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。     

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:     

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     

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     

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     

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.     

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     

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).     

Foliar Nectaries in Mahogany (Swietenia Jacq.)

The pinnately compound leaves of Swietenia spp. have numeroussmall nectaries on petiole, rachis, petiolules, and both surfacesof all leaflets. Nectaries are circular to elongate, eitherlevel with the epidermis or slightly raised or depressed. Thesecretory surface is usually smooth even under high SEM magnification.Each nectary has an outer zone of three or four cell layersof slightly elongate and densely cytoplasmic cells subtendedby two layers of rounded cells with thickened walls and lightlystaining cytoplasm. Proximity of nectaries to vasculature isvariable and seems to be only fortuitous. Meliaceae, Swietenia, mahogany, nectary anatomy, extrafloral nectaries, foliar nectaries     

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).     

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.     

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.     

Steroids from Dysoxylum grande (Meliaceae) leaves

Seven new 23-oxo-cholestane derivatives named as grandol A (1), B (2), C (3), D (4), E (5), F (6), and G (7) were isolated from Dysoxylum grande leaves alongside with a new 3,4-secodammar-4(28)-en-3-oic acid derivative (8). The structures of the compounds were elucidated based on the interpretation of spectroscopic data, and their relative configurations were established by NOESY 2D NMR data. All of the isolates were tested for anti-acetylcholinesterase activity using thin layer chromatography (TLC)-bioautography with fast blue B salt. Only grandol A (1) and B (2) showed positive results, with clear discoloration at a concentration of 12.5 ppm. However, the obtained IC₅₀ values for grandol A and B, when using Ellman’s method, were not significant (>200 μg/ml).     

Terpenes from leaves of Guarea macrophylla (Meliaceae)

The dichloromethane extract from the leaves of Guarea macrophylla (Meliaceae) was submitted to adsorption chromatography. Guai-6-en-10beta-ol, isopimara-7,15-dien-2alpha-ol and cycloarta-23,25-dien-3-one were isolated and identified by spectroscopic data, mainly by 1H and 13C NMR analyses; eight other known terpenoids were also isolated.     

Insecticidal rocaglamide derivatives from Aglaia spectabilis (Meliaceae)

Bark of Aglaia spectabilis collected on the island of Phu Quoc (Vietnam) yielded insecticidal cyclopentatetrahydrobenzofurans of the rocaglamide type including four new natural products. Structure elucidation of the new compounds is described. All rocaglamide derivatives isolated exhibited strong insecticidal activity towards neonate larvae of the polyphagous pest insect Spodoptera littoralis when incorporated into an artificial diet. LC50 values varied from 0.8 to 80 ppm. The most active compounds isolated, methylrocaglate and C-3' hydroxylmethylrocaglate, were similar with regard to their insecticidal activity to the well-known natural insecticide azadirachtin.     

中国分类学文献中Swietenia mahagoni之订正

通过调查,对Swietenia mahagoni的后选模式、S.macrophylla的主模式与中国分类学文献(如《植物分类学报》、《广州植物志》、《中国高等植物图鉴》、《云南植物志》、《广东植物志》、《中国植物志》和《中国高等植物》)的S.mahagoni作比较,证实中国分类学文献将S.mahagoni和S.macrophylla相混,上述分类学文献中的S.mahagon是S.macrophylla King。桃花心木(S.mahagoni(L.)Jacq.)的羽状复叶及小叶较短,小叶长度绝不超过10 cm,果卵球形,长度绝不超过15 cm;而大叶桃花心木(S.macrophylla King)的羽状复叶及小叶较长,总有一部分小叶的长度超过10 cm,果长卵球形,长12~22 cm。     

In vitro culture of Cedrela fissilis Vellozo (Meliaceae)

An efficient micropropagation protocol was developed for Cedrela fissilis (Meliaceae) using nodal segments from juvenile origin for axillary shoot proliferation. Shoot proliferation was significantly affected by salt formulation, explant origin and 6-benzyladenine concentration. Maximum multiplication rates (6–7 new plants were produced in the second subculture cycle per single cotyledonary node cutting) were achieved on Murashige and Skoog media supplemented with 1.25–5.0 M 6-benzyladenine. Addition of -naphthaleneacetic acid to these media caused significant inhibition on shoot proliferation and growth and stimulated callus formation. High frequency callus initiation and synergistic effects on callus growth were achieved on Murashige and Skoog medium supplemented with 6-benzyladenine at either 1.25, 2.5 or 5.0 M combined, respectively, with 2.5, 1.25–5.0 or 5.0 M -naphthaleneacetic acid. Rooting was achieved, after 10–12 days, with 87–100% of the node cuttings on half strength Murashige and Skoog medium either without growth regulators or supplemented with 2.5 M indole-3-butyric acid. Regenerated plants were successfully acclimatized on sterilized sand, for 21 days, but for further plant development the sand:soil (1:1) mixture was the best substrate. The survival rate of plantlets under ex vitro conditions was 100% after 3 months. The optimized micropropagation and callus culture protocols offer the possibility to use the organ/cell culture techniques for vegetative propagation, cryopreservation and secondary metabolism studies.     

Antifeeding activity of limonoids from Khaya senegalensis (Meliaceae)

Abstract: Fifteen B,D-secolimonoids of mexicanolide, rearranged phragmalin, methyl angolensate and glycoside types have been isolated from ether and acetone extracts of the stem bark of Khaya senegalensis (Desr.). The antifeedant activity of the isolated compounds was assessed by conventional choice leaf disc method on the third-instar larvae of Spodoptera littoralis (Boisd.). Khayalactol, 1- O -acetylkhayanolide A, 2-hydroxyseneganolide, khayanolide A, khayanolide D and methyl angolensate displayed strong antifeedant activity at 1000  μ g/ml with antifeedant percentages of 83.8, 61.9, 60.1, 59.5, 57.1 and 55.7, respectively. 2-Hydroxyseneganolide and khayanolide D showed high activity at 500, 300 and 200  μ g/ml while 1- O -acetylkhayanolide A was the only compound that revealed antifeedant activity at a concentration as low as 100  μ g/ml. Antifeedant activity was dose-dependent in some of the isolated compounds. Correlation between antifeedant activity of the isolated compounds and chemical structure was discussed.