共查询到20条相似文献,搜索用时 31 毫秒
1.
J. Gurevitch 《Genetics》1992,130(2):385-394
Achillea lanulosa has complex, highly dissected leaves that vary in shape and size along an altitudinal gradient. Plants from a high and an intermediate altitude population were clonally replicated and grown in a controlled environment at warm and cool conditions under bright light. There were genetic differences among populations and among individuals within populations in leaf size and shape. Heritabilities for leaf size and shape characters were moderate. Leaves of the lower altitude population were larger and differed from the higher altitude plants in both coarse and fine shape. Plastic response to temperature of the growth environment paralleled the genetic differentiation between low and high altitude populations. There was no apparent trade-off between genetic control over morphology and the capacity for directional plastic response to the environment. Differences in leaf dissection and size at contrasting altitudes in this species are the result of both genetic divergence among populations and of acclimative responses to local environments. 相似文献
2.
Both phenotypic plasticity and genetic determination can be important for understanding how plants respond to environmental change. However, little is known about the plastic response of leaf teeth and leaf dissection to temperature. This gap is critical because these leaf traits are commonly used to reconstruct paleoclimate from fossils, and such studies tacitly assume that traits measured from fossils reflect the environment at the time of their deposition, even during periods of rapid climate change. We measured leaf size and shape in Acer rubrum derived from four seed sources with a broad temperature range and grown for two years in two gardens with contrasting climates (Rhode Island and Florida). Leaves in the Rhode Island garden have more teeth and are more highly dissected than leaves in Florida from the same seed source. Plasticity in these variables accounts for at least 6–19 % of the total variance, while genetic differences among ecotypes probably account for at most 69–87 %. This study highlights the role of phenotypic plasticity in leaf-climate relationships. We suggest that variables related to tooth count and leaf dissection in A. rubrum can respond quickly to climate change, which increases confidence in paleoclimate methods that use these variables. 相似文献
3.
The shrub Encelia farinosa (Asteraceae) exhibits geographic variation in aboveground architecture and leaf traits in parallel with environmental variation in temperature and moisture. Measurements of plants occurring across a natural gradient demonstrated that plants in desert populations produce smaller, more pubescent leaves and are more compact and branched than plants in more mesic coastal environments. This phenotypic variation is interpreted in part as adaptive genetic differentiation; small size and pubescence reduce leaf temperature and thus increase water-use efficiency but at the cost of lower photosynthetic rate, which results in slower growth and more compact growth form. We explored the basis of phenotypic variation by planting seed offspring from coastal and desert populations in common gardens in both environments. Phenotypic differences among populations persisted in both common gardens, suggesting a genetic basis for trait variation. Desert offspring outperformed coastal offspring in the desert garden, suggesting superior adaptation to hot, dry conditions. Herbivore damage was greater for all offspring in the coastal garden. Phenotypic characters also showed plastic responses; all offspring had smaller, more pubescent leaves and more compact growth form in the desert garden. Our results confirm that leaf size and pubescence are heritable characters associated with pronounced variation in plant architecture. 相似文献
4.
KEN OYAMA 《Botanical journal of the Linnean Society. Linnean Society of London》1996,120(3):243-256
Phenotypic and genetic variation within and among eight populations of Arabis serrata are documented in this study. This species shows great morphological variation throughout its geographical distribution in Japan. Plants are located in habitats with different types of soils and degree of disturbance. Half-sibs progenies from eight populations were collected and cultivated in a garden experiment. Nine morphological traits representing size and shape of rosette leaves were recorded. Univariate analyses of measured traits showed that phenotypic means differed among populations for all characters. Leaves of plants from disturbed habitats had the longest petioles (lanceolate) and plants from limestone habitats showed the most roundness in leaf shape (ovate). The northernmost populations always revealed the smallest leaves. Multivariate principal component analyses also showed that leaf shape and size varied among populations. The first three principal components explained 98.5% of the variation. Coefficients of variation had a very wide range and differed from one population to another. Some traits (e.g. leaf width/leaf length ratio) were consistently less variable while others (e.g. leaf area and petiole length) were more plastic. All traits had significant genetic variance in all populations. Intra-class correlation coefficients differed for most of the traits and each population presented a different range of values. Most of the leaf traits were intercorrelated in all the populations studied, although some populations were integrated more tightly for some traits. Populations of A. serrata are differentiated in phenotypic means but they display a mosaic of traits with slight morphological differences in each locality (i.e. a quantitative genetic variation). Some traits can be correlated to the habitats that they occupy but for some of them it is difficult to assign an actual adaptive value. 相似文献
5.
Leaf shape linked to photosynthetic rates and temperature optima in South African <Emphasis Type="Italic">Pelargonium</Emphasis> species 总被引:1,自引:0,他引:1
The thermal response of gas exchange varies among plant species and with growth conditions. Plants from hot dry climates generally
reach maximal photosynthetic rates at higher temperatures than species from temperate climates. Likewise, species in these
environments are predicted to have small leaves with more-dissected shapes. We compared eight species of Pelargonium (Geraniaceae) selected as phylogenetically independent contrasts on leaf shape to determine whether: (1) the species showed
plasticity in thermal response of gas exchange when grown under different water and temperature regimes, (2) there were differences
among more- and less-dissected leafed species in trait means or plasticity, and (3) whether climatic variables were correlated
with the responses. We found that a higher growth temperature led to higher optimal photosynthetic temperatures, at a cost
to photosynthetic capacity. Optimal temperatures for photosynthesis were greater than the highest growth temperature regime.
Stomatal conductance responded to growth water regime but not growth temperature, whereas transpiration increased and water
use efficiency (WUE) decreased at the higher growth temperature. Strikingly, species with more-dissected leaves had higher
rates of carbon gain and water loss for a given growth condition than those with less-dissected leaves. Species from lower
latitudes and lower rainfall tended to have higher photosynthetic maxima and conductance, but leaf dissection did not correlate
with climatic variables. Our results suggest that the combination of dissected leaves, higher photosynthetic rates, and relatively
low WUE may have evolved as a strategy to optimize water delivery and carbon gain during short-lived periods of high soil
moisture. Higher thermal optima, in conjunction with leaf dissection, may reflect selection pressure to protect photosynthetic
machinery against excessive leaf temperatures when stomata close in response to water stress. 相似文献
6.
Morphological Variation in Populations of Ranunculus repens from the Temporary Limestone Lakes (Turloughs) in the West of Ireland 总被引:2,自引:0,他引:2
An unusual form of Ranunculus repens L. occurs in turlough basins(temporary lakes) in the West of Ireland. It is characterizedby more highly-dissected and glabrous leaves than the more typicalbroad-leaved form. Leaf dissection of both forms was quantifiedusing seed-derived plants which were cultivated in standardconditions. Leaves of both forms showed heteroblastic developmentand became increasingly dissected with each successively producedleaf until the adult leaf shape was attained around leaf 8.The dissection index of adult leaves was genetically based andhad a high heritability. Changes in leaf dissection were recordedacross a relatively deep, undulating turlough basin. The mostdissected leaf form was found deep within the basin among ahighly specialized species-poor community which was subjectedto the most prolonged period of inundation. An intermediate-leavedform occurred higher up the sides of the basin in a damp grasslandcommunity, where the period of inundation was more transient.A broad-leaved form occurred around the upper fringes of thebasin among a dry pastureland community. The intermediate-leavedform may have resulted from gene flow between the broad- anddissected-leaved populations, or may have evolved a distinctleaf shape adapted to the prevailing conditions at that pointwithin the basin. Copyright 2001 Annals of Botany Company Ranunculus repens L., turloughs, leaf shape, heritability, ontogeny, population biology 相似文献
7.
Stefan Andersson 《Plant Systematics and Evolution》1991,178(3-4):247-258
Canonical variate analysis of plants raised in a uniform environment was used to study the pattern of geographical variation in leaf shape ofCrepis tectorum (Asteraceae). The diversity in leaf shape was much greater among populations confined to areas with exposed bedrock in the Baltic region than among weed populations scattered throughout Europe and Canada. A Ward's clustering linked outcrop populations from the archipelago of SW. Finland and the islands of Öland (Sweden) and Saaremaa (Estonia) due to the deeply lobed leaves characterizing these populations, while outcrop populations along the coast of E. Sweden were grouped due to their weakly lobed, narrow and dentate leaves. Most of the weed populations were grouped together but there was no tendency for the variation in this group to be related to habitat or geographical location. A mosaic of variation reflected in sharp (random) differentiation among local populations was superimposed on the large-scale ecogeographical pattern.—Crossing data indicated that most of the variation in degree of leaf dissection is governed by one major gene with deeply lobed leaves dominant over weakly lobed leaves. I suggest that the simple pattern of inheritance may have favoured rapid evolutionary changes in leaf shape, particularly in the Baltic area which emerged relatively late from the sea. Genetic correlations may have constrained the pattern of variation at higher taxonomic levels, since some of the trait associations detected in a segregating F2 generation were also found at the among-population level. 相似文献
8.
Dana L. Royer 《PloS one》2012,7(11)
The degree of leaf dissection and the presence of leaf teeth, along with tooth size and abundance, inversely correlate with mean annual temperature (MAT) across many plant communities. These relationships form the core of several methods for reconstructing MAT from fossils, yet the direct selection of temperature on tooth morphology has not been demonstrated experimentally. It is also not known if atmospheric CO2 concentration affects leaf shape, limiting confidence in ancient climate reconstructions because CO2 has varied widely on geologic timescales. Here I report the results of growing Acer rubrum (red maple) in growth cabinets at contrasting temperature and CO2 conditions. The CO2 treatment imparted no significant differences in leaf size and shape, while plants grown at cooler temperatures tended to have more teeth and more highly dissected leaves. These results provide direct evidence for the selection of temperature on leaf shape in one species, and support a key link in many leaf-climate methods. More broadly, these results increase confidence for using leaf shape in fossils to reconstruct paleoclimate. 相似文献
9.
Water hyacinth leaves in natural populations vary from being long and thin-petioled to being short with inflated petioles. A variety of factors has been used experimentally to alter water hyacinth leaf shape, but what controls the development of leaf morphology in the field has not been established. We measured photosynthetic photon flux density (PPFD) and spectral distribution of radiation in a natural water hyacinth population. PPFD in the center of the water hyacinth mat was reduced to 2.7% of full sunlight, and the red to far red (R:FR) ratio was reduced to 0.28. When shoot tips of plants were exposed to artificial light environments, only plants in the treatment with a R:FR ratio comparable to that in the natural population produced leaves with long, thin petioles. Shoot tips in full sun or covered with clear plastic bags or bags that reduced light quantity without greatly altering light quality produced shorter leaves with inflated petioles. We hypothesize that the altered light quality inside a mat is a major environmental control of water hyacinth leaf morphology. 相似文献
10.
In the present study, the variation patterns of leaf shape in different populations of individual Semiliquidambar cathayensis plants were analyzed to investigate the relationship among leaf shape variation, photosynthetic properties, and active compounds to understand the genetic characteristics of S. cathayensis and screen elite germplasms. The leaf shape of 18 offspring from three naturalS. cathayensis populations was analyzed to investigate the level of diversity and variation patterns of leaf shape. Furthermore, photosynthetic pigment content, physiological parameters of photosynthesis, and the active compounds in leaves of different shapes were determined. Statistical analysis showed that the leaf shape variation in S. cathayensis indicated a high level of genetic diversity among and within the populations. Cluster analysis showed that the three natural populations formed two clusters, one whose offspring was dominated by entire leaves and another characterized by palmately trifoliate leaves. The differences in photosynthetic characteristics and active compounds of leaves of three different shapes were comprehensively evaluated using principal component analysis. Two principal components with a cumulative contribution rate of 92.768% were extracted, of which the highest comprehensive score was for asymmetrically lobed leaves. The leaf shape in different S. cathayensis germplasms exhibited distinct patterns, and there were some correlations between the photosynthetic properties and active compounds in leaves of different shapes. Thus, the leaf shape can be used to predict active compound content, and in turn, select varieties based on that purpose; it also provides a simple and effective method to classify S. cathayensis germplasms. 相似文献
11.
Summary Selected morphological features were measured in five populations of the giant rosette plant Espeletia schultzii occurring along an elevation gradient from 2600 to 4200 m in the Venezuelan Andes. Pith volume per amount of leaf area increases with elevation resulting in significantly larger water storage capacity at higher elevations. Thickness of leaf pubescence and, therefore, leaf boundary layer resistance, also increases with elevation resulting in both potentially higher leaf temperatures relative to air temperature and higher leaf to air vapor pressure gradients. The net effect on transpiration rate would depend on ratios of stomatal to boundary layer resistance and leaf energy balance. At higher elevations the central rosette leaves are more vertically oriented and the leaf bases show a pronounced curvature as the intersection with the main axis is approached. This gives these rosettes a distinctly paraboloid appearance and probably enhances capture and retention of incident long and shortwave radiation by the apical bud and expanding leaves. Features which result in enhanced water storage capacity and higher plant temperatures relative to air temperature without greatly increasing water loss are adaptive in high altitude paramo habitats where water availability and growth are limited by year round low temperatures (mean 2–3° C). 相似文献
12.
Ansari , A. Q., and W. E. Loomis . (Iowa State University, Ames.) Leaf temperatures. Amer. Jour. Bot. 46(10): 713–717. Illus. 1959.—Leaf temperatures were measured with a thermocouple and potentiometer. Readings were taken on leaves of varying thickness, under varying environmental and plant conditions, and during alternating heating and cooling cycles in sun and shade. Leaves tended to assume air temperature. Sunshine heated thin leaves 6–10°C. above the air in about 1 min. Very thick leaves were heated 20°C. above air in 20–30 min. Cooling in still air in shade was at the same rate as heating in sunshine, and the product of this rate times leaf mass in g./cm.2 was constant for all leaves tested. Wind at 5 m.p.h. lowered leaf temperature in the sun about half way to air temperature. This cooling effect can result in a reduction of transpiration by wind. Transpiration had a minor effect on leaf temperature. Wilted leaves showed nearly the same temperature response as turgid ones. Dried leaves heated less and cooled faster in shade than transpiring leaves. Vaselined leaves were 1–3°C. warmer than transpiring leaves but showed similar heating and cooling curves. 相似文献
13.
McLellan T 《American journal of botany》2005,92(10):1616-1623
Structural features of leaves, including size, shape, and surfaces, vary greatly throughout the plant kingdom. In both functional and phylogenetic analyses of leaves, the various morphological aspects are often considered independently of each other, although it is likely that many combinations of features do not occur at random due to either functional constraint or genetic correlation. The distribution of variation in leaf morphology in the highly variable Begonia dregei species complex was examined in natural populations and in F(2) offspring from a cross between plants from two populations. Leaf shape was quantified using several morphometric measures, and trichomes on leaves were counted and measured. Correlations between leaf shape and the numbers and size of trichomes were examined. There were significant correlations between the shapes of leaves and the presence, number, and size of trichomes among populations and in hybrid plants. Deeply incised leaves had larger numbers of longer trichomes at the sinuses. Higher numbers of trichomes on upper leaf surfaces occurred together with trichomes at the petiole and on the abaxial surface. The potential for independent evolution of leaf shape and trichomes in this group is limited. Hypotheses to explain the correlated development of leaf shape and trichomes are discussed. 相似文献
14.
Leaves of seed plants can be described as simple, where the leaf blade is entire, or dissected, where the blade is divided into distinct leaflets. Both simple and dissected leaves are initiated at the flanks of a pluripotent structure termed the shoot apical meristem (SAM). In simple-leafed species, expression of class I KNOTTED1-like homeobox (KNOX) proteins is confined to the meristem while in many dissected leaf plants, including tomato, KNOX expression persists in leaf primordia. Elevation of KNOX expression in tomato leaves can result in increased leaflet number, indicating that tight regulation of KNOX expression may help define the degree of leaf dissection in this species. To test this hypothesis and understand the mechanisms controlling leaf dissection in tomato, we studied the clausa (clau) and tripinnate (tp) mutants both of which condition increased leaflet number phenotypes. We show that TRIPINNATE and CLAUSA act together, to restrict the expression level and domain of the KNOX genes Tkn1 and LeT6/Tkn2 during tomato leaf development. Because loss of CLAU or TP activity results in increased KNOX expression predominantly on the adaxial (upper) leaf domain, our observations indicate that CLAU and TP may participate in a domain-specific KNOX repressive system that delimits the ability of the tomato leaf to generate leaflets. 相似文献
15.
16.
Geographic variation and plasticity of leaf shape and size in Begonia dregei and B. homonyma (Begoniaceae) 总被引:1,自引:0,他引:1
TRACY McLELLAN FLS 《Botanical journal of the Linnean Society. Linnean Society of London》2000,132(1):79-95
The distinction between Begonia dregei and B. homonyma has hitherto been based on differences in the shape and size of leaves. A large sample of field-collected leaves has been examined using quantitative methods to test the validity of this distinction. Comparisons of leaf shape, with and without the inclusion of size-related variables, revealed three groups with a small amount of overlap, two of which correspond to B. dregei and one to B. homonyma. Effects of environmental conditions on leaf shape and size were examined in plants from four populations grown at two light intensities and compared with field collections. Leaf size varied little with environment, while margin roughness varied with the different conditions and there was variation among populations in the magnitude and direction of responses. These results show that leaf shape and size can be used as valid discriminators of groups within this taxon. Resolution of the taxonomy of this group will require consideration of heterogeneity within each of the three groups based on leaf shape and size. 相似文献
17.
Population differentiation in Crepis tectorum (Asteraceae): patterns of correlation among characters
STEFAN ANDERSSON 《Biological journal of the Linnean Society. Linnean Society of London》1993,49(2):185-194
This study examines the relationship among traits distinguishing populations of C. tectorum and the extent to which existing trait associations reflect underlying (genetic) tradeoffs. Highly consistent trait associations were found in a comparison of 52 populations representing the western part of the geographical range of the species. In addition to a tight integration of traits reflecting plant stature and inflorescence development, there were consistent links between vegetative and reproductive traits; populations characterized by individuals with large leaves and tall stems with terminal branches usually had larger heads, flowers and fruits (achenes) than those whose individuals had small leaves and a short stem branched from the base. There was a weak negative relationship between the extent of leaf dissection and plant stature; short and compact plants had more deeply lobed leaves than tall plants with terminal branches. Few of these associations were present among families representing a single population of C. tectorum , but there was remarkable similarity between the correlations at the between-population level and those obtained in two segregating F2 progenies of crosses between contrasting populations. Hence, provided that the F2 correlations have a strong genetic basis, it appears that the course of population divergence has been constrained by the underlying correlation structure, although some trait associations may also be a result of selection operating in a correlated fashion on functionally related traits, perhaps leading to linkage disequilibrium of parental traits in the first segregating generation of a cross between ecologically differentiated populations. 相似文献
18.
植物叶片对环境变化十分敏感,能反映植物适应环境所形成的生存策略。为揭示高寒植物叶片性状对海拔高度变化的响应,对位于青藏高原东北部的冷龙岭3400—4200 m之间5个不同海拔高度的矮火绒草(Leontopodium nanum)叶片进行取样,采用常规石蜡制片技术和显微观察方法测定叶片外部形态、表皮气孔特征和解剖结构,探讨其叶片性状随海拔的变化,结果表明:(1)随海拔高度升高,叶面积呈减小的趋势,而比叶重和叶干物质含量增加;(2)叶片下表皮气孔密度随海拔升高呈先增加后下降的趋势,且气孔密度、气孔器面积、长度、宽度和潜在气孔导度指数等气孔特征之间存在显著相关性;(3)叶厚、栅栏组织和海绵组织厚度随海拔升高呈显著增厚的趋势;(4)叶片解剖结构可塑性和相关性分析显示,上、下角质层厚度的可塑性指数最大,而部分解剖结构指标间存在极显著的相关性。研究表明,矮火绒草为适应沿海拔上升温度降低的环境,主要采取叶片变小、变厚的对策,使植物趋于保温、保水和抗机械损伤的方向发展,并将资源最大化地投入到自身生长发育中。 相似文献
19.
科学家早已注意到,具有长叶寿命的植物通常生长于营养和(或)水分较为缺乏的环境,而具短叶寿命的植物一般生长在具有较高的营养可利用性地带。国外大量的实验研究结果表明,单位重量的叶氮含量(Nmass)与叶的最大光合速率存在密切正相关,而比叶面积(单位干重量的叶面积)与植物生产单位叶面积的物质成本呈负相关,二者又随叶寿命的增加而降低,这种相互关系几乎在所有植物种群和群落中都普遍存在,反映了植物对环境适应的趋同进化特征,是进一步理解生态系统行为特征的基础。松属(Pinus)及云杉(Picea)、冷杉(Abies)等常绿针叶树种的叶寿命一般随海拔的升高而增大,其相关叶性状也普遍存在明显的垂直分布格局:随着海拔升高,单位面积的叶氮含量(Narea)及最大光合速率增加,而比叶面积则减少。一般认为,长的叶寿命是对高寒及养分、水分贫乏等胁迫环境的适应,而短的叶寿命和(或)落叶性被认为是植物为了快速生长以及对干旱或寒冬等季节性胁迫环境的适应结果。根据成本-效益分析理论,在特定环境条件下叶寿命大小取决于形成并维护单位叶面积所需要的物质消耗与叶片碳收获的平衡,与常绿/落叶森林植被纬向/垂直地带性分布存在一种内在联系机理。因此,叶寿命及其相关叶性状成为将叶片水平上的生理生态实验数据扩展到整个群落冠层乃至生物地理群区的关键因子。加强叶寿命及其相关叶性状的格局分析研究,可为现有的区域生物地球化学循环模型与植被地理模型的连接(即区域植被动态模型)提供科学依据,这将有助于从机理上解释区域植被对全球变化的适应与响应机制。但是,以往植物生理生态研究大多注重于个体叶片水平的测定,仍不清楚如何实现这些叶性状在不同尺度间的转换,尤其是从叶片水平上升至整个群落冠层。国际上至今仍缺乏在生态系统水平上的大量野外观测数据来定量描述这些叶性状与群落特征、气候因子的数量关系;国内相关研究基本尚属空白。 相似文献
20.
This study assessed intrinsic differences in tissue quality and growth rate among populations of Metrosideros polymorpha native to sites with a range of soil fertilities. We collected seedlings from three Hawaiian mesic forests that were either phosphorus-limited, nitrogen-limited, or relatively fertile. These individuals were grown in a common garden under a factorial high/low, N/P fertilization regime for 1.5 years and then harvested to determine genetic divergence; aboveground growth rate; and lignin, N, and P concentrations in leaves and roots. Allozyme analyses indicated that the three groups had genetically diverged to some degree (genetic distance = 0.036-0.053 among populations). Relative growth rate did not differ significantly among the populations. Senescent leaves from the fertile-site population had the highest N concentrations (due to low N resorption) and had lower lignin concentrations than plants from the N-limited site. Across treatments, P concentrations in senescent leaves were highest in plants from the fertile and P-limited site. Root tissue quality did not generally differ significantly among populations. Since decomposition rate of senescent leaves in this system is related positively to N concentration and negatively to lignin concentration, senescent leaves from the fertile-site population may have a genetic tendency toward faster decay than the others. The intrinsic qualities of the three populations may provide positive feedbacks on nutrient cycling at each site-nutrient availability may be raised to some degree at the fertile site, and reduced at the N- or P-limited sites. Our results suggest that even a small degree of genetic differentiation among groups can influence traits related to nutrient cycling. 相似文献