Review on Factors Affecting Plant Competition

The competition refers to the interactions of two or more individuals which compete for resources,and is a key process of plant populations and communities.A comprehensive understanding of plant competition is necessary to predict the responses of ecological systems to environmental changes.The inside factors affecting competition include plant density,biological factors and the biomass.The environmental factors related to competition include light,soil moisture,soil nutrient and altitude.High density affects plant competition by controlling plant growth.Allelochemicals produced by plants directly affect their neighbors. Trees and grasses may compete for resources where their root systems overlap.Herbivorous animals chose to eat some plants,resulting in reduction of competition ability of the plants.Plants make morphological shifts and alter the competitive ability between above-ground and below-ground parts in response to the environmental changes.When shade- tolerant species are absent in mixed forest,less shade tolerant species could maintain their dominance for a long period.In contrast,mixed forest with tolerant species would reduce the dominance of less-tolerant species,maintain and probably increase the dominance through the decline of less-tolerant species.Smaller plants should have longer survival time due to their smaller total water requirements when water is scarce,and the longer survival of plants with higher root allocation could be due to a relative reduction in transpiring surface per unit root length.In nutrient-deficient soils,plants are stressed directly by the lack of adequate nutrients and competitive interactions may be controlled by a plant’s ability to efficiently take up available nutrients.In nutrient-sufficient soils,plants with the highest maximum growth rates may well be the superior competitors.Intensity of light competition declines with altitude.The future research about competition will focus on large scale,long term and multi-population research,the multi-disciplinary cooperat     

甘肃头二三滩自然保护区维管植物多样性调查

采用线路调查和样线调查结合法对甘肃头二三滩自然保护区的维管植物进行了综合调查研究,结果表明:本区分布有维管植物1 314种,隶属138科590属,其中蕨类植物56种,隶属15科29属,种子植物1 258种,隶属123科561属;国家保护植物14种;从属的分布来看,温带性属是保护区植物区系的主要成分;植被类型可划分为4个植被型组,11个植被型,16个植被亚型和28个群系。     

利用植物净化汽车排放污染物的探索研究

针对目前汽车尾气对环境污染日益严重的现象,引出了利用植物对尾气污染物进行净化的方法.然后对国内外对植物与大气污染关系研究的发展动态及研究方法进行了综述和评价.最后参考所述研究方法,提出了利用密闭室法研究植物净化汽车排放污染物的新方法.     

Spatial and environmental effects on plant communities in the Yellow River Delta, Eastern China

Types and structure of plant communities in the Yellow River Delta were investigated by using detrended canonical correspondence analyses (DCCAs) and a two-way indicator species analysis (TWINSPAN). The distribution pattern and influential factors of the plant communities were also analyzed by testing elevation, slope, soil characteristics, longitude and latitude of 134 vegetation samples collected by representative plot sampling methods. Results showed that all the 134 vegetation samples could be divided into seven vegetation groups, separately dominated by Robinia pseucdoacacia, Imperata cylindrical, Miscanthus saccharifleus, Suaeda salsa, Aeluropus sinensis, Phragmites australis and Tamarix chinensis. The vegetation distribution pattern was mainly related to elevation, ground water depth and soil characteristics such as salinity and soluble potassium. Among the factors affecting distribution pattern of the plant communities, the species matrix explained by non-spatial environmental variation accounts for 45.2% of total variation. Spatial variation and spatial-structured environmental variation explain 11.8%, and 2.2%, respectively. Remained 40.8% of undetermined variation is attributed to biological and stochastic factors.     

燕山地区环保型和保健型植物配置初探

在分析燕山地区环境现状和污染物排放现状的基础上,选择了对大气、水、土壤污染物吸附能力强和降低噪声能力强的环保型植物和对不同人群有保健作用的保健型植物,提出了适合燕山地区的6种不同土地利用类型的环保型植物配置方式,同时也兼顾了保健型植物的配置。     

Relationships between <Emphasis Type="Italic">Artemisia ordosica</Emphasis> communities and environmental factors following sand-dune stabilization in the Mu Us desert,northwest China

Artemisia ordosica is an excellent sand-fixing shrub for sand stabilization in northwestern China. Sand dune stabilization, a critically important process, leads changes in abiotic factors, such as soil structure and nutrient contents. However, the effects of factors on an A. ordosica community following sand stabilization remain unclear. In this study, we used canonical correspondence analysis (CCA) to examine the relationships between A. ordosica communities and environmental factors at three habitats: semi-fixed dune (SF), fixed dune with low-coverage biological soil crust (F), and fixed dune with high-coverage biological soil crust (FC) in Mu Us desert. The mean height and coverage of plants increased with sand stabilization, while species diversity and richness increased initially and then reduced significantly. Correlation analysis and CCA revealed that slope, soil organic carbon, and nutrient contents, proportion of fine soil particles, soil moisture, and thickness of biological soil crust were all highly correlated with vegetation characteristics. These environmental factors could explain 40.42 % of the vegetation–environment relationships at the three habitats. The distribution of plant species was positively related to soil moisture in the SF dune. Soil moisture, soil nutrient, and fine-particle contents mainly affected plants distribution in the F dune. In the FC dune, distribution of plant species was positively and negatively correlated with the thickness of biological soil crust and soil moisture at a depth 0–20 cm, respectively. The dominance value of typical steppe species increased significantly following sand-dune stabilization and relations between species and samples in CCA ordination bi-plots showed that perennial grasses could invade the A. ordosica community on FC, indicating A. ordosica communities had a tendency to change into typical steppe vegetation with the further fixation. We conclude that the significant differentiation not only occurred in community characteristics, but also in the relationships between vegetation and environmental factors among the three stages of dune fixation. So, restoration of degraded dune ecosystems should be based on habitat conditions and ecological needs.     

模拟常熟地区自然群落的植物景观设计

近年来,随着乡土景观营造运动的兴起,模拟自然植物群落的植物景观设计也逐渐引起人们的重视(Clark et al.,1998;Kielbaso,2008).通过研究分析某地区自然群落的基本类型、层次结构,从而有目的借鉴该地区自然群落的景观,在提高园林植物配置的科学性及艺术性、体现当地植物景观特色等方面具有重要的意义(苏雪痕,1983).     

桑植石漠化林地植物多样性及群落数量特征分析

以湖南桑植县石漠化区为研究对象,采用样方调查法对3个不同石漠化等级样地进行植被调查,分析不同石漠化等级植物物种组成结构及植物多样性指数差异,并根据Jaccard群落相似性原理进行不同石漠化等级植物群落间的相似度评价分析.结果表明:调查区共出现草本植物23科39种、木本植物26科38种,优势科为菊科、蔷薇科、百合科、禾本...     

地带性木本植物群落功能型的水热分布格局

植物功能型是对环境条件做出相似的反应和对关键生态学过程具有相似影响的植物组合。不同功能型植物对生态系统过程的作用不同 ,通过植物功能型的分析对揭示生态系统功能至关重要。甘肃省境内 5种地带性木本植物群落 (亚热带常绿落叶阔叶林、暖温带落叶阔叶林、温带针阔混交林、寒温性针叶林和荒漠旱生灌木群落 )依据植物体的高度、叶片的生长对策及果实类型可划分出 2 3种功能型。其分布格局与水热因子的相关分析表明 :1)湿热的生境利于乔木、大灌木、藤木、寄生植物和常绿植物及翅果、坚果、核果、果、颖果类植物的发育 ,干冷生境利于灌木、小灌木和落叶植物以及蒴果类植物的发育。 2 )干果类和肉果类的成因可能与植物生长环境中水分供应状况密切相关 ,即潮湿的生境利于肉果类植物的发育 ,干旱的生境有利于干果类 (如胞果 )的发育。 3)研究区域地带性木本植物群落物种丰富度和功能型的丰富度格局主要受制于水分梯度影响 ,而良好的水热组合可孕育木本植物群落最丰富的果实类型。     

云南高原4种湿地植物群落对生活污水TP、COD净化效果研究

在野外调查的基础上,选取小黑三棱+杉叶藻+荇菜、水葱+睡菜+荇菜、菰+荸荠+荇菜和香蒲+睡菜+眼子菜等4种云南高原常见湖滨湿地植物群落作为试验材料在净化槽中进行水质净化模拟研究。结果表明,4种湿地植物群落对生活污水TP(总磷)和COD(化学需氧量)都有较好的净化效果,各植物群落对TP和COD的去除率均显著高于无植物对照组(P<0.05);但不同群落之间净化效果存在较大的差异性,水葱+睡菜+荇菜群落对TP去除效果显著优于其他3种群落(P<0.05),去除率达到94.72%,与该群落挺水植物水葱的生长特性密切相关;植物群落能有效促进湿地对污染物的去除效果,各群落对TP和COD去除的贡献率分别为32.73%～49.63%和14.76%～20.46%;湿地运行过程中,COD的去除效果存在不稳性和波动性。在湖滨带的恢复与重建过程中,适当增加挺水植物的比例,能有效促进湿地对TP和COD的净化效果。     

Plant hormesis and Shelford's tolerance law curve

Shelford's law of tolerance is illustrated by a bell-shaped curve depicting the relationship between environmental factor/factors' intensity and its favorability for species or populations.It is a fundamental basis of ecology when considering the regularities of environment impacts on living systems,and applies in plant biology,agriculture and forestry to manage resistance to environmental limiting factors and to enhance productivity.In recent years,the concept of hormesis has been increasingly used to study the dose-response relationships in living organisms of different complexities,including plants.This requires the need for an analysis of the relationships between the hormetic dose-response model and the classical understanding of plant reactions to environments in terms of Shelford's law of tolerance.This paper analyses various dimensions of the relationships between the hormetic model and Shelford's tolerance law curve under the influence of natural environmental factors on plants,which are limiting for plants both in deficiency and excess.The analysis has shown that Shelford's curve and hormetic model do not contradict but instead complement each other.The hormetic response of plants is localized in the stress zone of the Shelford's curve when adaptive mechanisms are disabled within the ecological optimum.At the same time,in a species range,the ecological optimum is the most favorable combination of all or at least the most important environmental factors,each of which usually deviates slightly from its optimal value.Adaptive mechanisms cannot be completely disabled in the optimum,and hormesis covers optimum and stress zones.Hormesis can modify the plant tolerance range to environmental factors by preconditioning and makes limits of plant tolerance to environmental factors flexible to a certain extent.In turn,as a result of tolerance range evolution,quantitative characteristics of hormesis(width and magnitude of hormetic zone) as well as the range of stimulating doses,may significantly differ in various plant species and even populations and intra-population groups,including plants at different development stages.Using hormetic preconditioning for managing plant resistance to environmental limiting factors provides an important perspective for increasing the productivity of woody plants in forestry.     

植物杂种优势及基因组多倍化机制研究概述

在植物进化及物种形成过程中,通过2个亲本的杂交可以使后代表现出速生、高产、高抗逆等优于亲本的性状,形成杂种优势;而通过同源或异源基因组加倍,也可使植物表现出明显优于亲本的生长发育性状或环境适应力,形成多倍体优势。因此,杂交及基因组多倍化被认为是推动植物进化和物种形成的2个主要驱动力。杂种优势及基因组多倍体优势已在农业生产实践中得到广泛应用,并产生巨大价值。基于此,探究植物杂交优势、基因组多倍体优势具有重大理论意义和应用价值,历来受到研究者的高度关注。目前,这方面的研究特别是有关杂种优势及基因组多倍化分子机制方面的研究已取得若干重大进展,本文旨在对这些研究成果进行概述,并对今后在木本植物中开展相关研究进行展望。     

玉溪市国家重点保护野生植物调查研究

1999和2002年采用典型样方法、核实法和访问估计法，对玉溪市境内的国家重点保护野生植物进行了调查。调查结果表明：玉溪市有分布记录的国家重点保护野生植物19种；基本查清了这些物种所处的植被类型、分布状况、分布面积以及濒危状态。调查报告逐种记述了这19种植物各项调查内容的结果，并针对这些物种的濒危状态，提出了保护性措施。     

昆明市盘龙江滨水绿地植物群落的特征分析

以盘龙江滨水植物为研究对象,采取实地调查、数据收集和数据处理的研究方法,对48个样方及74个典型群落进行了深入调查.分析并总结了盘龙江滨水植物群落的特征,提出了滨水绿地植物发展的建议以供滨水绿地的景观设计与营造参考.     

汕头市中山公园植物种类调查及配置分析

通过对中山公园实地调研,对园林植物种类、生活型、生态型和观赏特性进行了分析与总结,结果表明:中山公园植物总共162种,隶属于69科129属;具有亚热带地域风味以及岭南风情,植物群落布设自然合理,既符合适地适树的科学原则,也具有外来树种与乡土树种相结合等特点;存在有乡土树种种类少,人类活动与行为对植物景观造成的影响较大,公园的养护管理不到位以及特色植物菊花的配置形式简单等问题;因此在探讨植物种类选取的科学性基础上,从科学性、艺术性、生态性等角度出发,提供了一些优化建议。     

构建武汉节约型城市园林植物景观

指出了节约型植物景观作为一种可持续的园林景观，是实现节约型园林绿化的重要途径之一。分析了目前武汉地区植物景观建设中存在的问题，并从植物种类的选择、植物群落的构建等方面探讨了武汉地区使用植物景观设计方法构建节约型园林的重要途径。     

植物盐胁迫适应机制研究进展

综述植物对盐胁迫的适应机制,包括提高抗氧化酶系统的活性、调节激素含量、离子区域化、离子选择性吸收、拒盐作用及合成渗透调节物质.目前植物盐胁迫适应机制的研究取得了一定进展,但在分子水平上仍有待于进一步深入.以现有研究为基础,利用分子生物学研究技术、基因工程技术和突变体筛选是根本解决植物抗盐性问题的重要途径和方法.     

乡土植物在园林中对生物多样性保护的作用

城市的发展导致了大面积土地利用方式的改变,引起的直接后果是生物多样性的丧失。解决这一矛盾的方法之一是在园林绿化中较多地应用乡土植物。乡土植物作为大自然长期进化的结果,能为当地物种的保护提供更多的栖息地和食物资源,对生物多样性保护具有重要意义。文章从园林绿化发展的背景出发,提出应用乡土植物的必然性,并介绍了它在提高植物与动物多样性方面的贡献。同时以广州园林绿化作为案例诠释理论,并提出在保护生物多样性方面应做的工作,以及在园林绿化中乡土植物的配置。     

校园不同功能区植物群落结构与环境舒适度关系分析

选择云南农业大学校园教学科研区和生活休憩区景观绿地中具有代表性的植物群落，以二氧化碳浓度、噪音及温度为环境舒适度评价指标，采用天然群落样方调查法和问卷调查法，分析了植物群落结构与环境舒适度之间的关系，以期为构建合理舒适的人工植物群落提供量化研究参考。结果显示：以单层植物群落结构作为对照组，教学科研区多层植物群落对环境舒适度的改善效果最好：其多样性指数H为1．471、二氧化碳浓度下降5％、噪音下降10％、温度下降15％、环境满意度62％；生活休憩区中双层植物群落对环境舒适度的改善效果最好：其多样性指数H为0．864、二氧化碳浓度下降2％、噪音下降3％、温度下降10％、环境满意度为76％。其中，教学科研区与生活休憩区植物群落结构由单层向双层递进和由双层向多层递进时，表现出环境舒适度与之呈正相关；而生活休憩区植物群落结构在由双层向多层递进时，则没有表现出与环境舒适度之间的正相关性。     

三种园林植物叶形态生理指标及其环境指示作用

通过测定3种南方园林植物的叶面积、叶片含水量、比叶面积和叶绿素指数4项形态和生理指标,并对两种不同环境条件下各指标的差异进行分析,验证3种园林植物利用资源及对环境适应的能力。结果表明,高山榕(Ficus altissima)生长较快但不能较好地适应大气污染,白千层(Melaleuca quinquenervia)能抗大气污染,而尖叶杜英(Elaeocarpus apiculatus)更能适应资源丰富的环境条件。