Extrafloral Nectaries in Acacia mangium

Our microscopy studies describe the anatomy of extrafloral nectaries on the abaxial side of the basal part of every leaf stalks of Acacia mangium. The lens-like nectary expands with the development of the leafstalk, peaks at the stage at which the leafstalk itself has reached its mature size. The nectary is composed of numerous small parenchyma cells and a nectar cavity in which the nectar is pooled. Those small parenchyma cells are divided into nectariferous tissue and epithelial cells, which line the lumen of the nectar cavity, and secretes the nectar into the same. Each nectary is surrounded by several vascular bundles, which probably afford the nectar. In addition to the microscopic observation, the chemical constituents of the nectar are analyzed by NMR, and it mainly consists of sugars with 60 % sucrose, 25 % glucose and 15 % fructose.     

浆果楝中的新木脂素

从浆果楝（Cipadessa baccifera）中分离得到两个木脂素,其化学结构通过波谱方法鉴定为：（-）-9′-O-（E）-coumarate-5,5′-dimethoxylariciresinol（1）和（＋）-9′-O-（E）-feruloyl-5,5′-dimethoxylariciresinol（2）。其中化合物1为新化合物。     

浆果楝中的新木脂素(英文)

从浆果楝(Cipadessa baccifera)中分离得到两个木脂素,其化学结构通过波谱方法鉴定为:(-)-9′-O-(E)-coumarate-5,5′-dimethoxylariciresinol(1)和(+)-9′-O-(E)-feruloyl-5,5′-dimethoxylariciresinol(2)。其中化合物1为新化合物。     

The Extrafloral Nectaries of Sambucus nigra

The structure and ultrastructure of the extrafloral nectariesof Sambucus nigra L. were studied. These nectaries are stalk-likeand occur at the bases of the leaves and leaflets. The nectariferoustissue occurs at the top of the nectary and is continuous withthe single central vascular bundle. The nectariferous cellshave a dense cytoplasm and contain a well developed endoplasmicreticulum. With the commencement of nectar secretion disintegrationof the nectariferous cells takes place. This process startsat the summit of the nectary and proceeds downwards. The questionas to whether the process of secretion is holocrine or merocrineis discussed. Sambucus nigra, Extrafloral nectary, nectariferous cells, disintegration of cells     

Extrafloral Nectaries in Aspen (Populus tremuloides): Heritable Genetic Variation and Herbivore-induced Expression

Annals of Botany 100:     

Ultrastructure and Secretion of Extrafloral Nectaries of Plumeria rubra L.

Extrafloral nectaries situated on the adaxial side of the petiolebase are differentiated into a long head, comprising subepithelialground tissue surrounded by a layer of elongated palisade-likeepithelial cells and a short stalk from the nectary meristem.Many ultrastructural changes occur in epithelial and subepithelialcells of the nectary, from the young to secretory stages, suchas an increase in the amount of cytoplasm rich in mitochondriawith well developed cristae, rough endoplasmic reticulum (rER),smooth endoplasmic reticulum (sER) tubules and Golgi bodies.Plasmalemma invaginations with secretory vesicles occur longthe radial walls. Substantial amounts of secretory materialaccumulate in the gap between the radial walls and subcuticularspace, probably carried by the secretory vesicles from the cytoplasmat the secretory stage. Before cessation of secretion the cytoplasmbecomes vesiculated and the volume of the vacuome increases.At the post secretory stage, cytolytic processes and death ofcells occur. The subepithelial cells attain their maturity priorto epithelial cells. Histochemical localization reveals thepresence of lipids, proteins and insoluble polysaccharides withinthe epithelial cells and in the secretory material depositedin the subcuticular space as well as the gap between the radialwalls of the epithelial cells and outside the cuticle. Fine structure, nectary, Plumeria rubra, granulocrine secretion     

Characteristics of Nectar Secretion by the Extrafloral Nectaries of Ricinus communis

The characteristics of nectar secretion by excised extrafloralnectaries of Ricinus have been examined. Secreted nectar wasfound to contain three sugars: sucrose, glucose and fructose,with glucose and fructose occurring in a 1: 1 ratio. All threesugars supported secretion when used in the culture medium andthe yield of nectar sugar was found to be concentration-dependent.Other sugar sources failed to support secretion. Experimentsusing ¹⁴C-sugars and ¹⁴CO₂ fed to intact plants allowed themovement of sugars through the nectary to be examined. Sucrosesynthesis occurs when excised glands are fed glucose and thisoccurs very early in the transport through the nectary. Themain sugar transported was sucrose, with little hydrolysis occurringuntil the final step of secretion. There was no evidence thatsucrose hydrolysis occurs either by invertase in the nectaror by a microbial flora. Inhibitors of respiration were foundto inhibit secretion as did anaerobiosis. Temperature also hada marked effect, with a temperature coefficient of 1.8. However,secretion of sucrose was not affected by anaerobic conditions,low temperatures or inhibitors of respiration as markedly asthat of glucose and fructose. Electron microscopy revealed the presence of a thickened andheavily stained wall at the inner border of the secretory epidermallayer. This wall contained numerous plasmodesmata at a frequencyof 14 per µm² and may represent an apoplastic barrier.Light microscope cytochemistry revealed that acid phosphataseis primarily located in the nectiferous tissue, while ATPaseis concentrated in the epidermis. The possibility that the nectarycontains two pathways for sucrose secretion, both apoplasticand symplastic, is discussed. Key words: Invertase, nectary, plasmodesmata, Ricinus communis, sucrose     

Extrafloral Nectaries of Dioscorea rotundata Poir.: Their Structure and Secretions

Extrafloral nectaries are to be found embedded in the leaf laminaof Dioscorea rotundata Poir., with a pore opening on to thelower leaf surface. The nectaries comprise small, densely cytoplasmiccells and are bounded by a layer of cells containing littleor no cytoplasm. Their secretion contains sucrose, fructoseand glucose with traces of galactose. Ninhydrin-positive compoundsare also present. Diosorra rotunrdata Poir, extrafloral nectaries, secretion, ultrastructure     

Structure and Development of the Axillary Complex and Extrafloral Nectaries in Capparis retusa Griseb.

Abstract: The structure, organization and development of the axillary complex and extrafloral nectary in Capparis retusa Griseb. was analysed for the first time. The axillary complex presents three uniserial descending buds. Subordinated shoots originate from the distal and middle bud, while the proximal bud is usually quiescent. Close to the top of the axillary complex there is a subglobulous and umbilicated extrafloral nectary, normally visited by nectivore ants; a chronological coincidence between secretion, production and ant patrolling activities has been observed. The nectary structure differentiates at the second caulinar node, from an axillar meristem separated from the surrounding cells by a shell zone. On the fourth node a remarkably developed nectary primordium can be observed, inside which procambial strands develop acropetally. In the central region of the nectary primordium homogenous parenchyma differentiates progressively, later acquiring characteristics of nectariferous tissue. The mature nectary is vascularized by xylem and phloem, and the procambial differentiation is completed in a basipetal way. The first serial bud differentiates at the third node, from meristem cells near the base of its supporting leaf. The complex nodal structure with three buds completes its development at the eighth caulinar node. Ramular traces are observed as vascular semicylinders penetrating into the base of the buds to constitute a vascular system similar to that of the shoot. The scheme is repeated in the extrafloral nectary, giving rise to prolific branching in the periphery of the nectariferous tissue.     

The Extrafloral Nectaries of Cotton: I. FINE STRUCTURE OF THE SECRETORY PAPILLAE

The fine structure of the secretory papillae of the extrafloralnectaries of cotton (Gossypium hirsutum) is described. The cellscontain a dense cytoplasm with the rough endoplasmic reticulumbeing particularly prominent. The cuticle covering the papillaehas a typical two-layered appearance and is detached from thewall in secretory cells. With maturity, the lateral walls ofthe stalk cell at the base of each papilla become impregnatedwith cuticle-like electron-opaque material. The frequency anddistribution of plasmodesmata have been estimated in all wallsof the papillae. The periclinal walls are traversed by numerousplasmodesmata (about 16 per µ m² in the distal wall ofthe stalk cell) which, in general, change from a simple to amore complicated structure during nectary development. The resultsare discussed in relation to the role of the ER in nectar secretionand are considered to support the view that pre-nectar followsa symplastic pathway from the phloem to the secretory cells. Key words: Gossypium hirsutum, Secretory papillae, Nectary     

The Influence of Host Plant Extrafloral Nectaries on Multitrophic Interactions: An Experimental Investigation

A field experiment was conducted with outplantings of the native perennial shrub Senna mexicana var. chapmanii in a semi-natural area adjacent to native pine rockland habitat in southern Florida. The presence of ants and the availability of extrafloral nectar were manipulated in a stratified random design. Insect communities were monitored and recorded over a period of six months with a view to addressing three main questions. Do ants provide biotic defense against key herbivores on S. chapmanii? Is the presence of ants on S. chapmanii mediated by EFN? Finally, are there ecological costs associated with the presence of ants on S. chapmanii, such as a reduction in alternative predator or parasitoid numbers? Herbivores on S. chapmanii included immature stages of three pierid butterflies, and adult weevils. Eight species of ants were associated with the plants, and other predators included spiders, ladybugs, wasps, and hemipterans. Parasitic, haemolymph-sucking midges (Ceratopogonidae) and parasitoid flies were also associated with the caterpillar herbivores, and possibly the extrafloral nectaries of the plants. The presence of ants did not appear to influence oviposition by butterflies, as numbers of lepidopterans of all developmental stages did not differ among treatments. Significantly more late instar caterpillars, however, were observed on plants with ants excluded, indicating that ants remove small caterpillars from plants. Substantially more alternative predators (spiders, ladybugs, and wasps) were observed on plants with ants excluded. Rates of parasitization did not differ among the treatments, but there were substantially fewer caterpillars succumbing to virus among those collected from control plants.We provide a rare look at facultative ant-plant mutualisms in the context of the many other interactions with which they overlap. We conclude that ants provide some biotic defense against herbivores on S. chapmanii, and plants benefit overall from the presence of ants, despite negative impacts on non-ant predators.     

Incidence of Extrafloral Nectaries and Their Relationship with Growth and Survival of Lowland Tropical Rain Forest Trees

Mutualistic relationships between organisms have long captivated biologists, and extrafloral nectaries, or nectar‐producing glands, found on many plants are a good example. The nectar produced from these glands provides food for ants, which may defend the plant from potential herbivores in turn. However, relatively little is known about their impact on the long‐term growth and survival of plants that produce them. To better understand the ecological significance of extrafloral nectaries, we examined their incidence on lowland tropical rain forest trees in Yasuní National Park in Amazonian Ecuador, and collated data from two other tropical lowland forest sites (Barro Colorado Island, Panamá and Pasoh Forest Reserve, Malaysia). At Yasuní, extrafloral nectaries were found on 137 of 1123 species censused (12.2%), widely distributed among different angiosperm families. This rate of incidence is high but consistent with other tropical locations. Furthermore, this study adds 18 new genera and two new families (Urticaceae and Caricaceae) to the list of taxa exhibiting extrafloral nectaries. Using demographic data from long‐term forest dynamics plots at each site, we compared the growth and mortality rates of species with extrafloral nectaries to those without. After controlling for phylogeny, no general relationship between extrafloral nectary presence and demographic rates could be detected, suggesting little demographic signal from any community‐wide ecological effects.     

Sooty Mould on Hibiscus rosa‐sinensis Caused by Leptoxyphium kurandae is Associated with Extrafloral Nectaries

In August 2013, sooty mould was observed on Chinese hibiscus (Hibiscus rosa‐sinensis) in a propagation nursery in Seoul, Korea. The sooty mould initially developed at the junction between the leaf blade and leaf petiole and then dispersed along the vein on the abaxial surface. The fungal growth pattern on the plants was quite different from general sooty moulds growing on honeydew secreted by insects on the plants. On the basis of the morphological characteristics and phylogenetic analysis using the internal transcribed spacer rDNA, this fungus was identified as Leptoxyphium kurandae. A pathogenicity test was carried out to fulfil Koch's postulates. Through field observation and a pathogenicity test, we found an association between the sooty mould and extrafloral nectaries. To our knowledge, this is the first report of sooty mould caused by L. kurandae on the extrafloral nectaries of H. rosa‐sinensis.     

Foliar Nectaries and Glandular Trichomes in Catalpa (Bignoniaceae)

The Tertiary relic genus Catalpa, containing 11 Old and New World species, has multiple nectaries in the junctions of the major veins on the lower leaf surfaces. The generalized structure of the nectaries consists of a single, basal cell, and a single row of vertically oriented secretory cells. The nectaries are small, and contain no vascular tissue. Glandular and nonglandular trichomes are also present on the leaves. The glandular trichomes are structurally very similar to the nectaries, and probably are their precursors. Development of multiple nectaries in the lower leaf surface vein axils is considered to be an advanced strategy for attracting beneficial insects to control or minimize the effects of herbivorous insects. Chinese and American species of Catalpa are closely related, and have greater numbers of nectaries in more locations on the lower leaf surface than west Indian species. Herbivory pressures in the West Indies are postulated to be lower than on the continents, i.e. Asia and North America.     

Limonoids from Turraea floribunda (Meliaceae)

Six novel limonoids and limonoid derivatives, turraflorins D-I along with the known turraflorins A and B have been isolated from seed of the South African Turraea floribunda (Meliaceae).     

Nectaries and reproductive biology of Croton sarcopetalus (Euphorbiaceae)

Flower morphology, nectary structure, nectar chemical composition, breeding system, floral visitors and pollination were analysed in Croton sarcopetalus , a diclinous-monoecious shrub from Argentina. Male flowers have five receptacular nectaries, with no special vascular bundles, that consist of a uniserial epidermis with stomata subtended by a secretory parenchyma. Female flowers bear two different types of nectaries: inner (IN) and outer (ON) floral nectaries. IN, five in all, are structurally similar to the nectaries of male flowers. The five ON are vascularized, stalked, and composed of secretory, column-shaped epidermal cells without stomata subtended by secretory and ground parenchyma. In addition, ON act as post-floral nectaries secreting nectar during fruit ripening. Extrafloral nectaries (EFN) are located on petioles, stipules and leaf margins. Petiolar EFN are patelliform, stalked and anatomically similar to the ON of the female flower. Nectar sampled from all nectary types is hexose dominant, except for the ON of the female flower at the post-floral stage that is sucrose dominant. The species is self-compatible, but geitonogamous fertilization is rarely possible because male and female flowers are not usually open at the same time in the same individual, i.e. there is temporal dioecism. Flowers are visited by 22 insect species, wasps being the most important group of pollinators. No significant differences were found in fruit and seed set between natural and hand pollinated flowers. This pattern indicates that fruit production in this species is not pollen/pollinator limited and is mediated by a wide array of pollinators.     

Extrafloral nectaries in Philodendron (Araceae): distribution and structure

Extrafloral nectaries (EFNs) are involved in animal–plant interactions that lead to protection against herbivory. The presence of EFNs in Araceae is rare, besides Philodendron, there is report for only two other genera. With the aim to investigate the occurrence of EFNs in Philodendron and to describe the distribution patterns and structural organization of these glands, 75 Philodendron spp. were examined, 16 of which were selected for study by light microscopy. Three Homalomena spp. were also examined for EFNs, but these were not found. Philodendron martianum was employed as a model for additional study using scanning and transmission electron microscopy. The studied EFNs showed a high degree of structural similarity. They were present in the prophyll, leaf and spathe, becoming functional in young organs. In surface view, EFNs consisted of small areas and showed one or more stomata through which secretions were released. The secretory cells formed a globular region surrounded by ground parenchyma. In P. martianum, nectariferous parenchyma cells exhibited typical features of cells with high metabolism related to nectar secretion. These results allow us to infer that EFNs have a widespread occurrence in Philodendron, and they remain an exclusive character for this group. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180 , 229–240.     

茎花葱臭木化学成分的研究

从茎花葱臭木种子中分离得到5个化合物,经理化与波谱分析鉴定为β-谷甾醇(1)、没食子酸乙酯(2)、胡萝卜苷(3)、1-O-β-D-吡喃葡萄糖基-(2S,3S,4R,8Z)-2-N-(2 ′-羟基二十四烷酰氨基)十八二氧鞘氨-8-烯(4)和2,3,2″,3″-四氢穗花杉双黄酮(5).这5个化合物均首次从该植物中分离得到.其中化合物5进行细胞毒活性测试,没有显示抑制活性.     

Oleanane trietrpenoids from Cedrela montana (Meliaceae)

Two new oleanane-type triterpenes, characterized as 3-oxo-11alpha,12alpha-epoxy-oleanan-28,13beta-olide and 3-oxo-olean-11-en-28,13beta-olide , were isolated from the fruits and seeds of Cedrela montana (Meliaceae). In addition, the known compounds oleanonic acid, a mixture of beta-sitosterol and stigmasterol, and the limonoid photogedunin were also isolated. The structures of the new compounds were established by spectroscopic methods, including 2D NMR.     

Tetranortriterpenoid derivatives from Turraea parvifolia (Meliaceae)

The methanol extract of the seeds of Turraea parvifolia has yielded seven novel triterpenoid derivatives: 12alpha-acetoxyazadironolide, turraparvin A (12alpha-acetoxy-7alpha,23-dihydroxy-24,25,26,27-tetranor-3-oxoapotirucalla-1,14,20(22)-trien-21,23-olide), turraparvin B (12alpha-acetoxy-7alpha,21-dihydroxy-24,25,26,27-tetranor-3-oxoapotirucalla-1,14,20(22)-trien-23,21-olide), turraparvin C (7alpha,12alpha-diacetoxy-21-hydroxy-24,25,26,27-tetranor-3-oxoapotirucalla-1,14,20(22)-trien-23,21-olide), 11-epi-21-hydroxytoonacilide, 11-epi-23-hydroxytoonacilide and turraparvin D (12alpha-acetoxy-7alpha-hydroxy-24,25,26,27-tetranor-3-oxoapotirucalla-1,14,20(22)-trien-21,23-lactam).