelt gradient allowed the establishment of five species categories with different predictions of their distribution in a warmer world. The dominants increased their relative cover with later snowmelt date and will, therefore, lose abundance due to climate change, but resist complete disappearance from the snowbeds. The indifferents and the transients increased in species number and relative cover with higher temperature and will profit from climate warming. The snowbed specialists will be the most suffering species due to the loss of their habitats as a consequence of earlier snowmelt dates in the future and will be replaced by the avoiders of late-snowmelt sites. These forthcoming profiteers will take advantage from an increasing number of suitable habitats due to an earlier start of the growing season and increased temperature. Therefore, the characteristic snowbed vegetation will change to a vegetation unit dominated by alpine grassland species. The study highlights the vulnerability of the established snowbed vegetation to climate change and requires further studies particularly about the role of biotic interactions in the predicted invasion and replacement process.     

Graph theoretical analysis of the phytosociological structure of plant communities: An application to mixed forest

Summary A sampling method, compatible with the theory elaborated in the previous paper, was used to investigate the mixed-forest community of a woodlot in Southern Ontario. The results provide an illustration of the graph theoretical methods developed for the elucidation of a community's phytosociological structure. Certain conjectures about the community are tested and it is found that Goodall's hypothesis concerning the nature of a plant community is supported. The tests also show that the vegetation of the study area forms a single natural grouping despite the disparity of the position ofAcer saccharum and the polarity evident among the other tree species.Nomenclature follows Gleason (1952).From a thesis submitted to the University of Toronto in partial fulfilment of the requirements for the degree of Master of Science.I wish to thank Dr. G. A. Yarranton for his ideas and helpful supervision, and my father for his advice and encouragement. Thanks ag also due to Miss J. E. Ellard and Mr. S. Roy who helped prepare the figures. This research has been supported by a National Research Council of Canada and by NRCC grant A-2910.     

Ecological consequences through responses of plant and soil communities to changing winter climate

Community processes are now undergoing substantial reconfiguration because of climate change. Although the effects of climate change on ecosystems are currently a major concern, the issues tightly associated with winter climate change have been underrepresented. Given the importance of winter climate variables and events for determining the spatial distribution of communities and their phenological and physiological responses, and the functional roles of each species, all of which are expected to substantially influence community dis/re-assemble in the future, this review focuses on the ecological responses and consequences of terrestrial communities to changing winter climate. In particular, the effects on processes supported by biological interactions are largely undetermined. In this context, focusing on plant–soil feedback as a major interactive multi-system is worthwhile; these interactions can be disentangled through careful evaluation of the functional roles of organisms involved in the feedback (i.e., plants and soil organisms). The underlying mechanisms are indeed complex because direct (i.e., changes in physical conditions) and indirect pathways (i.e., plant-mediated influences on soil-organisms and vice versa) from winter climate change influence the functionality of future ecosystems. To face these issues, the framework of response–effect-traits deserves research priority since this can define community re-organization as the accumulated responses of individual species, which determines the stability and performance of ecosystem functioning. Thus, research that quantifies functional responses and roles of organisms under a changing climate will continue to be essential for the issues of winter climate change, which may become more serious and significant in the near future.