浙江天童常绿植物当年生与往年生叶片性状的变异与关联

植物叶片性状随叶龄的变化是植物生活史策略的体现, 反映了植物叶片的物质投资和分配方式。该研究通过在个体和物种2个水平, 比较浙江天童1 hm ²样地内常绿阔叶树种的平均叶面积(MLA)、比叶面积(SLA)和叶片干物质含量(LDMC)在当年生和往年生叶片间的差异和关联, 探究叶片物质分配策略在异龄叶间的变化, 并分析叶龄对植物叶片性状, 特别是叶片面积建成消耗的影响。结果显示: 1)在个体和物种水平上, MLA变异系数最大(个体: 79.5%; 物种: 66.5%), SLA次之(个体: 28.1%; 物种: 24.7%), LDMC较低(个体: 17.0%, 物种: 14.1%); 当年生叶片MLA、LDMC和SLA的变异系数均高于往年生叶片; 2)往年生叶MLA显著大于当年生叶(t = -38.53, p < 0.001), 往年生叶SLA显著小于当年生叶(t = 45.30, p < 0.001), 往年生叶LDMC显著大于当年生叶(t = -9.71, p < 0.001); 3)在个体水平, 当年生叶片MLA、SLA和LDMC值分别解释了往年生叶片MLA、SLA和LDMC变异的86%、48%和41%; 在物种水平, 当年生叶片MLA、SLA和LDMC值分别解释了往年生叶片MLA、SLA和LDMC变异的97%、83%和85%; 4) SLA在异龄叶间的变化表明, 与往年生叶片相比, 投资相同干物质, 当年生叶片可形成较大的叶面积, 其叶片面积建成消耗较小。研究认为, 植物叶性状在异龄叶间具有较大的变异性和关联性, 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。     

Relationships between sclerophylly,leaf biomechanical properties and leaf anatomy in some Australian heath and forest species

ABSTRACT

A previous study of 19 south-east Australian heath and forest species with a range of leaf textures showed that they varied considerably in leaf biomechanical properties. By using an index of sclerophylly derived from botanists' rankings (botanists' sclerophylly index, BSI) we determined that leaves considered by botanists to be sclerophyllous generally had both high strength and work to fracture (particularly in punching and tearing tests), both at the level of leaf and per unit leaf thickness. In the current study we have shown that leaves from the same species also varied considerably in leaf specific mass (46–251 g m^-2), neutral detergent fibre concentration (20–59% on a dry weight basis) and in leaf anatomy. Multiple regression indicated a very strong correlation between BSI and the first two components of a principal components analysis (PCA) of leaf anatomy (R ² = 0.91). In addition, there was strong correlation between the first component of a PCA of the mechanical properties (correlated with BSI) and the two axes derived from anatomical characteristics (R ² = 0.66). The anatomical properties contributing most to the significant component axes were thickness of palisade mesophyll and upper cuticle (axis 1) and percentage fibre (neutral detergent fibre) and lower epidermis thickness (axis 2). However, whether these relationships are causal, or reflect correlations with characteristics not measured in this study, such as vascularization and sclerification, is not clear. At a finer scale, however, there is evidence that there are various ways to be sclerophyllous, both in terms of anatomical and mechanical properties. This is illustrated by comparison of two of the sclerophyllous species, Eucalyptus baxteri and Banksia marginata.     

Leaf traits indicate survival strategies among 42 dominant plant species in a dry, sandy habitat, China

The objective of this paper was to assess the congruency of leaf traits and soil characteristics and to analyze the survival strategies of different plant functional types in response to drought and nutrient-poor environ-ments in the southeastern Ke'erqin Sandy Lands in China. Six leaf traits-leaf thickness (TH), density (DN), specific leaf area (SLA), leaf dry weight to fresh weight ratio (DW/ FW), leaf N concentration (Nmass), and N resorption efficiency (NREmass)-of 42 plant species were investi-gated at four sites. The correlations between leaf traits and soil characteristics-organic C (OC), total N (TN), total P (TP), and soil moisture (SM)-were examined. We found that the six leaf traits across all the 42 species showed large variations and that DW/FW was negatively correlated with OC, TN, TP, and SM (P<0.05), while other leaf traits showed no significant correlations with soil characteristics. To find the dissimilarity to accommodate environment, a hierarchical agglomerative clustering analysis was made of all the species. All the species clustered into three groups except the Scutellaria baicalensis. Species of group Ⅲ might be most tolerant of an arid environment, and species of group Ⅱ might avoid nutrient stress in the nutrient-poor environment, while group Ⅰ was somewhat intermediate. Therefore, species from the different groups may be selected for use in vegetation restoration of different sites based on soil moisture and nutrient conditions.     

植物叶片形态的生态功能、地理分布与成因

叶片是植物与环境进行水气交换的重要场所, 形态多变。叶片形态可直接影响植物的生理生化过程, 反映植物的资源获取策略。该文以叶片大小、叶形、叶缘特征(有无叶齿)和叶型(单、复叶)等形态性状为例, 总结了当前叶片形态的研究进展, 分析了叶形态性状的生态功能, 综述叶片形态的地理分布, 探讨叶片形态性状变化的驱动因素及其对生态系统功能的影响。现有研究主要聚焦于局域尺度的特定类群, 关注叶大小、叶缘具齿性以及叶型的地理分布与生态成因, 发现叶片的形态发育受基因调控, 叶形态性状与其他性状相互权衡, 其空间变异受气温和降水量共同驱动。以叶大小为代表的叶片形态性状影响水分和养分循环, 能够反映气候变化下的群落响应, 也可用于预测生态系统初级生产力。今后应结合新方法获得覆盖度高且区域无偏的数据, 探索叶形态在长时间尺度上的适应性进化, 研究叶形态特征及其对生态系统功能影响的尺度推绎。该文有助于从叶片的角度认识植物对环境变化的响应, 以性状为桥梁将个体适合度、群落动态与生态系统功能联系起来, 能够加深对植物群落生态学和功能生物地理学等相关领域研究进展的了解。     

High-Temperature Preconditioning and Thermal Shock Imposition Affects Water Relations,Gas Exchange and Root Hydraulic Conductivity in Tomato

Potted tomato plants (Lycopersicon esculentum Mill. cv. Amalia) were submitted to three different treatments: control (C) plants were maintained at day/night temperature of 25/18 °C; preconditioned plants (PS) were submitted to two consecutive periods of 4 d each, of 30/23 and 35/28 °C before being exposed to a heat stress (40/33 °C lasting 4 d) and non-preconditioned (S) plants were maintained in the same conditions as the C plants and exposed to the heat stress. The inhibition of plant growth was observed only in PS plants. Heat stress decreased chlorophyll content, net photosynthetic rate and stomatal conductance in both PS and S plants. However, PS plants showed good osmotic adjustment, which enabled them to maintain leaf pressure potential higher than in S plants. Furthermore, at the end of the recovery period PS plants had higher pressure potential and stomatal conductance than in S plants. This revised version was published online in July 2006 with corrections to the Cover Date.     

Salinity, growth and root respiration in the grey mangrove, Avicennia marina

Relationships between growth parameters and root respiration under various conditions of salinity were investigated in seedlings of the grey mangrove Avicennia marina (Forsk.) Vierh. Growth, root/shoot ratios, leaf succulence and osmotic potential of leaves were measured for seedlings grown for 6–8 weeks in 100, 50, 25 and 0% seawater. Oxygen uptake of root segments, from distal to proximal ends of roots, was measured for all treatments. Total growth was maximal in 25% seawater, highest leaf succulence was obtained in 50% seawater, and highest leaf osmotic potential in 100% seawater. Oxygen uptake in distal root segments, as measured both by Clark oxygen electrode and Warburg manometry, showed a stimulation in the presence of salt that closely paralleled growth stimulation. The rates of respiration were highest in 25% seawater. The oxygen uptake was not stimulated by salt per se, since concentrations higher than 25% were associated with a decline in rate of oxygen uptake from the maximum. Values for the respiratory quotient approximated to one in all treatments. Avicennia marina has been reported to exclude from its roots about 90% of the salt in the surrounding medium. It might have been expected that increased concentrations of salt in the growth medium would be associated with a standard salt respiration response in the roots; however, this was not obtained.     

Effects of leaf age,elevation and light conditions on photosynthesis and leaf traits in saplings of two evergreen conifers,Abies veitchii and A. mariesii

亚高山的针叶树物种分布在广泛的海拔范围内,因此它们必须具备抵抗严酷自然条件(如高海拔和长期的黑暗)的能力。 在日本中部的亚高山地带,两种常绿的针叶树冷杉(Abies veitchii)和马尾冷杉(Abies mariesii)分别在低海拔和高海拔地区占据优势。本研究的目的是探讨叶龄、海拔和光照条件对两个物种叶片形态和生理性状的影响。我们以两种针叶树的幼树为样本,分别在两种针叶树下部 (1600米)和上部(2300米)的林下层和冠层间隙中取样,并分析叶龄、海拔和光照条件对冷杉和马尾冷杉的光合作用和叶片性状的影响。研究结果表明,两种针叶树的光合作用和叶片性状对叶龄呈现相似的响应,但其对海拔和光照条件则表现出不同的响应。冷杉最大光合速率与单位叶面积质量和非结构性碳水化合物浓度呈负相关。两种树木的单位叶面积质量在高海拔处均增加,而非结构性碳水化合物浓度仅在冷杉中增加。因此,冷杉的最大光合速率在高海拔时降低。此外,两个物种的最大光合速率均与氮浓度呈正相关。在林下层,叶片氮浓度在冷杉中下降,而在马尾冷杉中上升。在林下条件下,只有马尾冷杉的单位叶面积质量下降、叶绿素-氮比增加,表明在黑暗条件下,马尾冷杉比冷杉有更高的捕光效率。本研究表明,与冷杉相比,马尾冷杉的光合和叶片特性具有更强的耐阴性,光合速率受海拔的影响较小,从而使马尾冷杉在林下植被中生存,并在高海拔地区占据优势。     

Leaf traits and their interrelationship of 23 plant species in southeast of Keerqin Sandy Lands,China

Six leaf traits,i.e.,fresh mass (FM),dry mass (DM),leaf dry matter content (DMC),area (AR),specific leaf area (SLA) and thickness (TH) from 23 plant species in the southeastern Keerqin Sandy Lands,China were measured.The results show that leaf traits of herbs were more diversified than those of shrubs and trees and aver-age SLA tended towards a decreasing trend from herbs to shrubs to trees.On the contrary,DMC and DM show an upward trend from herbs to shrubs to trees.No apparent difference was found in TH.Except for DM and TH,there were significant variations in SLA and DMC among three different growth forms.Moreover,a significant correla-tion was found between SLA and DMC.It is concluded that SLA and DMC could be used to predict species posi-tion along a resource use gradient.     

Leaf traits and their interrelationship of 23 plant species in southeast of Keerqin Sandy Lands, China

Six leaf traits, i.e., fresh mass (FM), dry mass (DM), leaf dry matter content (DMC), area (AR), specific leaf area (SLA) and thickness (TH) from 23 plant species in the southeastern Keerqin Sandy Lands, China were measured. The results show that leaf traits of herbs were more diversified than those of shrubs and trees and average SLA tended towards a decreasing trend from herbs to shrubs to trees. On the contrary, DMC and DM show an upward trend from herbs to shrubs to trees. No apparent difference was found in TH. Except forDMand TH, there were significant variations in SLA and DMC among three different growth forms. Moreover, a significant correlation was found between SLA and DMC. It is concluded that SLA and DMC could be used to predict species position along a resource use gradient. __________ Translated from Chinese Journal of Ecology, 2006, 25: 921–925 [译自: 生态学杂志]     

Morphology and morphogenesis of ensiform leaves, syndesmy of shoots and an understanding of the thalloid plant body in species of Apinagia, Mourera and Marathrum (Podostemaceae)

The flattened, irregularly shaped and lobed or dissected leaves of Apinagia riedelii , A. latifolia , A. goejei , Mourera aspera and Marathrum utile (subfamily Podostemoideae) are ensiform in structure. After the typical bifacial inception, further growth of leaves proceeds in the midrib area, i.e. in the median plane of the leaf. The lower leaf zone is characterized by a sheath that orientates 'at the side of the blade', i.e. at the adaxial edge of the sword-like leaf. The ensiform blades are lobed, incised or pinnately dissected with the tips terminated in elongated threads or thin filaments. Leaves of Apinagia riedelii resemble pinnately dissected compound leaves. The dissected structure represents a secondary superimposition of the ensiform shape and a parallel development to compound leaves. It is interpreted as an adaptation to the rapid current, established in the floating shoots of these aquatic plants. The basal portions of main shoots and successive branches are fused due to a retarded separation. Fusion of this kind has been termed a syndesmy. The fused region of shoots is superseded by the fusion of the lower leaf zones of (distichously positioned) adjacent leaves, occurring at their margins. The fused leaf bases form a cavity for the terminal flower bud of each shoot and cover it in the form of a hood. The flower buds are hidden from external view. The meristematic growing zones are thus protected and enclosed within the syndesmic plant body which, in this way, attains the 'thalloid' appearance especially developed in Apinagia goejei and A. latifolia but also present in the other species. The results of this study enable an understanding of the particular appearance of these Podostemoideae as modifications of the typical structures according to the 'principle of variable proportions'.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 147 , 47–71.     

祁连山高寒草地甘肃臭草叶性状与坡向间的关系北大核心CSCD

植物功能性状可反映植物对环境的适应。在祁连山高寒退化草地,利用Arc GIS建立研究区域的数字高程模型,提取坡向数据,采用标准化主轴估计方法(standardized major axis estimation,SMA),研究了不同坡向甘肃臭草(Melica przewalskyi)叶性状间的关系。结果表明:1)甘肃臭草叶面积和叶体积在北坡最大,东坡、西坡、南坡逐渐减小,叶干质量无显著变化;2)叶面积与叶干质量在北坡、东坡和西坡呈等速生长关系,在南坡呈异速生长关系,且叶干质量的增长速度大于叶面积的增长速度;3)叶体积与叶干质量在4个坡向上呈异速生长关系,且叶干质量的增长速度均小于叶体积的增长速度。甘肃臭草叶性状关系随坡向的变化反映了该物种在异质生境中具有较强的叶片形态可塑性,从而有利于其适应和占据高寒退化生境。     

祁连山高寒草地甘肃臭草叶性状与坡向间的关系

植物功能性状可反映植物对环境的适应。在祁连山高寒退化草地, 利用ArcGIS建立研究区域的数字高程模型, 提取坡向数据, 采用标准化主轴估计方法(standardized major axis estimation, SMA), 研究了不同坡向甘肃臭草(Melica przewalskyi)叶性状间的关系。结果表明: 1)甘肃臭草叶面积和叶体积在北坡最大, 东坡、西坡、南坡逐渐减小, 叶干质量无显著变化; 2)叶面积与叶干质量在北坡、东坡和西坡呈等速生长关系, 在南坡呈异速生长关系, 且叶干质量的增长速度大于叶面积的增长速度; 3)叶体积与叶干质量在4个坡向上呈异速生长关系, 且叶干质量的增长速度均小于叶体积的增长速度。甘肃臭草叶性状关系随坡向的变化反映了该物种在异质生境中具有较强的叶片形态可塑性, 从而有利于其适应和占据高寒退化生境。     

Traits,neighbors, and species performance in prairie restoration

Questions: Are traits related to the performance of plant species in restoration? Are the relationships between traits and performance consistent across the functional groups of annual forbs, perennial forbs and grasses? Do the relationships between traits and performance depend on neighboring functional groups? Location: A former agricultural field, being restored to native upland prairie, in the Willamette Valley of western Oregon, USA. Methods: Twenty‐eight native species, representing three functional groups, were sown in seven different combinations. Eleven functional traits were measured from plants in the laboratory and in the field. Correlations between individual traits and performance variables were measured and regression techniques used to determine which sets of traits were most strongly related to performance. Results: Sets of traits explained up to 56% of variation in cover, and up to 48% of variation in establishment frequency. The relationships between traits and performance were influenced by functional group identity; the functional group identity of neighboring species also influenced species' cover and the relationships between traits and cover. Species' establishment rate in monoculture was the trait most strongly correlated to both establishment and cover in mixtures. In multi‐trait models, annual forb functional group identity was strongly related to establishment in mixtures, and height, leaf weight ratio at 7 d and seed mass were strongly related to cover. Conclusions: Multiple‐trait models should be a useful way of predicting the performance of species prior to sowing in restoration. The functional group identity of each species and the other species being sown may need to be taken into account when making predictions.     

Associations between leaf structure, orientation, and sunlight exposure in five Western Australian communities

Five plant communities in Western Australia, as well as selected desert and Rocky Mountain species of the western USA, were surveyed to evaluate associations among leaf structure, orientational properties, and the sunlight exposure and precipitation characteristic of each community. Selected leaf structural features have been associated previously with photosynthetic function and included shape, thickness, the ratio of thickness to width, stomatal distribution, leaf surface coloration, and the number and distribution of palisade cell layers. Decreases in annual precipitation (<4 to over 15 cm/yr) and increases in total daily sunlight (4.2 to 29.2 mol photons/m1) corresponded strongly to an increase in the percentage of species in a given community with more inclined (more inclined than +/- 45 degrees from horizontal) or thicker leaf mesophyll (>0.4 mm) leaves. Also, the percentage of species with a leaf thickness to width ratio >0.1, which were amphistomatous, or which had palisade cell layers beneath both leaf surfaces, increased from >20% in the highest rainfall and lowest sunlight community to >80% in the community with least rainfall but greatest sunlight exposure. Over 70% of the species in the most mesic, shaded community had lighter abaxial than adaxial leaf surfaces (leaf bicoloration). All of the above structural features were positively associated with a more inclined leaf orientation (r1 = 0.79), except for leaf bicoloration, which was negatively associated (r1 = 0.75). The ratio of adaxial to abaxial light was more strongly associated with leaf bicoloration (r1 = 0.83) and the presence of multiple adaxial and isobilateral palisade cell layers(r1 = 0.80) than with total incident sunlight on just the adaxial leaf surface (r1 = 0.69 and 0.73, respectively). These results provide field evidence that leaf orientation and structure may have evolved in concert to produce a photosynthetic symmetry in leaf structure in response to the amount of sunlight and other limiting factors of the community. This structural symmetry may serve fundamentally to regulate the distribution of both light and CO2 levels inside the leaf and, thus, increase photosynthetic CO2 uptake per unit leaf biomass.