A geometric algorithm for an artificial life form based on anachronistic methods

Modern methods of spawning new technological motifs are not appropriate when it is desired to realize artificial life as an actual real world entity unto itself (Pattee 1995; Brooks 2006; Chalmers 1995). Many fundamental aspects of such a machine are absent in common methods, which generally lack methodologies of construction. In this paper we mix classical and modern studies in order to attempt to realize an artificial life form from first principles. A model of an algorithm is introduced, its methodology of construction is presented, and the fundamental source from which it sprang is discussed.

The importance of plant life form on spatial associations along a subtropical coastal dune gradient

Questions Does the spatial association between isolated adult trees and understorey plants change along a gradient of sand dunes? Does this association depend on the life form of the understorey plant? Location Coastal sand dunes, southeast Brazil. Methods We recorded the occurrence of understorey plant species in 100 paired 0.25 m2 plots under adult trees and in adjacent treeless sites along an environmental gradient from beach to inland. Occurrence probabilities were modelled as a function of the fixed variables of the presence of a neighbour, distance from the seashore and life form, and a random variable, the block (i.e. the pair of plots). Generalized linear mixed models (GLMM) were fitted in a backward step-wise procedure using Akaike's information criterion (AIC) for model selection. Results The occurrence of understorey plants was affected by the presence of an adult tree neighbour, but the effect varied with the life form of the understorey species. Positive spatial association was found between isolated adult neighbour and young trees, whereas a negative association was found for shrubs. Moreover, a neutral association was found for lianas, whereas for herbs the effect of the presence of an adult neighbour ranged from neutral to negative, depended on the subgroup considered. The strength of the negative association with forbs increased with distance from the seashore. However, for the other life forms, the associational pattern with adult trees did not change along the gradient. Conclusions For most of the understorey life forms there is no evidence that the spatial association between isolated adult trees and understorey plants changes with the distance from the seashore, as predicted by the stress gradient hypothesis, a common hypothesis in the literature about facilitation in plant communities. Furthermore, the positive spatial association between isolated adult trees and young trees identified along the entire gradient studied indicates a positive feedback that explains the transition from open vegetation to forest in subtropical coastal dune environments.

Managed livestock grazing is compatible with the maintenance of plant diversity in semidesert grasslands

Even when no baseline data are available, the impacts of 150 years of livestock grazing on natural grasslands can be assessed using a combined approach of grazing manipulation and regional-scale assessment of the flora. Here, we demonstrate the efficacy of this method across 18 sites in the semidesert Mitchell grasslands of northeastern Australia. Fifteen-year-old exclosures (ungrazed and macropod grazed) revealed that the dominant perennial grasses in the genus Astrebla do not respond negatively to grazing disturbance typical of commercial pastoralism. Neutral, positive, intermediate, and negative responses to grazing disturbance were recorded amongst plant species with no single life-form group associated with any response type. Only one exotic species, Cenchrus ciliaris, was recorded at low frequency. The strongest negative response was from a native annual grass, Chionachne hubbardiana, an example of a species that is highly sensitive to grazing disturbance. Herbarium records revealed only scant evidence that species with a negative response to grazing have declined through the period of commercial pastoralism. A regional analysis identified 14 from a total of 433 plant species in the regional flora that may be rare and potentially threatened by grazing disturbance. However, a targeted survey precluded grazing as a cause of decline for seven of these based on low palatability and positive responses to grazing and other disturbance. Our findings suggest that livestock grazing of semidesert grasslands with a short evolutionary history of ungulate grazing has altered plant composition, but has not caused declines in the dominant perennial grasses or in species richness as predicted by the preceding literature. The biggest impact of commercial pastoralism is the spread of woody leguminous trees that can transform grassland to thorny shrubland. The conservation of plant biodiversity is largely compatible with commercial pastoralism provided these woody weeds are controlled, but reserves strategically positioned within water remote areas are necessary to protect grazing-sensitive species. This study demonstrates that a combination of experimental studies and regional surveys can be used to understand anthropogenic impacts on natural ecosystems where reference habitat is not available.

Diversidade e padrões estruturais da vegetação halófila-psamófila das restingas do Rio de Janeiro

As restingas do Estado do Rio de Janeiro são áreas de sedimentação predominantemente quaternária, descontínuas geograficamente, formadas em função das mudanças paleoclimáticas, flutuações do nível do mar e transporte longitudinal de sedimentos. A diversidade e a estrutura da vegetação halófila-psamófila presente nestas restingas são os principais focos deste estudo, onde foram analisadas a similaridade florística, as formas de vida e síndrome de dispersão, o padrão de riqueza e diversidade, a distribuição das espécies e os parâmetros de cobertura vegetal, serrapilheira, solo desnudo e salinidade da água do mar. Foram amostradas nove áreas de restinga, a saber, Praia do Sul, Marambaia, Grumari, Marapendi, Maricá, Massambaba, Barra de São João, Jurubatiba e São João da Barra. Foram encontradas 90 espécies, distribuídas em 33 famílias, 69 gêneros, sendo as famílias de maior riqueza específica: Asteraceae (10), Poaceae (9 espécies), Fabaceae (9) e Rubiaceae (6). Foi registrada uma baixa riqueza de espécies nas áreas avaliadas, variando de 25 a 48. Somente 11 espécies ocorreram em todas as áreas (Alternanthera maritima, Blutaparon portulacoides, Canavalia rosea, Cereus fernambucensis, Euphorbia hyssopifolia, Ipomoea imperati, Ipomoea pes-caprae, Panicum racemosum, Remirea maritima, Sporobolus virginicus, Stenotaphrum secundatum), e 12 são dominantes, em uma ou mais áreas (Allagoptera arenaria, Alternanthera maritima, Blutaparon portulacoides, Canavalia rosea, Ipomoea imperati, Ipomoea pes-caprae, Mollugo verticillata, Panicum racemosum, Remirea maritima, Spermacoce capitata, Sporobolus virginicus, Stenotaphrum secundatum), existindo um grande número de espécies raras. O índice de diversidade de Shannon variou de 1,49 a 2,40, e a equabilidade de Pielou de 0,82 a 0,60. O agrupamento formou dois grandes grupos, sendo o primeiro constituído por Barra de São João, Praia do Sul, Marambaia, Grumari e Marapendi, e o segundo por Jurubatiba, São João da Barra, Maricá e Massambaba. As áreas mais similares floristicamente foram Maricá e Massambaba (58%), Grumari e Marapendi (56%), e Barra de São João e Praia do Sul (50%). A vegetação apresenta uma flora característica, com diferença na composição entre as áreas, e similaridade entre áreas geograficamente mais próximas. Um terço das espécies identificadas são caméfitos (34,56%), seguida por fanerófitos (20,98%), geófitos (16,04%), hemicriptófitos (12,34%), terófitos (13,58%) e duas lianas. Na dispersão predomina a autocoria (41,97%), anemocoria (33,33%) e zoocoria (24,69%). O tamanho das áreas perpendicularmente ao mar não está relacionado com aumento da riqueza, nem apresenta o padrão de aumento com o distanciamento do mar. Existem diferenças da riqueza e da diversidade entre as áreas, não havendo uma homogeneidade ao longo do litoral. Há uma zonação, com espécies distribuídas próximas ao mar (Allagoptera arenaria, Alternanthera maritima, Blutaparon portulacoides, Canavalia rosea, Cassytha filiformis, Cereus fernambucensis, Hydrocotyle bonariensis, Ipomoea pes-caprae, Schinus terebinthifolia, Sophora tomentosa, Stenotaphrum secundatum, Cyrtocymura scorpioides), e ao longo do gradiente perpendicular ao mar (Chamaecrista flexuosa, Euphorbia hyssopifolia, Ipomoea imperati, Mollugo verticillata, Panicum racemosum, Paspalum maritimum, Remirea maritima, Sporobolus virginicus). O modelo de série logarítmica é o que melhor representa a vegetação, independente da diversidade ou riqueza. A cobertura vegetal variou entre as áreas. A serrapilheira e o solo desnudo estão estreitamente relacionados com a cobertura vegetal, havendo variação entre as áreas.

东北地区蒙古栎林的群落学特征及物种多样性

根据野外样地调查方法取得数据，我对样地资料进行了以下几方面的分析。根据吴征镒、王荷生区系分析方法，分析了东北地区蒙古栎群落中261种维管植物的区系成分，还分别分析了蒙古栎群落的乔木层、灌木层、草本层以及层间植物的区系成分。比较了东北地区的10个地点和河北省1个地点的蒙古栎群落物种所在属的分布区类型，计算了温带属与热带属（T／R）的比值，并给出了T／R值、纬度和海拔三者关系的回归方程。最后对这种分布格局产生的原因进行了解释。分析了东北地区10个地点蒙古栎群落中290个维管植物的生活型，发现东北地区蒙古栎群落物种的生活型以地面芽最多，同时本文对地下芽、地面芽与纬度、海拔的关系进行了回归分析。根据Raunkiaer系统，分析了蒙古栎群落中337种维管植物的叶型，发现蒙古栎群落植物以小型叶为主，并分析了叶的边缘状况，全缘叶占22.3％。还分别分析了群落乔木、灌木和草本的叶型及叶缘状况。分析了13个地点蒙古栎群落物种相似性与两地之间距离的关系。 比较了丰林自然保护区三个不同年龄林（64年、100年和270年）物种多样性特征。对黑龙江省七个地点的蒙古栎林的更新特点的分析，蒙古栎林可划分为不同特点的蒙古栎林型，即蒙古栎纯林、蒙古栎桦林林、蒙古栎落叶松林、蒙古栎槭树林、蒙古栎红松林和蒙古栎红松混交林等。 比较了13个地点蒙古栎群落的物种丰富度、Simpson指数、PIE指数、Shannon指数和Pielou指数。并对蒙古栎群落和核桃揪群落、蒙古栎群落和长白落叶松群落、蒙古栎群落和杂灌丛群落及其交错带进行了研究。采用点样地法对五个地点蒙古栎的邻体多样性进行了研究，用物种共同出现百分率测定了4个地点的蒙古栎与其伴生种的种间联结值（PC值），并引入了LS值方法（即相邻物种的平均个体数目），对4个地点蒙古栎群落在不同的环境因子下物种多样性的进行了比较。

中国暖温带森林群落多样性若干问题的研究

中国暖温带落叶阔叶林区维管植物共158科，931属，近4000种（含亚种，变种和变型），种子植物l3l科，877属，3770余种。暖温带植物区系有很强的温带性质，各类温带成分共548属，而各类热带成分仅226属，热带成分与温带成分(R/T)的比率为0．31。运用TWINSPAN和DCA对全国34个植物区系进行了数量分类排序，结果反映了一个地区的植物区系性质主要取决于其所在地的地理位置，同时也受山地海拔高度的强烈影响这一植物区系的基本特征。 根据暖温带森林植物的特点，修订了Raunkiear生活型系统。暖温带森林植物以地面芽植物(H)占较大的优势，占暖温带全部种类的33.9%;其次是地下芽(G)植物，占l 9.7%;全部高位芽植物占27.5%，绝大部分为落叶阔叶高位芽植物。主要由这些生活型组成的暖温带植物生活型总谱基本反映了暖温带夏季温暖多雨、冬季寒冷干旱的中纬度地区地面芽植物群落气候特征。 暖温带森林植被类型主要有7个植被亚型，约50个群系。辽东栎群落是典型的地带性森林群落。应用TWINSPAN和DCA程序将68块暖温带部分地区辽东栎群落样地和83块北京山区辽东栎群落样地分别划分为1 5个和14个群落类型。用物种丰富度指数、Simpson指数、多样性奇测法、Shannon-Wiene r指数、Pielou均匀度指数，Heip均匀度指数、AIatalo均匀度指数等常用的多样性测度方法，分别对暖温带和北京山区辽东栎群落的多样性进行了测度，结果发现，多样性作为一个整体与DCA第1轴有很大的相关关系：暖温带辽东栎群落多样性指数与DCA第1轴的复相关系数为0.7左右，北京山区较高，为0.8左右。多样性的空间特征为：随海拔的升高和纬度的降低，多样性指数呈上升趋势，反映了水热条件在辽东栎水平分布范围内、人类活动和水分因子在辽东栎垂直分布范围内对群落多样性的影响;不同群落之间多样性指数由低到高的顺序为：灌丛、辽东栎萌生丛、辽东栎林、辽东栎纯林、混交林，符合群落演替过程中多样性的动态规律。 对秦岭主峰太白山海拔1400-1600m之间植被类型和物种多样性进行了研究，在划分的1 5种群落类型中，以位于海拔1500-2300m之间的落叶阅叶混交林和栎类混交林的群落多样性最高，在海拔2300-3600m之间，群落多样性趋于单调下降，反映了热量的不足在这一海拔高度范围成为多样性的主要限制因子。

北京东灵山地区森林植物养分利用效率研究

本文选择东灵山地区具有代表性的11种植物，研究了植物叶片养分元素动态特征以及各个层次物种、生活型和生境等对植物叶片养分元素再吸收的影响。主要结论如下： 1、不同物种间、以及相同物种在不同森林类型内的叶片C素含量变化程度较小;11个物种之间叶片N素养分浓度差很大，但各种植物叶片的N素含量的季节变化比较一致，大多数情况下表现为单峰型或双峰变化曲线;各种森林类型中11种植物叶片P的最高含量都出现在生长初期，以后开始下降。 2、在物种水平、养分再吸收是一种重要的养分保存机制，N素和P素再吸收率大约为50%，对这两种养分元素而言，相同生境下生长的不同植物种的养分再吸收率不同，存在显著差异，而同一植物种不同生境下养分再吸收率之间也存在差异，而S素的差异则不显著。 3、同一生活型在不同的森林类型中养分再吸收率差异不明显，同一森林类型中不同生活型的养分再吸收率差异也不明显;高养分再吸收率不是低养分环境所选择的优势性状，低养分环境中的物种主要通过延长叶片寿命和加强低养分浓度状况下的物质合成来适应低养分环境。 4、除了土壤pH值外，土壤容重、土壤有机质、土壤全氮、土壤阳离子交换量在三种生境下都表现出一定的差异性。华北落叶松林生境下的土壤养分含量较丰富，其次是落叶阔叶混交林，辽东栎林相对前二种生境其土壤养分相对低一些，但在三种生境之间养分元素再吸收率差异不显著，植物养分再吸收没有或微弱地受控于土壤养分获得的能力。

子午岭辽东栎天然林土壤种子库研究

结合野外调查与室内试验对子午岭辽东栎天然林的种群生长状况,枯落层种子库,不同坡位土壤种子库物种组成、数量特征、生活型及其与地上植被的相似性进行了较为系统的研究。结果表明:(1)试验萌发鉴定出的幼苗共有24种,隶属于16科,其中多年生草本和落叶灌木物种比例最高,分别占种子库物种总数的58.33%和12.5%;(2)整个子午岭天然辽东栎林土壤种子库总密度为12 761.44粒/m2,种子主要分布在枯枝落叶层和0-2.5 cm土层中,其中,辽东栎种子密度为752.5粒/m2,占整个样地土壤种子库总密度的5.89%,表明辽东栎种子萌发能力很差,该林分群落天然更新缓慢。(3)子午岭天然辽东栎林的下坡位物种多样性指数较其它坡位高,但各个样地物种多样性指数均高于对照;(4)天然辽东栎纯林的种群生长状况良好,树龄均为成年树种;(5)方差分析表明:辽东栎的胸径、地径在不同坡位之间均具有显著性差异(P>0.05);(6)相关分析表明:枯枝落叶层厚度,重量与土壤种子库密度之间具无显著相关性(P<0.05)。

四川九顶山西坡及龙肘山维管植物区系和植物多样性研究

横断山地区是一个十分自然的植物区系地区，在中国植物区系分区中是作为泛北极植物区中国-喜马拉雅亚区中的一个地区，其种子植物区系具有丰富的科、属、种，地理成分复杂，特有现象和替代现象明显。该地区作为植物区系和生物多样性的研究热点地区，长期以来极受中外植物学家关注。横断山脉东缘是中国-喜马拉雅和中国-日本植物区系的交汇过渡区域，北部的岷江流域以及南部的金沙江流域，孕育了该区丰富的物种资源和植被资源。而岷江干热河谷和金沙江干热河谷的相似性和相关性，更为该区的植物区系和生物多样性南北的对比研究提供了有利的条件。 本研究选择的九顶山西坡和龙肘山分别位于横断山区北部和南部，九顶山属岷江流域而龙肘山属金沙江流域。本研究结合植物区系研究和生物多样性研究，对该区的植物资源进行调查。通过样带调查和样线踏查结合，大量详实的野外样方调查和标本采集，进行传统的区系研究和生物多样性研究。研究该区物种多样性的海拔梯度格局及其潜在的影响影子，并利用新的区系评估质量方法对九顶山西坡的植物区系质量进行定量的研究，以期能更为深刻的理解该区的植物资源，为该区的资源保护和利用提供合理可行的建议。主要研究结论如下： 1）九顶山西坡植物区系的性质和特点 经鉴定和统计，九顶山西坡共有1707 种维管植物，分属617 属和140 科,其中种子植物1616 种，分属572 属117 科。就科的分布区成分构成而言，该区系的热带成分与温带成分相当，热带成分略占优势，表明九顶山西坡的植物区系与热带植物区系有较强的联系。但是，在九顶山西坡属的分布区类型所占的比例上，温带成分远远超过了热带成分，本区的种子植物分布表现出明显的温带性质。且温带分布类型的许多物种组成了九顶山西坡植被的建群种和优势种，是本区系最重要的成分，充分体现了本区系的温带性质。 2）九顶山西坡不同植被带的生物多样性海拔梯度格局 基于对土门-断头崖、茶山-九顶山、雁门沟-光光山三条垂直植被样带的调查，我们发现九顶山西坡的生物多样性沿海拔梯度的变化呈现出一定的规律性，不同样带之间有一定差异。就三条样带的物种组成相似性来看，虽然土门－断头崖样带属于涪江水系，而茶山－九顶山样带和雁门沟－光光山样带属于岷江水系，但不同水系对该区物种组成的影响并不明显。三条样带中，草本层物种丰富度均远远大于灌木层和乔木层，而以乔木层物种丰富度最低；α－多样性指数随着海拔梯度的变化在土门-断头崖样带中呈现单一下降趋势，在茶山-九顶山样带表现为双峰模型，而在雁门沟-光光山样带则表现为不显著波动变化；均匀度指数在土门-断头崖样带呈现出单一下降的趋势，在雁门沟-光光山样带表现为凹形曲线，而在茶山-九顶山样带却无明显的变化规律。β－多样性指数在土门-断头崖样带和茶山-九顶山样带呈现出明显的波动状态，植被类型替代现象明显；而在雁门沟-光光山样带却并未有十分显著的转折点，因其水平植被带受到干扰，同海拔替代现象不显著。 3）九顶山西坡维管植物丰富度的海拔梯度格局 我们考察了九顶山西坡和两条垂直样带（土门－断头崖和雁门沟－光光山样带）的不同分类等级（包括科、属、种）和不同生活型物种（乔木、灌木、禾草、蕨类和其它草本）的丰富度沿着海拔梯度的分布。结果发现，物种的丰富度海拔梯度格局具有不同的模式，单一下降和中间膨胀格局依然是其主流。不同生活型的物种具有不同的丰富度格局，但是对于环境需求相似的类型具有较相似的丰富度格局。不同的丰富度格局可能由多因素导致，包括：气候，海拔跨度，面积，人为干扰等等。 4）九顶山西坡区系质量评估 我们尝试使用传统的区系质量评估方法对九顶山西坡的区系质量进行评估，并尝试使用一种新的区系质量评估体系对该区的区系进行评价。在九顶山西坡随着海拔梯度的上升，平均保守性系数在各条植被带中均呈现出逐渐上升的趋势。区系质量指数随着海拔的升高都表现为双峰模型，在植被交错区区系质量指数相对较高，而在海拔的两极，区系质量指数都很低。大部分地区使用新方法计算所得的加权平均保守性系数和区系质量指数都比传统方法计算的平均保收性系数和区系质量指数要高，说明在九顶山西坡的三条样带中，大部分地区都是那些保守性系数较高的物种占据优势，同时也表明九顶山西坡具有很高质量的区系和自然植被。 5）龙肘山种子植物区系的性质和特点 龙肘山种子植物区系的物种较为丰富，共有154 科，544 属，1156 种。科的优势十分明显，单种属和寡种属数量众多，说明本区系植物成分较为复杂、起源古老、物种多样性指数较高。地理成分复杂，分布类型多样，其中热带成分在总数量上高于温带成分，但是许多温带成分的属是该区植被的重要建群类群和优势类群，表现出明显的亚热带性质。 6）龙肘山生物多样性的现状和特点 在海拔梯度上，龙肘山地区无论是科、属、种的数量，还是不同等级分类单元之间的数量比，均呈现先升后降的趋势，并在中海拔地区达到峰值。物种多样性指数从总体上来说变化幅度不大，略有先升后降的趋势，在中海拔梯度物种多样性最高。乔、灌、草三层的多样性指数表现出乔木层<灌木层<草本层的特征；乔木层均匀度的变化很大，而灌木层和草本层均匀度的变化较小；灌木层均匀度的波动又强于草本层。β－多样性指数呈现单峰模式，中海拔地区最高。就龙肘山东、西坡物种多样性相比较而言，两者虽然在数值上交替上升，但是却体现出了较为一致的趋势，但西坡因受到干热河谷气候的影响，其平均气温要高于东坡，导致了东坡植物群落和物种的分布比西坡要低。在区系成分构成上，低山区的相同海拔段，西坡的热带亚热带成分所占的比例要比东坡高，这是因为西坡的平均气温比东坡稍高，导致了热带、亚热带物种分布更多。而随着海拔的上升，东、西两坡的气候、土壤等条件趋于一致，其植物区系成分的构成格局也趋于一致。 The Hengduan Mountain region is a very natural floristic region; it belongs toChina-Himalaya sub-region of Holarctic region in floristic subarea of China. The flora in this areais rich in family, genus and species; has a very complex composition of geographical elements;especially with high richness of endemic species and obvious substitution phenomenon. Thisregion as a hot-spot area of floristic and biodiversity, has fascinated biologists in the world for along time. The eastern range of Hengduan Mountain is the transition zone of China – Himalayaforest sub-region and China-Japan forest sub-region in floristic. The water systems are quitedifferent, Minjiang River in the north and Jishajiang River in the south grow quit different but alsoabundant plant species and vegetation resources. The similarity and correlativity of Minjiang River dry valleys and Jinshajiang River dry valleys have provided advantageous condition tocontrast flora and biodiversity between north and south. In the present study, the Jiuding Mountainlies in the north of Hengduan Mountain and belongs to Minjiang River, and the LongzhouMountain lies in the south of Hengduan Mountain and belongs to Jinshajiang River. In our study, we combined the methods of floristic research and biodiversity investigation toexplore the resources of plant species and vegetations; sampled with transects along the altitudinalgradients and also with transverse straps with similar elevation; collected the vascular plant specimen with sampling plots of ecology. We explored the plant species richness patterns alongaltitudinal gradients and discussed the underlying factors aroused these patterns; and used a novelmethod to assess the quality of Jiuding Mountain’s flora. All for a deeper comprehension of the plant recourses of this region; and provided feasible and reasonable suggestion for the protectionof resources. The results were as follows: 1 The characteristic of the flora of the west slope of Jiuding Mountain We had collected 1707 species of vascular plants belonging to 617 genera in 140 families inthe west slope of Jiuding Mountain，in which included 1616 seed plant species belonging to 572genera and 117 families. As for the composition of the areal types of the Families of seed plants,tropic components and temperate components are well-balanced, and percentage of tropicscomponents is higher than that of temperate ones for a litter bit. This shows the flora in the westslope of Jiuding Mountain has strong relationship with the tropic flora. But for the composition ofthe areal types of genera, temperate components have far exceeded the tropics ones, indicated thewhole flora with a conspicuous temperate character. Temperate components possess maximumproportion in the west slope of Jiuding Mountain, and many of them belong to constructivespecies and dominant species in the vegetation, are most important components in JiudingMountain’s Flora, also have embodied the temperate character of this area sufficiently. 2 Biodiversity patterns along altitudinal gradients in different vegetation transects in the westslope of Jiuding Mountain Based on the investigation of three vegetation transects (including Tumen-Duantouya transect,Chashan-Jiudingshan transect and Yanmengou-Guangguangshan Transect) in the west slope ofJiuding Mountain, we found the change of biodiversity along the altitude gradients displayedcertain regularity, but have differences among different transects. The three transects belong todifferent water systems; the Tumen-Duantouya transect belongs to Fujiang River, and the othertwo belong to Minjiang River. From the similarity of species compositions of different transects,we found different water system didn’t show obvious impact on the species composition. In all thethree transects, the species richness of herb layer was remarkably higher than shrub and tree layer,and the species richness of tree layer was the lowest one. With the increasing of the altitude, theline of α-diversity was monotonically decreasing curve in Tumen-Duantouya transect, andbimodal curve in Chashan-Jiudingshan transect, but in Yanmengou-Guangguangshan transectshowed a wave-like curve although not very obvious. Species evenness showed monotonicallydecreasing trends in Tumen-Duantouya transect, and very low at mid-altitude in Yanmengou-Guangguangshan transect, but in Chashan-Jiudingshan transect changed irregularly. Changes inβ-diversity corresponded with the transition of vegetation in the Tumen-Duantouya transect andChashan-Jiudingshan transect, and the curve of β-diversity along altitude had obvious turningpoint; but in Yanmengou-Guangguangshan transect had no obvious turning point, and thesubstitution phenomenon was not obvious, transverse vegetation straps distributed interlaced. 3 Richness patterns of vascular plant species along altitude in the west slope of Jiuding Mountain Direct gradient analysis and regression methods were used to describe the species richnesspatterns along the altitudinal for Mt. Jiuding, as well as separately for Tumen-Duantouya Transectand Yanmengou-Guangguangshan Transect. Altitudinal gradient of diversity of units at differenttaxonomic level (including Family, Genus and Species) and at different life form (including tree,shrub, pteridophyte, grass and other herb) were tested to find differences among the richnesspattern. We found altitudinal richness also shows different patterns, and both monotonicallydecreasing pattern and hump-shaped pattern can be founded in vascular species richness. Speciesin different life forms show different altitudinal patterns, but those species with similarrequirements to environmental conditions show similar richness patterns along altitudinalgradients. Different richness patterns can be aroused by different climate, different altitudinal span,area factor, anthropogenic factor and so on. 4 Floristic quality assessments in the west slope of Jiuding Mountain We used both the conventional method broadly adopted in the USA and the new one toassess the floristic quality in the west slope of Jiuding Mountain. The Mean Coefficient ofConservatism (MC) had the trend of increment along the altitudinal gradients. The FloristicQuality Index (FQI) was a bimodal curve with increasing of elevation; FQI got maximum valuesin the transition zones of different vegetations in the middle altitude, and had very low values atthe two end of elevation. In most areas of the west slope of the Jiuding Mountain, the resultscalculated using the new methods were higher than those using the conventional method. Thisindicated the dominant species of the communities had very high coefficients of conservatism inmost areas of Jiuding Mountain, and the communities are relatively kept pristine and the habitats very integrative. 5 The characteristic of the flora of Longzhou Mountain The flora of Longzhou Mountain has very abundant in species composition; there are about1156 species of seed plants belonging to 544 genera in 154 families. In which, twelve families with more than 20 species include totally 232 genera and 532 species, and form the majority of itsflora. The origin of its flora is old, monospecific genera and oligotypic genera amounts to 510 innumber, which constitute 93.75% of total number of genera. The geographical components arevarious in Longzhou Mountain, the majority of flora are temperate and pantropic ones. The tropiccomponents overtopped temperate components on genera quantity, but many temperatecomponents belong to constructive species and dominant species in the vegetation, and the wholeflora shows an obvious subtropical character. 6 Current situation and characteristic of biodiversity in Longzhou Mountain With the increasing of altitude, the number of species, genus, family and the ratios ofdifferent taxonomic levels all displayed a trend of descending after rising first, and peaked atmiddle height area. The change of α-diversity was not very acutely, with the trend of descendingafter rising first in some degree, the middle height area had highest α-diversity. As studying thetree layer, shrub layer and herb layer respectively, the Shannon-Wiener index was in followingorder: tree layer < shrub layer < herb layer; the change of evenness was more complicatedly thanthat of diversity, the tree layer changed acutely, but the shrub layer and herb layer fluctuatedsmoothly. Changes in β-diversity also showed the trend of descending after rising first. TheJaccard index and Cody index all peaked at the middle height forest area. As for the comparison ofplant diversity and evenness between the west and east slope, the numerical values ascendedalternatively, but the trend of changing was similar. The distribution of similar plant communitiesand species in east slope were lower than the west slope for the influence of Jinsha River DryValley. As for the composition of different floristic components, in lower altitude area of westslope, the tropic and sub-tropic plants had higher ratio than east slope’s and even could be equal tothe temperate plants. With the increasing of elevation, the floristic composition become morelikely between the east and west slope and temperate plants dominated the flora.

贡嘎山植物小枝功能性状在不同生活型和不同海拔间的比较研究

植物功能生态学研究不仅提供了植物生理生态学与生态系统生态学的连接，还为植物种群生活史对策研究提供了材料。Westoby 等 (2002) 提出了利用植物功能性状变量的主导维度来确定和量化植物生活史的生态适应策略。在他们所提出四个主导维度中，叶大小－小枝大小是研究相对较少的一维；其内部各组分的关系、对环境的响应，以及与其它重要维度的关系，目前的理解非常有限。 本研究以贡嘎山不同海拔不同功能群物种为研究对象，采用种间比较和系统发生独立性比较等研究方法，系统研究了植物的功能特征及其相关性在不同生境及不同功能群间的差异，旨在分析不同功能群物种的叶大小－小枝大小的成本和收益。其研究结果将有助于我们理解植物生活史对策的进化，进而理解物种共存和维持物种多样性的机制。主要研究结果如下： 1. 叶大小－小枝大小关系 小枝茎横截面积与单叶面积和总叶面积均呈异速生长关系，即总叶面积和单叶面积的增加比茎横截面积的增加速度快。但是，总叶面积和叶片干重的增加却基本上与小枝茎干重的增加等速。系统发生独立性比较研究的结果与此相一致。表明，在某一给定的茎投入时，至少大叶大枝物种不比小叶小枝物种在支撑叶面积和叶片干重方面具有优势。同时，在某一给定的小枝茎投入时，常绿阔叶物种比落叶阔叶物种支撑更少的叶面积。在茎干重与总叶面积的关系中，落叶复叶物种比落叶单叶物种具有更高的y轴截距，表明复叶物种比单叶物种在展叶面积方面更有效。复叶物种与单叶物种相比，通常具有较大的叶大小和小枝大小。 2. 叶大小－叶数量关系 叶大小与数量间在不同的叶片习性、不同的叶片形态以及不同的生境类型的物种间均存在稳定的负的等速生长关系，且这种关系在系统发生独立性比较时依然成立。然而，在某一给定的出叶强度 (单位小枝的叶数量) 时，常绿阔叶物种比落叶物种具有更小的叶面积。而在给定体积基础上的出叶强度时，落叶复叶物种的叶面积显著大于落叶单叶物种，且复叶物种比单叶物种具有更大的叶大小和更小的出叶强度。但是，叶大小与数量间的关系在不同的海拔间并没有显著的差异。 3. 小枝大小－总叶面积关系 在不同的生活型或不同的生境下，小枝上总叶面积与茎干重和小枝干重均呈正的异速生长关系，且斜率显著小于1.0，表明小枝上总叶面积的增加都不能赶上小枝及茎大小的增加。这种“收益递减”表明随着小枝干重的增加，光截取的收益递减。此外，叶面积比 (总叶面积与小枝干重的比值) 与单叶干重呈显著负相关关系，系统发生独立性比较的结果与此相一致。根据以上结果，可以推测，大叶的物种在质量较好的生境中出现，而群落内部小枝茎的寿命较长的物种可以拥有较大的叶片。 4. 叶片色素浓度－LMA关系 随着海拔的升高，阔叶木本植物和草本植物的叶片色素浓度减少，叶绿素a/b和类胡萝卜素/叶绿素比值以及比叶重 (LMA) 增加。然而，在草本植物中的色素浓度、色素比值和LMA的变化比阔叶木本植物的更明显。同时，LMA与叶片色素浓度呈负相关关系，但是在落叶物种中的LMA对色素浓度的影响比常绿阔叶物种更强烈。总之，草本植物的叶片特征对海拔梯度的变化似乎比木本植物更敏感，LMA对叶片色素的保护作用在落叶物种中比在常绿阔叶物种显得更重要。这些结果表明不同生活型物种可能采取不同的保护机制来降低叶绿体器官的损伤和增加他们的碳获取能力。 Studies on plant functional ecology not only bridge plant eco-physiology and ecosystem functioning, but also enrich plant population biology. As pointed out by Westoby et al (2002), plant life history strategies can be identified and quantified by four leading dimensions of variations in plant functional traits, i.e., seed size/output, leaf mass per area and leaf life span, plant height, and leaf size-twig size. Compared to the other dimensions, the cost/benefit of the leaf size-twig size spectrum has scarcely been analyzed in relation to environmental gradients and life form types, and the adaptive significance of this spectrum is not fully understood. In the present study, the relationships between functional traits of plant twigs are determined for the species with different life forms along an altitudinal gradient of Gongga Mountain with both cross-species analysis and evolutionary divergence analysis. The primary objective of this study is to examine the cost/benefit of leaf size-twig size in plants. The study results are supposed to provide insights into the understanding of the mechanism of species coexistences. The results are shown in the following. 1. The relationship between leaf size and twig size Twig cross-sectional area allometrically scaled with both individual leaf area and total leaf area supported by the twigs. However, the increase in total lamina mass/area was generally proportional to the increase in stem mass. These correlations between trait variations were significant in both interspecies analysis and phylogenetically independent comparison (PIC) analysis, which indicated that thick-twigged/large-leaved species, at least, do not have an advantage in supporting leaf/lamina area and lamina mass for the same twig stem investment than thin-twigged/ small-leaved species. Meanwhile, the evergreen broad-leaved species supported a smaller leaf area for the same twig stem investment in terms of both cross-sectional area and stem mass than the deciduous species. The deciduous compound-leaved species have a higher y-intercept in the scaling relationship of twig stem mass versus total leaf area than the deciduous simple-leaved species, indicating that compound-leaved species were more efficient in displaying leaf area. The compound-leaved species were larger in both leaf size and twig size than their counterpart in the present study. 2. The relationship between leaf size and leaf number Significantly negative and isometric scaling relationships between leaf size and leafing intensity (leaf number per twig mass or volume) were found to be consistently conserved across species independent of leaf habit, leaf form and habitat type. The negative correlations between leaf size and leafing intensity were also observed across correlated evolutionary divergences. However, leaf area was smaller in the evergreen broad-leaved species at a given leafing intensity than in the deciduous species. The deciduous compound-leaved deciduous species were higher in leaf area than deciduous simple-laved species at a given volume-based leafing intensity. Moreover, the compound-leaved deciduous species were larger in leaf size but smaller in leafing intensity than their simple counterparts. No significant difference was found in the scaling relationships between altitudes. 3. The relationship between twig size and total leaf area Leaf area was found to scale positively and allometrically with both stem and twig mass (stem mass plus leaf mass) with slopes significantly smaller than 1.0, independent of life form and habitat type, indicating that the increase in total leaf area fails to keep pace with increasing twig size and stem size. This ‘diminishing returns’ suggests that the benefit of light intercept decreased with increasing twig mass. Moreover, the leaf area ratio (the ratio of total leaf area to stem or twig mass) correlated negatively with individual leaf mass. The results of PIC were consistent with the correlations. According to the results, it is speculated that large-leaved species may be favored when habitat is good and when stem longevity are long within community. 4. The relationship between leaf pigment concentrations and leaf mass per area With increasing altitude, the concentrations of pigments decreased, but the ratios of chlorophyll a/b and carotenoid/chlorophyll, and LMA increased, in both the broad-leaved woody species and herbaceous species groups. However, the changes in the pigment concentrations, ratios and LMA were more profound in the herbaceous species than in the woody species. In addition, pigment concentrations were negatively correlated with LMA in each life form type and in the pooled dataset. However, the LMA effect on leaf pigment concentrations was more profound in the deciduous species than in the evergreen braode-leaved species. In general, herbaceous species seemed more sensitive to the increasing altitude compared to woody species, and LMA seemed to be a more important mechanism for protecting leaf pigments in deciduous species than in evergreen broad-leaved species. These results suggested that the species with different life forms may employ different protective mechanisms to decrease the chloroplast apparatus damage and increase their carbon gain.

Phycobilisomes linker family in cyanobacterial genomes: divergence and evolution

Cyanobacteria are the oldest life form making important contributions to global CO2 fixation on the Earth. Phycobilisomes (PBSs) are the major light harvesting systems of most cyanobacteria species. Recent availability of the whole genome database of cyanobacteria provides us a global and further view on the complex structural PBSs. A PBSs linker family is crucial in structure and function of major light-harvesting PBSs complexes. Linker polypeptides are considered to have the same ancestor with other phycobiliproteins (PBPs), and might have been diverged and evolved under particularly selective forces together. In this paper, a total of 192 putative linkers including 167 putative PBSs-associated linker genes and 25 Ferredoxin-NADP oxidoreductase (FNR) genes were detected through whole genome analysis of all 25 cyanobacterial genomes (20 finished and 5 in draft state). We compared the PBSs linker family of cyanobacteria in terms of gene structure, chromosome location, conservation domain, and polymorphic variants, and discussed the features and functions of the PBSs linker family. Most of PBSs-associated linkers in PBSs linker family are assembled into gene clusters with PBPs. A phylogenetic analysis based on protein data demonstrates a possibility of six classes of the linker family in cyanobacteria. Emergence, divergence, and disappearance of PBSs linkers among cyanobacterial species were due to speciation, gene duplication, gene transfer, or gene loss, and acclimation to various environmental selective pressures especially light.