荆条叶性状对野外不同光环境的表型可塑性

光照是影响植物生长和分布的重要环境因子。对生长在野外5种不同光环境下(林外、阔叶林林缘、阔叶林林下、针叶林林窗和针叶林林下)的荆条的叶片进行取样研究,通过对光合作用光响应曲线、叶绿素荧光、叶绿素含量、叶片氮磷含量以及叶片形态的测量,来反映荆条对不同光环境的表型可塑性。研究结果表明,荆条叶片对于野外不同的光环境具有很好的适应机制,叶片功能性状受到结构性状的调节。低光下通过高的比叶面积(SLA)、单位质量叶绿素含量、光系统II最大量子产量,低的暗呼吸速率、光饱和点、光补偿点、叶绿素a,b的比值来提高对光能的利用效率,维持生长;高光下则通过与SLA有关的叶片结构的变化对光合作用进行调节。大多数的叶性状只受到日光照总量的影响,SLA的大小与日最高光强有关,可以对不同日变化模式的光照做出迅速的响应,是适应不同光照的敏感指标。尽管光照是不同光环境下影响荆条叶性状的主要环境因子,土壤养分含量同样会对叶性状产生影响,高土壤养分下的高叶长与叶柄长的比值体现了植物对资源获取和支撑结构之间分配的权衡。     

闽楠叶片功能性状及表型可塑性对其与杉木混交的响应

慢生（闽楠）与速生（杉木）树种混交后,植物是如何改变功能性状来适应环境,在资源获取与分配权衡中来实现共存？是人工林精准提质改造过程中的关键问题,研究了闽楠（Phoebe bournei）与杉木（Cunninghamia lanceolate）混交后,其叶厚（LT）、叶面积（LA）、比叶面积（SLA）、碳含量（LC）、氮含量（LN）、磷含量（LP）和氮磷比（N：P）7项性状指标的差异,探讨其各性状间的变异大小及其相关关系。结果表明：（1）与闽楠纯林相比,混交林闽楠叶片叶面积、比叶面积、叶碳含量、叶氮含量和氮磷比分别增加了16.78%、8.50%、3.12%、21.38%和17.61%,而叶厚与叶磷含量减少了8.80%和25.87%,除叶碳含量差异不显著,其他6项功能性状差异性均达到显著（P<0.05）。（2）混交使闽楠叶LC、LN、LP含量与LT、LA、SLA相关性均发生明显的变化,对其叶厚、叶面积、比叶面积及其交互作用对叶片C：N、C：P、N：P产生一定的影响,表明混交闽楠叶功能性状间的相关关系发生了适应性调整;（3）闽楠主要叶片功能性状的表型可塑性指数分布在0.04-0.33之间,叶厚、叶面积、比叶面积和氮磷比的可塑性变化不敏感（PPI<0.20）,叶氮含量、磷含量的可塑性变化较敏感（PPI>0.20）,其大小排序为LP > LN > N：P > LA > SLA > LT > LC。以上结果表明了闽楠杉木混交造林模式对闽楠叶形态性状可塑性变化影响较小,没有受到生长空间和光资源的限制,混交是一种较好的造林模式。但闽楠叶氮、磷含量可塑性变化在混交模式中十分敏感,表明生长过程中可能会受到N、P的限制,在培育过程中应注意N肥和P肥的及时补充。这一研究结果,将为今后速生树种与珍贵树种混交造林模式研究提供理论与数据支撑。     

Seasonal leaf dynamics across a tree density gradient in a Brazilian savanna

Interactions between trees and grasses that influence leaf area index (LAI) have important consequences for savanna ecosystem processes through their controls on water, carbon, and energy fluxes as well as fire regimes. We measured LAI, of the groundlayer (herbaceous and woody plants <1-m tall) and shrub and tree layer (woody plants >1-m tall), in the Brazilian cerrado over a range of tree densities from open shrub savanna to closed woodland through the annual cycle. During the dry season, soil water potential was strongly and positively correlated with grass LAI, and less strongly with tree and shrub LAI. By the end of the dry season, LAI of grasses, groundlayer dicots and trees declined to 28, 60, and 68% of mean wet-season values, respectively. We compared the data to remotely sensed vegetation indices, finding that field measurements were more strongly correlated to the enhanced vegetation index (EVI, r ²=0.71) than to the normalized difference vegetation index (NDVI, r ²=0.49). Although the latter has been more widely used in quantifying leaf dynamics of tropical savannas, EVI appears better suited for this purpose. Our ground-based measurements demonstrate that groundlayer LAI declines with increasing tree density across sites, with savanna grasses being excluded at a tree LAI of approximately 3.3. LAI averaged 4.2 in nearby gallery (riparian) forest, so savanna grasses were absent, thereby greatly reducing fire risk and permitting survival of fire-sensitive forest tree species. Although edaphic conditions may partly explain the larger tree LAI of forests, relative to savanna, biological differences between savanna and forest tree species play an important role. Overall, forest tree species had 48% greater LAI than congeneric savanna trees under similar growing conditions. Savanna and forest species play distinct roles in the structure and dynamics of savanna–forest boundaries, contributing to the differences in fire regimes, microclimate, and nutrient cycling between savanna and forest ecosystems.     

Leaf area index (LAI) map of a protected area within the caldera of Vico Lake (Italy)

ABSTRACT

Structural traits of the vegetation types and plantations occurring in a protected area within the caldera of Vico Lake (Italy) were analysed. There were significant correlations among structural traits, at leaf and stand level. Leaf area index (LAI) and specific leaf area (SLA) were the most significantly correlated traits. LAI rose according to stand plant density, tree size and SLA; the highest LAI value monitored in the Fagus sylvatica L. forest was justified by the largest tree size (28.9±2.8 m height and 53±15 cm diameter) and the highest SLA (212±23 cm² g^-1). The main traits determining the variations in leaf structure among species were analysed by Principal Component Analysis (PCA). The LAI values were used to realise a map allowing us to delimit high LAI values (4.1–5.0), corresponding to the F. sylvatica forest and to the F. sylvatica forest with the sporadic presence of Quercus cerris L. and Castanea sativa Miller, mean LAI values (classes 3.1–4.0) corresponding to Corylus avellana L. plantations and to the Phragmites australis (Cav.) Trin. vegetation type, low LAI values (classes 2.6–3.0) corresponding to Q. cerris forests and C. sativa plantations.     

江西千烟洲人工针叶林下狗脊蕨群落生物量

 根据野外调查和实验分析研究了江西省千烟洲人工针叶林下狗脊蕨（Woodwardia japonica）群落的生物量、细根生物量、净初级生产力(Net primary productivity, NPP)、 比叶面积（Specific leaf area, SLA） 和叶面积指数（Leaf area index, LAI）等。通过叶片参数和地上生 物量的相关关系建立了狗脊蕨单株地上生物量估算模型,分别 为W1=0.021H^1.545（R²=0.790）和W1=2.518（D²H）^{0 .616}（R²=0.894;H为株高 ,D为地径）。人工针叶林下灌草层地上生物量为367.8 g&;#8226;m^－2（52～932 g&;#8226;m^－2）,凋落物为1 631 g&;#8226;m^－2（672～2 763 g&;#8226;m^－2）,分别占 乔木层地上生物量的4.7%（1.55%～13.2%）和20.7%（7.6%～32.1%）。狗脊蕨群落地上生物量和NPP分别为266.6 g&;#8226;m^－2和88.67 g&;#8226;m^－2&;#8226;a ^-1 ,其中狗脊蕨种群占73.7%;地下生物量为212.6 g&;#8226;m^－2。狗脊蕨的SLA和叶干物质含量（Leaves day mutter content, LDMC）分别为144.0 cm²&;#8226;g^-1和31.99%,二者之间呈显著负相关;最佳叶面积估算模型为S=21.922 6-0.152L²+0.000 9L³（9.0≤L（叶片长度）≤23.5;1.4≤W （ 叶片宽度）≤5.9）。狗脊蕨种群的LAI为1.8。土壤含水量对狗脊蕨生物量有显著影响。群落生物量与土壤有机质和全氮含量正相关     

祁连山中部优势灌木物种叶功能性状参数变化特征

植物叶功能性状是连接植物与外界环境的重要桥梁,是探索植物适应环境、进行全球气候变化研究的指标,也是生态水文模型重要的输入参数。通过高时间分辨率样品的采集结合图像处理技术,对祁连山中部优势物种金露梅(Dasiphora fruticosa)和鬼箭锦鸡儿(Caragana jubata)叶功能性状变化特征进行研究,结果表明：叶面积(LA)从生长初期到生长末期发生明显变化,且2020年6—7月初灌木叶面积变化最为明显;比叶面积(SLA)分别在76—157 cm²/g之间和120—217 cm²/g之间,金露梅SLA平均值(123 cm²/g)<鬼箭锦锦鸡儿SLA平均值(176 cm²/g);在生长初期金露梅的叶面积指数(LAI)明显大于鬼箭锦鸡儿,金露梅和鬼箭锦鸡儿的叶面积指数随时间的变化都符合三次函数;生物量与基径和高度的乘积呈显著性相关,最优回归模型均为幂函数;地上生物量与叶功能性状参数在不同阶段的模拟方程均不同,地上总生物量与叶生物量在生长期的最优选择模型分别呈S型函数和幂函数,金露梅的单株地...     

Leaf trait associations with environmental variation in the wide‐ranging shrub Dodonaea viscosa subsp. angustissima (Sapindaceae)

Intra‐species variation in specific leaf area (SLA) and leaf area (LA) provides mechanistic insight into the persistence and function of plants, including their likely success under climate change and their suitability for revegetation. We measured SLA and LA in 101 Australian populations of the perennial shrub Dodonaea viscosa (L.) Jacq. subsp. angustissima (narrow‐leaf hop‐bush) (Sapindaceae). Populations were located across about a 1000 km north–south gradient, with climate grading from arid desert to mesic Mediterranean. We also measured leaves from 11 populations across an elevational gradient (300–800 m asl), where aridity and temperature decrease with elevation. We used regression and principal component analyses to relate leaf traits to the abiotic environment. SLA displayed clinal variation, increasing from north to south and correlated with latitude and the first principal component of joint environmental variables. Both SLA and LA correlated positively with most climatic and edaphic variables. Across latitude, LA showed more variability than SLA. Changes in leaf density and thickness may have caused the relative stability of SLA. Only LA decreased with elevation. The absence of a SLA response to elevation could be a consequence of abiotic conditions that favour low SLA at both ends of the elevational gradient. We demonstrated that the widely distributed narrow‐leaf hop‐bush shows considerable variability in LA and SLA, which allows it to persist in a broad environmental envelope. As this shrub is widely used for revegetation in Australia, South America and the Asia‐Pacific region, our results are consistent with the notion that seed used to revegetate mesic environments could be sourced from more arid areas to increase seed suitability to future climate change.     

Patterns in specific leaf area and the structure of a temperate heath community

Relationships between the distribution and specific leaf area (SLA: leaf area per unit dry mass) of six heath (Ericaceae) species were investigated along an environmental gradient between peat bogs and conifer forest in British Columbia, Canada. I asked whether patterns in SLA could help to identify the processes shaping plant distributional patterns. Specifically, I assessed whether (i) species’ distributions across the environmental gradient are correlated with SLA (ii) relationships between plant distributional patterns and SLA are similar among bogs with different shrub species (iii) intraspecific patterns in SLA parallel interspecific relationships between distributions and SLA, and (iv) intraspecific patterns are environmentally determined. Results showed that distributional patterns were often correlated with SLA; species with lower SLA were more abundant towards the centre of bogs, while species with higher SLA were more abundant in forest. Intraspecific patterns in SLA paralleled distributional patterns across the gradient; individuals located towards the centre of bogs had lower SLA than those growing in forest. A transplantation experiment showed that plants typically altered their SLA according to local environmental conditions. However, one bog showed no relationship between species’ distributions and SLA. This bog lacked the two species with lowest SLA, which typically occurred at the centre of other bogs. In their absence, species with higher SLA that typically occurred in forest increased in abundance towards the centre of the bog, where they obtained lower values of SLA. Therefore, while distributional patterns were often closely associated with SLA, plasticity in SLA was associated with increased breadth of species’ distributions across the gradient. Overall results indicate SLA may serve as a useful proxy for a range of life history traits to help elucidate the processes structuring plant communities.     

Leaf plasticity in response to light of three evergreen species of the Mediterranean maquis

Morphological, anatomical, biochemical and physiological traits of sun and shade leaves of adult Quercus ilex, Phillyrea latifolia and Pistacia lentiscus shrub species co-occurring in the Mediterranean maquis at Castelporziano (Latium) were studied. Fully expanded sun leaves had 47% (mean of the three species) greater leaf mass area (LMA) and 31% lower specific leaf area (SLA) than shade leaves. Palisade parenchyma thickness contributed on an average 42% to the total leaf thickness, spongy layer 43%, upper epidermal cells 5%, and upper cuticle thickness 3%. Stomatal size was greater in sun (25.5 μm) than in shade leaves (23.6 μm). Total chlorophyll content per fresh mass was 71% greater in shade than in sun leaves, and nitrogen content was the highest in sun (13.7 mg g⁻¹) than in shade leaves (11.8 mg g⁻¹). Difference of net photosynthetic rates (P _N) between sun and shade leaves was 97% (mean of the three species). The plasticity index (sensu Valladares et al., New Phytol 148:79–91, 2000a) was the highest for physiological leaf traits (0.86) than for morphological, anatomical and biochemical ones. Q. ilex had the highest plasticity index of morphological, anatomical and physiological leaf traits (0.37, 0.28 and 0.71, respectively) that might explain its wider ecological distribution. The higher leaf plasticity of Q. ilex might be advantageous in response to varying environmental conditions, including global change.     

中国温带典型森林植物比叶面积的空间格局及其影响因素

比叶面积(SLA)能够反映植物自身生长对策、对光能的捕获能力、对外界环境变化的适应和对可利用资源的分配策略,对植物的生境适应状况和群落的自然演替程度也起到重要的指示作用。为了深入了解温带森林植物SLA随空间变化的变异特征及其影响因素,跨越1200 km选取中国东北部12个典型温带森林(寒温带兴安落叶松林、温带红松针阔混交林和暖温带落叶阔叶栎林),通过对样地内物种进行系统性的调查,分析了植物SLA在空间上的变化规律及环境因素的影响效应。结果显示：中国温带森林植物SLA范围为2.02—99.65 m~2/kg(均值为34.18 m~2/kg),其中乔木SLA范围为2.02—58.74 m~2/kg(均值为21.32 m~2/kg),灌木SLA范围为2.88—99.65 m~2/kg(均值为31.60 m~2/kg),草本SLA范围为4.66—98.53 m~2/kg(均值为38.75 m~2/kg)。SLA在不同森林类型之间差异显著,具体表现为：温带红松针阔混交林>暖温带落叶阔叶栎林>寒温带兴安落叶松林。SLA受到气候因素和土壤因素的影响,其中随着年均降水、土壤碳氮含量的增加显...     

利用凋落物法和林木因子模拟小兴安岭阔叶红松林叶面积指数

叶面积指数(LAI)是研究森林生态系统生理生态进程中关键的结构参数之一。目前,凋落物法是在非破坏性条件下能直接测定森林生态系统LAI的最有效的方法,然而将凋落叶按树种分类增加了该方法的实施难度。平均优势度模型、林分优势度模型和局域优势度模型基于凋落物法和林木因子(如胸高断面积basal area,BA;坐标)能精确地预测落叶阔叶林的LAI,而这些模型是否适用于针阔混交林仍未进行验证。以小兴安岭阔叶红松林(Pinus koraiensis)为研究对象,先利用凋落物法测定其LAI,依此为参考对3种模型预测LAI的有效性进行验证,并以红松、冷杉(Abies nephrolepis)、紫椴(Tilia amurensis)、五角槭(Acer mono)、枫桦(Betula costata)和裂叶榆(Ulmus laciniata)为例,探讨了基于凋落物法测定的LAI与BA的相关关系。结果表明:平均优势度模型不适于预测针阔混交林的LAI;林分优势度模型预测效果较好,精度达86%;局域优势度模型预测效果最优,精度高于90%。然而,为准确测定阔叶红松林的LAI,应最少选择测定8个主要树种的比叶面积。基于凋落物法测定的6个树种的LAI与其BA均显著相关(P0.01),最小R2为0.67。研究结果可为快速、准确地测定针阔混交林的LAI提供依据,为非破坏性条件下建立树种的LAI与其BA的相关关系提供参考。     

Leaf litterfall,leaf area index,and radiation transmittance in cypress wetlands and slash pine plantations in north-central Florida

The seasonal dynamics of leaf litterfall and leaf area index (LAI, all-sided basis), light penetration and the vertical distribution of surface area index, and the feasibility of estimating LAI from radiation transmittance were studied from April 1993 to March 1994 in the canopies of three cypress (Taxodium ascendens) wetlands and their surrounding slash pine (Pinus elliottii) uplands in Florida flatwoods. Annual leaf litterfall ranged from 324 to 359 g m^–2 in the wetlands, which was very close to the average for 11 sites throughout Florida of 340±26 g m^–2. The seasonal pattern of the normalized LAI obtained for the dominant tree species in the ecosystems could be used to construct the seasonal dynamics of LAI at the ecosystem scale. The vertical distribution of surface area index in the wetlands was significantly different from that in the surrounding pine uplands. The maximum LAI of cypress wetlands in this area was about 8 m² m^–2, which was higher than the maximum of slash pine plantations of 6 m² m^–2. Cypress leaves were strongly erectophile in space. Results showed that the LAI-2000 canopy analyzer could generally be used to estimate forest LAI, whether the forest canopy was closed or not, if an overall clumping index of 2.00 was applied. However, as LAI decreased, the relative error contained in the radiation-based LAI estimates increased. This indicated that foliage clumping at the stand scale was more important than that at the tree or branch scale.     

科尔沁沙地东南部地区主要植物叶片性状及其相互关系

选取科尔沁沙地东南部地区23种主要植物,将其划分成草本、灌木和乔木3种生长型,并分别测定其叶片鲜重(FW)、干重(DW)、叶干物质含量(DMC)、面积(AR)、比叶面积(SLA)和厚度(TH)等6项叶片性状因子。结果表明,草本植物的叶片性状比灌木和乔木变异大;平均SLA和DMC草本<灌木<乔木,DW反之,而TH则没有明显的变化。方差分析发现,除DW和TH外,SLA和DMC在不同生长型中的变化显著,并且SLA与DMC呈显著负相关,说明SLA和DMC是在植物资源利用分类轴上划分植物种类的最佳变量。对于厚度,还需进一步进行研究。     

Light Absorption and Competition in Mixed Communities of Hordeum Leporinum-Euphorbia Scordifolia

The effect of Euphorbia scordifolia and Hordeum leporinum competition on leaf area development, radiant energy absorption, and dry matter production was evaluated in a field experiment. Profile measurements (0-0.3, 0.3-0.6, 0.6-0.9, and >0.9 m above ground) of absorbed photosynthetically active radiation (APAR) and leaf area index (LAI) by species were taken at four densities of E. scordifolia (0, 1, 4, and 12 plants per m²). APAR calculated for H. leporinum in mixed communities was 79, 77, and 49 % of the APAR in H. leporinum and LAI was reduced to 81, 65, and 37 %. LAI of H. leporinum was concentrated in the 0.3-0.6 m layer, while the taller E. scordifolia plants had the greatest LAI above 0.6 m. By absorbing radiant energy in the upper canopy, E. scordifolia reduced APAR penetrating to H. leporinum. Measurements of net photosynthetic and transpiration rates, leaf temperature, and stomatal conductance confirmed the importance of competition for PAR for plant growth and metabolism. This revised version was published online in June 2006 with corrections to the Cover Date.     

Growth, radiation use efficiency and yield potential of enset (Ensete ventricosum) at different sites in southern Ethiopia

Knowledge on the physiological parameters that determine the growth of enset (Ensete ventricosum) and on how these parameters develop over time and affect yield under field conditions is scarce. Field experiments were carried out at three sites in southern Ethiopia using suckers of several clones to generate crop physiological parameters and to describe the time course of leaf number, leaf area and plant height. Yield potentials at different sites were estimated using these parameters and weather data, and compared with the actual yield. Plant height and LAI increased faster at Awassa and Areka than at Hagereselam because of a higher leaf appearance rate associated with temperatures being closer to the optimum. The trend in plant height was best described by a logistic function, whereas the trend in LAI was best described by a logistic function only at Awassa and Areka. A high leaf appearance rate (0.18 leaves day^?1) during early growth at Awassa and Areka made it possible that leaves that were senesced during unfavourable climatic conditions could be rapidly replaced without strong fluctuation in leaf area index. At Hagereselam, however, the rate of leaf appearance (0.09 leaves day^?1) was too small to compensate for the decline in the number of green leaves per plant during adverse conditions and thus LAI fluctuated over the whole growing period. The trend in fraction of PAR intercepted was best described by a generalised logistic function. At 300 days after transplanting the suckers, LAI reached a value of 4.5 and enset clones intercepted 92–97% of incoming PAR. The mean extinction coefficient was between 0.56–0.91 and radiation use efficiency (RUE) ranged from 1.43–2.67 g MJ^?1. Dry matter kocho yield potentials of 17.1 to 33.9 t ha‐1 yr‐1 were estimated for enset clones. Important yield potential differences existed between clones mainly because of differences in radiation use efficiency that was probably partly associated with viral infection. The average ratio of actual yield:yield potential (0.24) was low mainly because of large losses associated with traditional fermentation techniques, yield reducing cultivation methods such as repetitive transplanting and leaf pruning, presence of diseases, lack of adequate fertilisation and shortage and uneven distribution of rainfall.     

不同光照强度对入侵植物薇甘菊（Mikania micrantha）和飞机草（Chromolaena odorata）生长及生物量分配的影响

外来植物入侵严重威胁着当地生物多样性和生态系统功能,引发巨大经济损失,已成为日益严重的全球性问题。光是热带和亚热带森林生态系统植物生长最重要的限制性资源之一,对光的捕获和利用直接影响植物在自然生态系统中的生存和适合度。本研究以华南地区危害严重的入侵植物薇甘菊(Mikania micrantha)和飞机草(Chromolaena odorata)为研究对象,对比二者生长、生物量分配及叶片特征对光照强度变化的响应,从而验证假设:外来植物入侵力受有效光辐射的限制,光照是影响不同演替阶段林型具有不同可入侵性的重要原因之一。研究结果表明,3%—60%全光照下两种外来植物均可存活,并显示较灵活的生物量分配策略,可见其对光照具有广适性,为其广泛分布提供生态学基础。低光严重抑制了两种外来植物的生物量积累,这可能是导致演替后期季风林入侵现象少的主要原因之一。对比两种植物叶片特征对光照强度变化的响应,高光下薇甘菊SLA降低,LAR、LARMR减小,叶片变小变厚,有利于植株保持强光下的水分平衡;低光下薇甘菊增加SLA和LAR,叶片变薄变大,增大对光的截获面积,以实现对光强减弱的适应。相比薇甘菊,3种光照处理对飞机草的SLA、LAR、LARMR无显著影响。以上结果提示:(1)光照影响所在群落对外来植物入侵的抵抗力;(2)攀援植物薇甘菊较丛生型草本飞机草对变化的光环境在叶片水平上具有更高的形态可塑性,有效寻觅光资源。     

Subtropical montane tree litter decomposition: Links with secondary forest types and species' shade tolerance

Abstract Litter decomposition plays an important role in secondary forest recovery in the tropics. In this study we assessed the decomposition rates of tree litter in species from different secondary forest types and with different shade tolerances. The three secondary forest types analysed are related to the effects of different previous land use intensities. The typical forest type (TYP) is related to low land use intensity, Alnus acuminata‐dominated forest (ALN) type is related to medium land‐use intensity and Amomyrtella güili‐dominated forest type (AMO) is related to high land use intensity. The effect of shade tolerance was assessed using maximum height of each species as an indicator of its light requirements. Associations with leaf functional traits such as specific leaf area (SLA), and tensile strength (LTS) were also assessed. We found that leaves of species from the TYP forest type decompose faster than those of the ALN and AMO forest types. These changes were consistent with differences in the SLA of the species, which was higher in the TYP forest type than in the ALN and AMO forest types. SLA, LTS and decomposition were not significantly correlated with tree maximum height. Our results show that the secondary forest types, which are related to land use intensities prior to abandonment have an important influence on litter decomposition. This implies potential long‐term effects on soil properties and species composition.     

Leaf allometry and prediction of specific leaf area (SLA) in a sugar beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.) cultivar

Sugar beet cv. Rizor was grown for five growing seasons (2002–2006) in field conditions in Thessaly, central Greece. A total of 55 samplings took place during the growing seasons and allometric growth of the leaves was monitored. Highly significant (p<0.001) quadratic relationships were found between individual leaf mass (LM), individual leaf area (LA), aboveground dry biomass (ADB), and leaf area index (LAI). Only the LM-LA relationship (LA = 43.444 LM² − 10.693 LM + 118.34) showed a relatively high r ² (0.63) and thus could be used for prediction of LA. Specific leaf area (SLA) was significantly related with leaf water content (LWC) (SLA = 26 279 LWC² − 44 498 LWC + 18 951, r ² = 0.91, p<0.001) and thus LWC could be a good indirect predictor of SLA in this cultivar.     

从异龄叶性状分析几种常绿阔叶植物变异与关联

该研究从个体与物种两个水平分析福建省鬼洞山中亚热带常绿阔叶次生林中七种阔叶树种异龄叶的平均叶面积(MLA)、比叶面积(SLA)和叶干物质含量(LDMC)三个性状的变异及关联,探讨叶性状物质分配策略对植物生活策略优化的限制性影响。结果表明:(1)对七种阔叶树种的个体和物种水平变异系数而言,均为MLA(82.9%;76.9%)SLA(38.9%;35.5%)LDMC(25.4%;23.8%);在个体和物种水平上当年生叶片MLA变异系数(71.5%;64.0%)小于往年生叶片(72.2%;65.8%),SLA、LDMC值则相反。(2)在个体和物种水平,当年生叶MLA对往年生叶MLA变异的解释率分别为50.1%和61.5%,当年生叶SLA对往年生叶SLA变异的解释率分别为56.6%和77.0%,当年生叶LDMC对往年生叶LDMC变异的解释率分别为51.7%和68.3%。(3)7种亚热带常绿阔叶植物异龄叶MLA、SLA与LDMC变化规律说明,当年生叶与往年生叶投资相同干物质,当年叶可形成更大的叶面积,且叶面积建成的消耗较往年叶小。研究认为,异龄叶性状在异龄叶间存在变异与关联,叶面积形成过程中生物量建成与消耗的协调可能影响植物叶片的发育。     

井冈山鹿角杜鹃群落灌木层植物叶功能性状对海拔梯度的响应

为揭示鹿角杜鹃(Rhododendron latoucheae)群落灌木层植物叶功能性状及其对环境变化的响应趋势,对分布于井冈山不同海拔梯度鹿角杜鹃群落灌木层植物的叶功能性状进行了研究。结果表明,海拔梯度对灌木植物的叶功能性状有显著影响。随海拔的升高,叶片的干物质含量(LDMC)、厚度(LT)、氮含量(LNC)、磷含量(LPC)呈显著上升趋势,比叶面积(SLA)和N/P呈显著下降趋势,而叶大小(LS)呈先上升后下降的变化趋势;灌木植物叶片的LDMC与SLA、LS呈负相关,与LT、LNC、LPC呈正相关;SLA与LT、LNC呈负相关;LS与LT呈负相关;LNC与LPC呈正相关;N/P与LPC呈负相关;环境因子对灌木植物叶功能性状有重要影响,除受海拔的影响外,LPC、N/P还受坡位的影响,LS、LNC则分别还受到坡向和坡度的影响。因此,井冈山地区鹿角杜鹃群落灌木层植物通过改变叶功能性状来适应海拔和其它环境因子的变化。