中国假鹰爪属和皂帽花属植物叶的形态结构及其分类学意义

利用扫描电镜技术、叶片离析法和石蜡切片法研究了假鹰爪属Desmos 4种植物和皂帽花属Dasy-maschalon 3种植物叶片的形态结构。结果表明：假鹰爪属植物叶片近轴面表皮具大型球状含晶簇细胞和不含晶簇的表皮细胞两种类型,远轴面表皮细胞均具一较小的晶簇;叶肉组织明显分化为栅栏组织细胞和海绵组织细胞,油细胞分布于第2层的栅栏组织和海绵组织内,单位毫米叶宽油细胞数为4～6个;主脉维管组织被薄壁细胞分隔成束状。皂帽花属植物叶片近轴面表皮细胞形状相同,均具一晶簇,远轴面表皮细胞的晶簇和近轴面表皮细胞的晶簇相似;靠近上、下表皮的叶肉组织均分化为栅栏组织细胞,在两层栅栏组织细胞之间分化为一至几层海绵组织细胞,油细胞分布于海绵组织内,单位毫米叶宽油细胞数为2～3个;主脉维管组织形成连续的环状。由此可见两属叶的结构具有明显的差异,因而支持假鹰爪属和皂帽花属为两个独立属的观点。     

番荔枝科蚁花属和澄广花属叶的比较解剖学研究

利用扫描电镜技术,叶片离析方法和石蜡切片法对蚁花属1种和澄广花属9种植物叶的形态结构进行比较研究。结果表明,两属植物有许多相似之处,但又有以下一些显著不同;蚁花属植物叶表皮细胞均具一晶族,叶肉组织中具1-2层栅栏组织细胞,油细胞均匀分布在栅栏组织和海绵组织中,栅栏组织在主脉处不连续,而澄广花属植物叶的表皮细胞内具一单斜晶,叶肉组织中具1层栅栏组织细胞,油细胞仅分布在海绵组织中,栅栏组织在主脉处连续,结果为蚁花属和澄广花属的分类学处理提供了新证据。     

白蜡虫7种寄主植物叶片解剖结构与寄主选择性的关系

用石蜡切片法在显微镜下观察白蜡虫[Ericerus pela(Chavannes)]7种寄主植物叶的解剖结构。结果表明,寄主植物的叶脉、表皮、栅栏组织、海绵组织、维管束解剖结构及数量性状特征在属、种间存在显著差异。7种寄主植物中,华南小蜡(Ligustrum calleryanum Decne.)和白蜡树(Fraxinus chinensis Roxb.)表皮被毛,华南小蜡表皮毛浓密,白蜡树表皮毛稀疏,其它寄主植物表皮无毛;女贞树(Ligustrum lucidum Ait.)栅栏组织、海绵组织和叶脉的厚度最厚、维管束直径最大,其它寄主植物相对较小。因此,叶片表面光滑、叶脉发达、叶片肥厚是白蜡虫优良寄主植物的重要解剖学特征。7种寄主植物中脉和侧脉发达,近轴面凹陷,远轴面突起,肉脉包埋在叶肉中,推测叶脉突起和凹槽可能是白蜡虫固定位点选择的关键线索。     

暗罗属植物叶的比较解剖学研究

利用扫描电镜技术、叶片叶片离析方法和石蜡切片法对暗罗属12种植物叶和形态结构进行了比较研究。结果表明,叶表皮细胞形状、气孔器形态、表皮毛类型、表皮细胞中晶体类型、叶肉中油细胞分布位置、栅栏组织和海绵组织厚度的比值,以及主脉维管组织的结构特征等具有明显的种间差异。可以利用这些叶的解剖特征将暗罗属植物相互区别开来。     

Duabanga-like leaves from the Middle Eocene Princeton chert and comparative leaf histology of Lythraceae sensu lato

A permineralized lythraceous leaf type found in close association with fruits, stems, and roots of Decodon allenbyensis Cevallos-Ferriz et Stockey in the Middle Eocene Princeton chert of British Columbia, Canada, is described. Midribs have a prominent C-shaped midvein surrounded by sclerenchyma, with an adaxial epidermis of rectangular to rounded cells lacking enlarged mucilage cells. Leaves are dorsiventral, 180-270 μm thick at the lamina, with a double palisade layer. Abaxial epidermal cells have prominent papillae, and these epidermal cells can be infected by fungi, forming dark sterile stromata. Fossil leaves are similar to those of Myrtales and are compared to those of Lythraceae sensu lato. Although these leaves are thought to belong to the previously described Decodon allenbyensis found in the same chert layer, they lack the diagnostic features of extant Decodon leaves. Instead they share most anatomical similarities with Duabanga grandiflora Roxburgh ex DC Walpers (Lythraceae, subfamily Duabangoideae) including vascular tissues, palisade and spongy mesophyll, bundle fibers, and abaxial epidermal papillae. Duabanga grandiflora differs from the fossil in having mucilaginous cells and a consistently V-shaped abaxial midrib. Although anatomically similar to Duabanga, the fossil leaves are considered those of D. allenbyensis, based on association and the depositional environment prior to preservation. Recent phylogenetic analyses place Duabanga and Decodon in separate clades within Lythraceae, but relationships between these clades are not well supported, indicating that fossil leaves should provide useful anatomical characters for elucidating relationships within Lythraceae.     

Epidermal focussing and effects upon photosynthetic light-harvesting in leaves of Oxalis

Abstract. In Oxalis , epidermal cells on both the adaxial and abaxial surface of the leaf concentrated light within the leaf by a lens mechanism. Focal lengths of epidermal cells were estimated using two methods: they were calculated from radius of curvature measurements taken from individual epidermal cells, and were measured directly in agarose replicas of the leaf surface. In the three species of Oxalis examined, light that was incident upon the adaxial leaf surface was concentrated within the palisade, whereas light that was incident upon the abaxial leaf surface was concentrated within the spongy mesophyll. Using sensiometric analysis, theoretically maximal focal intesifications were measured in leaf replicas at the focal maximum and at intermediate positions corresponding to the mid-region of the palisade and spongy mesophyll tissues. Focal intensifications ranged from 2.2 to 10.4 times incident light at the focal maximum, and 1.3 to 4.5 in the palisade or spongy mesophyll layers. Elimination of epidermal focussing, by covering the leaf surface with a thin layer of mineral oil, strongly affected chlorophyll fluorescence induction curves resulting in a decrease of 10–40% in the initial (F₀) and variable fluorescence (F_v). These results are consistent with the interpretation that the chloroplasts were adapted to their light microenvironment within the leaf and that focussing by the epidermis channelled light to a population of chloroplasts that were adapted to high light.     

Leaf anatomical variation in Alchornea triplinervia (Spreng) Mull. Arg. (Euphorbiaceae) under distinct light and soil water regimes

Alchornea triplinervia (Spreng.) Müll. Arg. (Euphorbiaceae) is a tree which occurs in a broad range of habitats in Brazil. In the State of Rio de Janeiro, it occurs from montane forests to swamplands at sea level. A quantitative approach was used to examine the role of light and soil water regime on the variations found in anatomical traits of the palisade and spongy parenchyma, outer epidermal cell wall of the abaxial and adaxial surfaces, the percentage of sclerenchymatous area in relation to the total midrib area and the ratio of palisade to spongy parenchyma for five distinct ecological populations: M—late secondary montane forest (shaded, unflooded); M2—early secondary montane forest (semi-exposed, unflooded); SI—primary swamp forest (semi-exposed, flooded); S2—secondary swamp forest (exposed, flooded); and D—deforestation area (exposed, unflooded). Tukey tests were carried out for multiple comparisons, while one-way factor variance analysis was used to test for differences among ecological populations. A principal component analysis was used to order the populations as well as to find the higher variance component. These populations developed different response levels to the environmental factors studied, namely light and soil water regime. Light accounted for the variations found in palisade and spongy parenchyma while the combination of light and soil water determined the variations found regarding the outer epidermal cell wall of the abaxial surface, the percentage of sclerenchymatous area in relation to the total midrib area and the compaction of the spongy parenchyma. The separation of S1/M2 and S2/D populations into two groups was due to similar light regimes, which suggested that light was affecting the leaf anatomical variation of A. triplinervia more than the interaction of light and soil water regime.     

Micromorpho-Anatomical Examination of 2,4-D Phytotoxicity in Grapevine (Vitis vinifera L.) Leaves

The anatomical and micro-morphological alterations as induced by the auxinic herbicide, 2,4-D (2,4-dichlorophenoxy acetic acid) have not yet been elucidated for a commercially important fruit crop such as grapevine despite its super sensitivity to 2,4-D. Light and scanning electron microscopy techniques were employed to examine 2,4-D induced internal and external structural abnormalities in Merlot grapevines (Vitis vinifera L.). Healthy leaves were dorsiventrally flattened with well developed patterns of cellular structure and composition involving adaxial palisade parenchyma and abaxial spongy mesophyll. Dorsiventral variations in epidermal features involved large epidermal cells on the adaxial surface, and trichomes and stomata with turgid elliptical guard cells on the abaxial surface. The 2,4-D injured leaves were small and enated; the veins were fasciated with rugose bands of lamina existing between fasciated veins. The epidermal cells aggregated instead of being positioned coplanar to the epidermal plane. The adaxial elongated palisade parenchyma cells were transformed into an ovoid shape with intercellular spaces. An extensive development of replacement tissues took place on the abaxial surface wherein the stomata became roundish and were either raised or sunken with collapsed and cracked guard cells that developed abnormal outer stomatal ledges. These abnormalities are expected to severely perturb the vital functions of photosynthesis and transpiration ultimately leading to vine death attributable, at least in part, to the injured leaves.     

Photosynthetic and structural acclimation to light direction in vertical leaves of Silphium terebinthinaceum

The azimuth of vertical leaves of Silphium terebinthinaceum profoundly influenced total daily irradiance as well as the proportion of direct versus diffuse light incident on the adaxial and abaxial leaf surface. These differences caused structural and physiological adjustments in leaves that affected photosynthetic performance. Leaves with the adaxial surface facing East received equal daily integrated irradiance on each surface, and these leaves had similar photosynthetic rates when irradiated on either the adaxial or abaxial surface. The adaxial surface of East-facing leaves was also the only surface to receive more direct than diffuse irradiance and this was the only leaf side which had a clearly defined columnar palisade layer. A potential cost of constructing East-facing leaves with symmetrical photosynthetic capcity was a 25% higher specific leaf mass and increased leaf thickness in comparison to asymmetrical South-facing leaves. The adaxial surface of South-facing leaves received approximately three times more daily integrated irradiance than the abaxial surface. When measured at saturating CO₂ and irradiance, these leaves had 42% higher photosynthetic rates when irradiated on the adaxial surface than when irradiated on the abaxial surface. However, there was no difference in photosynthesis for these leaves when irradiated on either surface when measurements were made at ambient CO₂. Stomatal distribution (mean adaxial/abaxial stomatal density = 0.61) was unaffected by leaf orientation. Thus, the potential for high photosynthetic rates of adaxial palisade cells in South-facing leaves at ambient CO₂ concentrations may have been constrained by stomatal limitations to gas exchange. The distribution of soluble protein and chlorophyll within leaves suggests that palisade and spongy mesophyll cells acclimated to their local light environment. The protein/chlorophyll ratio was high in the palisade layers and decreased in the spongy mesophyll cells, presumably corresponding to the attentuation of light as it penetrates leaves. Unlike some species, the chlorophyll a/b ratio and the degree of thylakoid stacking was uniform throughout the thickness of the leaf. It appears that sun-shade acclimation among cell layers of Silphium terebinthinaceum leaves is accomplished without adjustment to the chlorophyll a/b ratio or to thylakoid membrane structure.     

Comparative leaf anatomy of Salix species and hybrids

Epidermal features, mesophyll differentiation and calcium oxalate characteristics of 19 species and 12 hybrids of Salix are described. The species and hybrids can be distinguished by the presence or absence of the following epidermal features: striated cuticle; stomata; covering trichomes; beaded anticlinal walls, and diosmin-like njstals. In or near marginal teeth, glandular trichomes are present in all cases. The leaf veins of all specimens examined have calcium oxalate prism sheaths and, with the exception of S. herbacea , cluster crystals in some cells of the mesophyll. Most sprcies studied in the subgenus Salix show: both adaxial and abaxial stomata; striated cuticle metopllyll of palisade cells, with little or no spongy mesophyll, but with a well-defined hypodermis, and absence of thick-walled, sinuous trichomes. Characteristic features of the subgenus Caprisalix are: abaxial stomata only; epidermal crystals; smooth cuticle; mesophyll diflerentiated into palisade cells and spongy mesophyll and without a hypodermis, and trichomes more numerous and varied than those of the subgenus Salix . Leaves of the two species of the subgenus Chaemelia examined and those of S. lapponum , have predominantly anomocytic stomata, whereas all the other leaves studied have predominantly paracytic stomata. The anatomical features described, in conjunction with the morphologiral characters, enable the species and hybrids of Salix studied to be autheenticated.     

Comparative studies on leaf structure and oil cells of the Magnoliaceae in China

The leaf structure and morphology, the structure and location of oil cells in leaves of 82 species and 1 subspecies in 10 genera of the Magnoliaceae were comparatively studied using tissue clearing, paraffin sectioning and thin sectioning. In leaves of Liriodendroideae, some of abaxial epidermal cells are papillose and the vascular tissue of the main vein appeared to be separated. However, papillose cells were not found and there were uniseriate, multicellular or unicellular hairs distributed on the epiderm, and the vascular tissue of the main vein appeared to be continuous in leaves of the Magnolioideae. Furthermore, in the Magnolioideae, the structure of leaves of Manglietia were different from that of Magnolia. These results support the separation of Magnolioideae and Liriodendroideae, and suggest that Manglietia and Magnolia be independent genera, which is consistent with Law’ s taxonomic scheme. Oil cells are one of marked features of the leaf anatomy of the Magnoliaceae, and they are mainly distributed in the palisade tissue in leaves of 47 species and in the spongy tissue in leaves of 5 species, and dispersed in the whole mesophyll in leaves of 31 species. The size and location of oil cells in leaves, combined with the thickness of leaves, the number of layers of the palisade tissue, the ratio of palisade tissue to spongy tissue in thickness, the hypo-derm, and the type of hairs may be used as the characteristics of genera and even species.     

中国木兰科植物的叶结构及其油细胞的比较解剖学研究

利用组织透明法、石蜡切片法及薄切片法对木兰科10属82种1亚种植物叶片的结构和油细胞的 分布密度、结构及其在叶肉中的分布进行了比较研究。鹅掌楸亚科和木兰亚科在叶结构上的主要区别是：鹅掌楸亚科两种植物叶的部分下表皮细胞乳突状,且整个细胞外壁只形成一个乳突,而在木兰亚科植物中有单列多细胞或单细胞的表皮毛,却未发现乳突;鹅掌楸亚科植物叶主脉维管组织环分隔呈束状,且其外包被的纤维也排列成束状,而木兰亚科的80种1亚种植物中,叶主脉维管组织连成轮状,其外面也由一圈连续的纤维环所包围。从而支持木兰科中木兰亚科和鹅掌楸亚科两个亚科的划分。并且,从叶主脉的演化趋势来看,鹅掌楸亚科较木兰亚科进化。另外,木莲属植物叶片的结构与木兰属具有明显差异,因而进一步证明木莲属是不同于木兰属的一个独立的属。油细胞是木兰科植物叶片解剖的显著特征,在叶肉中的分布可划分为3种类型：(A)主要分布于栅栏组织;(B)主要分布于海绵组织;(c)均匀散布于整个叶肉中。油细胞的大小及其在叶中的分布与叶厚、栅栏组织层数、栅栏组织与海绵组织厚度间的比值以及下皮层的有无、表皮毛的类型、叶脉的结构等特征相结合,可作为属、甚至种的鉴别特征。     

稀有植物香果树叶解剖结构的研究

通过石蜡切片法制片,光学显微镜观察,Motic显微摄像,研究了香果树（Emmenopterys henryi Oliv.）的叶形态解剖结构。结果表明,香果树叶为典型异面叶;表皮由一层紧密的形状不规则的表皮细胞组成,细胞外壁角质膜较薄;气孔类型为平列型,仅分布于下表皮;下表皮上零星分布着多细胞表皮毛;叶肉组织发达,栅栏组织由1~2层排列整齐的圆柱形细胞构成;海绵组织枝状分布,排列极为疏松,细胞间隙大;叶脉主脉发达;上述特征反映出植物结构与环境的统一性。     

鹤山重建植被的几种优势种叶解剖学研究

对南亚热带鹤山恢复植被5种优势种湿地松（Pinus elliottii）,马占相思（Acacia mangium）,大叶相思（Acacia auriculaeformis）,九节（Psychotria rubra）和南洋楹（Albizia falcata）进行了叶解剖学研究。结果显示,变化表现在表皮角质膜的厚度、细胞壁的厚度和形状,叶肉组织中海绵组织和栅栏组织的分化,内皮层维管束的构造等。为以后进一步探讨植被恢复过程中叶解剖结构的变化提供了实验基础。     

Compared Anatomy of Young Leaves of Prunus persica (L.) Batsch with Different Degrees of Susceptibility to Taphrina deformans (Berk.) Tul

Anatomical observations of leaves infected by Taphrina deformans were studied in tolerant peach trees (TPT) and in very susceptible (VSPT) ones. Leaves from the first sampling (2nd April) showed hyphae penetrating through the stomata or into the cuticle of the host tissue; anatomical structures of leaf sections were similar for both TPT and VSPT. The ultrastructure of the leaves of TPT showed seemingly normal mesophyll cells. In contrast, mesophyll cells of the VSPT showed important signs of degradation. Cells were organelle‐free and the middle lamella was expanded and invaded by hyphae of T. deformans. In some samples, the leaves of TPT showed deformed epidermal cells, loss of some spongy cells and increase of the intercellular spaces and division of the palisade cells. The pathogen proliferation in the leaves of the VSPT was considerably superior. In this case, stimulation of cell division occurred in the abaxial epidermis. Cells showed periclinal and oblique divisions, with an increased number of plasmodesmata; palisade or spongy cells were not differentiable. Leaves from TPT collected on 26th April showed hyphae with a non‐cylindrical section and with a squashed aspect. The hyphae were very evident in the intercellular spaces, showing abundant endoplasmic reticulum of rough type (RER) in the cytoplasm. On the other hand, epidermis of the leaves of the VSPT had numerous hyphae under the cuticle, which were growing in a thick pectin matrix. Leaves from TPT and VSPT collected on 6th May showed relevant differences. The leaves of TPT had a palisade mesophyll with fewer cells but with active chloroplasts. In contrast, the leaves from VSPT showed empty mesophyll cells, the cytoplasm was collapsed and the adaxial epidermis was covered with the fungus fructification. The observed anatomical and ultrastructural differences of leaves from TPT and VSPT confirm a different behaviour in plant‐host reaction at early stages of infection.     

Redifferentiation of leaflet tissues during midrib gall development in Copaifera langsdorffii (Fabaceae)

The tree Copaifera langsdorffii is a superhost for galling herbivores. This plant species has great morphogenetic potential, and responds differently to the stimuli of more than 20 gall-inducing insects. Among these, an undescribed species of Cecidomyiidae induces a midrib gall in which a radial cecidogenetic field is generated and the leaflet tissues redifferentiate. Our objectives were to assess the amplitude of this cecidogenetic field, in which the leaflet tissues were influenced by the feeding action of the cecidomyiid; how the final gall shape was generated; and if tissue redifferentiation conferred any adaptive value on the galling herbivore. Leaflet morphogenesis followed the pattern described in the literature for simple leaves, resulting in a mesophytic arrangement. Tissue redifferentiation due to gall formation revealed that in a midrib gall, abaxial epidermal cells divided to enlarge the gall; spongy parenchyma cells originated the storage tissue, secretory structures, and vascular bundles; palisade parenchyma cells became homogeneous; and adaxial epidermis originated the nutritive tissue. Cell elongation, a necessary step towards cell redifferentiation, is triggered by an increase in water transport to the gall site and vacuole pressure due to neoformed xylem bundles. The generation of the final shape of the midrib gall involved repetitive histological steps in response to the amplitude of the cecidogenetic field. The largest impact of the cecidomyiid feeding action occurred in gall tissues redifferentiated from protoderm and adaxial ground meristem, which provided advantages to the gall maker of the C. langsdorffii midrib gall in terms of nutritional value, microenvironment, and protection against natural enemies.     

Morphological and Anatomical Observations of Clasping Leaves of Tamarix L.

This paper deals with some morphological and anatomical adaptabilities of clasping leaves of 13 species of Tamarix L. in China. These xeromorphic leaves posses some conspicuous characteristics as follows: 1 ) The ratio of the leaf surface area to its volume is low; 2) The numerous, small stomata are deeply sinked in the surface of the epidermis; 3) The palisade tissue is only found in the abaxial part and the spongy tissue in the adaxial part, which are quite different from most of the dorsivcntral leaves; 4) The upper epidermis of these leaves is extended a different degree into the epidermis of stem. These characteristics may be considered as an expression of xeric habits resulting from desert adaption.     

Leaf anatomy of the Pittosporaceae R. Br.

WILKINSON, H. P., 1992. Leaf anatomy of the Pittosporaceae R. Br. An anatomical study of the leaves of 58 species representing all nine genera has been made. The anatomical characters found to be of most use in distinguishing taxa are: in surface view-cuticular architecture as seen with the SEM, stomatal outline, occasionally stomatal density, presence/absence of hairs, hair type in adult leaves; in transverse section-petiole/midrib outline, midrib number of vascular bundles and number of secretory ducts, adaxial epidermis in 1/2 layers, dimensions of adaxial epidermal cells, thickness of outer wall of adaxial epidermis, occasionally chlorenchyma interrupted/not interrupted above the midrib vascular tissue in Pittosporum species; leaf margin.     

Ontogenetic differences in mesophyll structure and chlorophyll distribution in Eucalyptus globulus ssp. globulus

Mesophyll structure has been associated with the photosynthetic performance of leaves via the regulation of internal light and CO(2) profiles. Differences in mesophyll structure and chlorophyll distribution within three ontogenetically different leaf types of Eucalyptus globulus ssp. globulus were investigated. Juvenile leaves are blue-grey in color, dorsiventral (adaxial palisade layer only), hypostomatous, and approximately horizontal in orientation. In contrast, adult leaves are dark green in color, isobilateral (adaxial and abaxial palisade), amphistomatous, and nearly vertical in orientation. The transitional leaf type has structural features that appear intermediate between the juvenile and adult leaves. The ratio of mesophyll cell surface area per unit leaf surface area (A(mes)/A) of juvenile leaves was maximum at the base of a single, adaxial palisade layer and declined through the spongy mesophyll. Chlorophyll a + b content showed a coincident pattern, while the chlorophyll a:b ratio declined linearly from the adaxial to abaxial epidermis. In comparison, the mesophyll of adult leaves had a bimodal distribution of A(mes)/A, with maxima occurring beneath both the adaxial and abaxial surfaces within the first layer of multiple palisade layers. The distribution of chlorophyll a + b content had a similar pattern, although the maximum ratio of chlorophyll a:b occurred immediately beneath the adaxial and abaxial epidermis. The matching distributions of A(mes)/A and chlorophyll provide further evidence that mesophyll structure may act to influence photosynthetic performance. These changes in internal leaf structure at different life stages of E. globulus may be an adaptation for increased xeromorphy under increasing light exposure experienced from the seedling to adult tree, similar to the characteristics reported for different species according to sunlight exposure and water availability within their native habitats.     

Radial leaves of the maize mutant ragged seedling2 retain dorsiventral anatomy

ragged seedling2 (rgd2) is a novel, recessive mutation affecting lateral organ development in maize. The mutant phenotype of homozygous rgd2-R leaves is variable. Mild leaf phenotypes have a reduced midrib and may be moderately narrow and furcated; severe Rgd2-R(-) leaves are filamentous or even radial. Despite their radial morphology, severe Rgd2-R(-) mutant leaves develop distinct adaxial and abaxial anatomical features. Although Rgd2-R(-) mutants exhibit no reduction in adaxial or abaxial cell types, areas of epidermal cell swapping may occur that are associated with misaligned vascular bundles and outgrowths of ectopic margins. Scanning electron microscopy of young primordia and analyses of leaf developmental-marker gene expression in mutant apices reveal that RGD2 functions during recruitment of leaf founder cells and during expansive growth of leaf primordia. Overall, these phenotypes suggest that development is uncoordinated in Rgd2-R(-) mutant leaves, so that leaf components and tissues may develop quasi-independently. Models whereby RGD2 is required for developmental signaling during the initiation, anatomical patterning, and lateral expansion of maize leaves are discussed.