Comparative analysis of ultrastructure of glandular trichomes in two Nepeta cataria chemotypes (N. cataria and N. catena var. citriodora)

Glandular trichomes from the leaf surface of Nepeta cataria and N. cataria vai.citriodora have been examined using transmission and scanning electron microscopy. Peltate glands and capitate hairs type I were found on leaves of N. cataria. Both types had single stalk cells. Leaves of N. cataria var. citriodora bore peltate glands with unicellular or bicellular stalk, capitate hairs type I (with unicellular stalk) and capitate hairs type II (with unicellular or bicellular stalk). Peltate glands of N. cataria and of N. cataria var. citriodora were characterized by numerous leucoplasts sheathed by smooth reticular tubules and smooth endoplasmic reticulum; they are proposed to synthesize terpenes. The secretory cells of capitate hairs type I of N. cataria and those of N. cataria var. citriodora had well developed rough endoplasmic reticulum and dictyosomes. They had plastids with protein inclusions. These glands are supposed to produce slime. Capitate hairs type II of N. cataria var. citriodora had no analogs in N. cataria. Their secretory cells exhibited abundance of tubular endoplasmic reticulum and had unsheathed plastids with starch grains. Probably, these glands synthesize terpenes. The results of the study indicate that there is an obvious difference both in morphology and in ultrastructure of glandular trichomes in different chemotypes of N. cataria.     

Nitrogen dynamics in the intact grasses Poa trivialis and Panicum maximum receiving contrasting supplies of nitrogen

The C(3) grass Poa trivialis and the C(4) grass Panicum maximum were grown in sand culture and received a complete nutrient solution with nitrogen supplied as 1.5 mol m(-3) NH(4)NO(3). (15)N tracer techniques were used to quantify the relative use of root uptake and mobilization in supplying nitrogen to growing leaves in intact plants which either continued to receive nitrogen or which received the complete nutrient solution without nitrogen. The allocation of both (15)N-labelled nitrogen uptake and unlabelled mobilized nitrogen indicated that, under their conditions of growth, the sink strength of growing leaves was relatively greater in P. maximum than P. trivialis. The supply of nitrogen by mobilization to side tillers of P. trivialis was completely stopped as the external nitrogen supply was reduced, whilst in P. maximum some allocation of mobilized nitrogen to side tillers, roots and growing leaves was maintained. In both plant species receiving an uninterrupted supply of nitrogen the allocation pattern of mobilized nitrogen differed from that of nitrogen derived from root uptake. Differences exist in the degree to which P. trivialis and P. maximum utilized uptake and mobilization to supply nitrogen to the growing leaves. In P. trivialis roots were always a net sink of mobilized nitrogen, irrespective of the external nitrogen supply. In P. maximum, roots were a net sink of mobilized nitrogen when external nitrogen was withdrawn, but exhibited both source and sink behaviour when nitrogen supply was continued.     

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。     

Sideritis syriaca ssp. syriaca: Glandular trichome structure and development in relation to systematics

Sideritis syriaca ssp. syriaca is a taxon with a low essential oil content. Its leaves bear glandular trichomes of two types: long hairs with a 4-celled head, a 4-celled stalk and a 4-celled foot (reported for the first time in Lamiaceae) and short hairs with a 4–celled head, a unicellular stalk and a unicellular foot. The second type is considered intermediate between the capitate and peltate hairs, common in Lamiaceae, but found in S. syriaca ssp. syriaca. The ontogeny of the trichome types is described. The possible significance of the glandular trichome structure to Lamiaceae systematics is further discussed.     

Glandular trichomes and essential oil constituents ofCalamintha menthifolia (Lamiaceae)

Plant material ofCalamintha menthifolia was collected from two populations grown in the Vikos-Aoos area (NW. Greece). The structure and ontogeny of the glandular trichomes and the chemical composition of the secreted essential oil were studied. The leaves ofC. menthifolia have numerous glandular trichomes of three morphological distinct types: 1) glandular scales with a unicellular foot and stalk, and a 12-celled head, 2) glandular hairs with a unicellular foot and stalk, and a unicellular pear-shaped head and 3) glandular hairs with a unicellular foot, a bicellular stalk and a unicellular elongated head. Qualitative and quantitative GC-MS analyses of the essential oils revealed piperitone oxide as the main constituent in both populations. In the light of these results the relationships beweenC. menthifolia and other members of theSatureja group as well as its taxonomy are discussed.     

A New Species of Gigantochloa Kurz ex Munro (Poaceae: Bambusoideae) from Yunnan Province,China

A new species of Gigantochloa Kurz ex Munro, Gigantochloa callosa NH. Xia, Y. Zeng & RS. Lin was described and illustrated. It is differed from Gparvifolia (Brandis ex Gamble) TQ. Nguyen by its smaller size; culm sheath proper covered with both dark brown and silvery appressed hairs abaxially; ligules 2-3mm tall, entire; leaf ligules 2-3mm tall, entire; one side of the apex of leaf sheath developed into a 2-3mm long, thin, scale like callus.     

ASSOCIATION OF MUCILAGE WITH THE LIGULE OF SEVERAL SPECIES OF SELAGINELLA

Mucilage bodies of protein and some polysaccharide were closely associated with ligules of Selaginella kraussiana (Kunze) A. Braun grown in the greenhouse, and Selaginella wallacei Hieron. and Selaginella oregana D.C. Eat. from natural habitats. With S. wallacei and S. oregana, several mucilage bodies were associated with some ligules. No mucilaginous material was associated with the ligules of Selaginella douglasii Hook, et Grev., Selaginella densa Rydb. or Selaginella apoda (L.) Fernald from natural habitats. When stem tips of S. kraussiana and S. douglasii were placed in sterile culture on a medium with sucrose, massive amounts of mucilage appeared around the ligules in the tight interstices of the stem tip leaves and extended out on the surface of the leaves. The mucilage from a cultured stem tip of S. kraussiana contained 0.034 μgm of protein, 14.6 μgm of apparent glucose equivalents as polysaccharide and no significant amounts of phenolics. In stem tips with tightly appressed leaves, either ligules or young leaves could have produced the mucilage; however, in more mature regions of the stem where internodal elongation had separated the leaves, mucilage coated only the apical portions of the ligules and was not associated with leaves. No other possible source of mucilage (bacteria or fungi) was detected among the leaves. When stem tips of S. wallacei, S. densa and S. apoda were placed in culture, mucilage was not produced. Since mucilage is closely associated with the ligule of some species of Selaginella growing in nature, the greenhouse, or tissue culture, the ligule may be glandular.     

中国云南巨竹属一新种

描述了中国巨竹属一新种——小巨竹GigantochloacallosaN．H．Xia,Y．Zeng＆R．S．Lin并绘制了图版。该种与Gigantochloaparvifolia（Brandisex Gamble）T．Q．Nguyen相似,区别在于此种各部分较G．parvifolia较小;箨鞘背面贴生深褐色与银灰色短硬毛,箨舌高2～3mm,全缘;叶舌高2～3mm,全缘;叶鞘背面与叶柄连接处一侧有一高2～3mm的半圆形薄鳞片状突起。     

多花黄精五个居群叶片的比较解剖学研究

利用石蜡切片技术、叶表皮离析法和电镜扫描技术,对多花黄精五个居群的叶片进行了比较解剖学研究。观察发现:多花黄精五个居群的叶肉细胞中均具有内含针晶束的异细胞,叶表皮细胞为长方形、不规则形或椭圆形,垂周壁一般为平直和弧形;有的居群下表皮有单细胞表皮毛分布。在扫描电镜下,角质层纹饰多为鳞片状。结果表明叶表皮特征,如:气孔器大小、气孔器指数、气孔器密度、气孔器分布特征、角质层纹饰及表皮毛的分布等受环境因子影响较大,同种不同居群间有一定差异,而叶肉的构成、内含物(如针晶束)、气孔器类型、表皮细胞形状等具有种间稳定性,可以作为分类的依据。     

中国云南巨竹属一新种

描述了中国巨竹属一新种——小巨竹Gigantochloa callosa NH. Xia, Y. Zeng & RS. Lin并绘制了图版。该种与Gigantochloa parvifolia (Brandis ex Gamble) TQ. Nguyen相似,区别在于此种各部分较Gparvifolia较小;箨鞘背面贴生深褐色与银灰色短硬毛,箨舌高2~3mm,全缘;叶舌高2~3mm,全缘;叶鞘背面与叶柄连接处一侧有一高2~3mm的半圆形薄鳞片状突起。     

A note on the hairy achenes of four African species of Scleria Bergius (Cyperaceae)

Surface features of hirsute achenes of four African species of Scleria have been examined by SEM. All bear unicellular, terete hairs with swollen bases. As the achenes mature and dry, the hairs collapse, except for their partly silicified bases, which appear as pit-like depressions from which the now-flattened hairs emerge. If the achene surface is not smooth the hairs are localized on the interlacunar ridges. In addition to the hairs, three of the four species examined show minute papillate protuberances from the silicified outer tangential walls of the epidermal cells. These papillae form a further ornamentation to the achenes visible only at high magnification. The fourth species entirely lacks these papillae.     

Structures, Components and Functions of Secretory Tissues in Houttuynia cordata

Houttuynia cordata Thunb., traditionally used as a therapeutic plant in folk medicine, has shown antioxidant and anticancer activities. The species, as a core component of paleoherbs, is normally characterized based on the presence of different types of secretory tissue： oil cells, three types of secretory cells and glandular hairs. The aim of this work was to study the structural, componential, and the functional characteristics of the secretory tissues in both the floral and vegetative parts. The results indicate that oil cells and secretory cells are distributed in all organs of the plant, while glandular hairs are situated on the aerial stems and leaves. Both oil cells and glandular hairs initiate from the protoderm, but their developmental processes are different. Although three types of secretory cells initiate from different primary meristems, the developmental patterns of different secretory cells are the same. Also, although the origins of secretory cells are different from oil cells, their early developmental processes are the same. Histochemical results show that oil cells, secretory cells and glandular hairs produce flavonoids, phenolic compounds, tannins, lipids, aldehyde and ketone-compounds. In addition, there are terpenoids and pectic-like substances in oil cells, alkaloids in secretory cells of aerial stems, and terpenoids and alkaloids in glandular hairs. These compounds play very important roles in protecting plants from being eaten by herbivores （herbivory） and infected by microbial pathogens. The oil cell and secretory cell, as unicellular secretory tissues, are intermediates between the primitive surface glandular and secretory cavity and canal during the evolution of secretory structures.     

贺兰山15种旱生灌木叶表皮扫描电镜观察

对15种天然分布在宁夏贺兰山荒漠地区的旱生灌木叶表皮进行扫描电镜观察发现,这些植物叶的上、下表皮细胞角质膜加厚,且分布有大量的表皮毛,有单细胞毛和多细胞毛;气孔器被表皮毛覆盖,均为内陷气孔。这些形态结构是植物适应干旱环境的典型特征。     

中国产委陵菜属叶表皮毛的研究

在光学显微镜和实体解剖镜下对28种和变种国产委陵菜属植物的叶表皮毛进行了研究,结果如下：1．在所观察的植物中,有4种类型叶表皮毛的存在,即：单细胞直的不分支的毛;单细胞卷曲的不分支的毛;腺毛;星状毛。2．叶表皮毛的种类在本属植物中具有稳定性,因此具有一定的分类学价值。3．腺毛在所观察的植物中普遍存在。4．讨论了金露梅、银露梅、小叶金露梅的系统归属。     

Vascular Organization and some Aspects of the Morphology of the Rhizome of Gymnogrammitis dareiformis

Gymnogrammitis dareiformis, the taxonomically controversialdavalliaceous fern has a parenchymatous rhizome, in the groundtissue of which groups of 1–16 thick-walled cells (withpeg-like protrusions on inner walls) are irregularly scattered.Paleae clothing the rhizome are basally attached, gland-tippedand bearing unicellular marginal hairs. The vascular cylinderis a radially-symmetric dictyostele dissected by spirally-arrangedleaf gaps into slender reticulated meristeles. Some of the dorso-laterallyplaced leaves alone are fully developed; most other leaves aresuppressed and some are highly reduced (the larger reduced leavesappear as protrusions on the rhizome and have a well-formedleaf base). The leaf trace of developed as well as the largerreduced leaves is a channel-shaped loose reticulum of four vascularstrands; the trace of the reduced leaves is smaller and endsblindly at the leaf base. The leaf trace of the smaller reducedleaves is vestigial and represented often by only a pair ofvascular strands fusing into one and ending blindly in the cortexof the rhizome. The leaf trace of suppressed leaves fuses backwith the stelar cylinder, forming a convex reticulum bridgingthe sides of the leaf gap. It is suggested that the characteristic stelar organizationof the Davalliaceae is derived by suppression of leaves froma radiallysymmetric dictyostele with spirally-arranged leafgaps as found in Nephrolepis and that Gymnogrammitis with itsreduced and suppressed leaves indicates the process of transition.The creeping solenostelic rhizome with two-ranked leaf arrangementcould be derived from an erectgrowing dictyostelic one by supppressionof leaves.     

Structure and formation of fibrillar mucilages in seed epidermis cells

Protoplasma - The seed epidermis cells of differentRuellia species rupture the cuticle to form unicellular hairs. They become filled with mucilage which consists of very long elementary fibrils and...     

百部科植物叶表皮特征及其分类学意义

利用光学显微镜和扫描电子显微镜,对百部科4属30种植物的叶表皮微形态特征进行了观察研究。结果显示,叶表皮细胞形状仅有无规则形和多边形2种,垂周壁式样有深波状、浅波状和平直-弓形3种;表皮角质层纹饰微形态多样化,绝大多数物种的叶片表面不具有毛被,仅少数植物叶片表面具单细胞毛;气孔器主要分布在下表皮,仅Stemona prostrata I.R.H.Telford、S.cochinchinensis Gagnep、S.rupestris Inthachub、S.pierrei Gagnep和S.involuta Inthachub 5个种上下表皮均有气孔器;气孔形状均为椭圆形,而气孔器类型均为无规则型。百部科叶表皮微形态特征在属间有一定差异,但在属内各种间没有明确规律,表明该类群应该是一个自然的单系类群。由于百部科植物采样困难,在缺乏系统进化树数据的情况下,这些微形态特征可为探讨百部科不同种类的分类学、生物地理及其生态适应性提供部分新证据。     

木香薷腺毛形态结构发生发育规律的研究

采用常规石蜡切片法及扫描电镜技术对木香薷(Elsholtzia stauntoni Benth)腺毛发生发育及其规律进行了研究。结果表明：木香薷表皮上主要有两种表皮毛：无分泌细胞的表皮毛与有分泌细胞的腺毛。前者包括单细胞乳头状毛、2~3细胞管状毛、分枝状毛及多细胞管状毛;后者包括头状腺毛与盾状腺毛。成熟头状腺毛头部由1、2或4个分泌细胞构成,头部呈圆球形或半圆球形;成熟盾状腺毛头部由8~12个分泌细胞构成,分泌细胞横向扩展形成盾状头部。木香薷腺毛主要在茎端幼叶处大量发生,从茎端第一对幼叶处开始产生;从幼叶期到成熟期均有腺毛发生,大部分腺毛在幼叶期发生发育,只有极少部分在叶的成熟期进行发生发育。     

Conserved and unique features of the maize (Zea mays L.) root hair proteome

Root hairs are unicellular extensions of specialized epidermis cells. Under limiting conditions, they significantly increase the water and nutrient uptake capacity of plants by enlarging their root surface. Thus far, little is known about the initiation and growth of root hairs in the monocot model species maize. To gain a first insight into the protein composition of these specialized cells, the 2573 most abundant proteins of maize root hairs attached to four-day-old primary roots of the inbred line B73 were identified by combining 1DE with nanoLC-MS/MS in a shotgun proteomic experiment. Among the identified proteins, homologues of 252 proteins have been previously associated with root hair formation and development in other species. Comparison of the root hair reference proteome of the monocot species maize with the previously published root hair proteome of the dicot species soybean revealed conserved, but also unique, protein functions in root hairs of these two major groups of flowering plants.