An X-ray Microanalysis Study of the Salt Glands and Intracellular Calcium Crystals of Tamarix

X-ray microprobe analyses of the secreted salts from glandsof 20 Tamarix aphylla (L.) Karst trees growing in alluvial soilsin the north western district of Victoria, Australia, show thatthe glands secrete a variety of elements including calcium,magnesium and sulphur. However, sodium, potassium and chloride,common ions reported to be secreted predominantly in other studies,are present in relatively low amounts in the secreted salts.Calcium, the major cationic element in the secretory productof the gland, was not detected in the symplasm of the secretoryand collecting cells or in the vacuoles of the collecting cells.Some evidence indicates that silicon may be secreted by theglands but further corroboratory data are required. Our resultssupport previous suggestions that the glands of Tamarix havea low level of selectivity. Large, spherical aggregates of calcium crystals were observedin the vacuoles of the mesophyll cells and quantitative X-raymicroanalysis suggested that the chemical composition of thecrystalline aggregates was CaSO₄, 2H₂O. The predominant elementsin the vacuolar sap were magnesium and sulphur, probably presentas MgSO₄, whereas the major elements in the cytoplasm were potassium,sulphur and phosphorus. In Tamarix aphylla the calcium contentof the leaf appears to be regulated by both the secretion ofcalcium salts from the leaf and by intracellular calcificationin mesophyll cells.Copyright 1994, 1999 Academic Press X-ray microanalysis, Tamarix, salt gland, secretion, salts, ions, calcium crystals, compartmentation     

Ultrastructural features of the salt gland of Tamarix aphylla L.

Summary The salt gland in Tamarix is a complex of eight cells composed of two inner, vacuolate, collecting cells and six outer, densely cytoplasmic, secretory cells. The secretory cells are completely enclosed by a cuticular layer except along part of the walls between the collecting cells and the inner secretory cell. This non-cuticularized wall region is termed the transfusion are (Ruhland, 1915) and numerous plasmodesmata connect the inner secretory cells with the collecting cells in this area. Plasmodesmata also connect the collecting cells with the adjacent mesophyll cells.There are numerous mitochondria in the secretory cells and in different glands they show wide variation in form. In some glands wall protuberances extend into the secretory cells forming a labyrinth-like structure; however, in other glands the protuberances are not extensively developed. Numerous small vacuoles are found in some glands and these generally are distributed around the periphery of the secretory cells in association with the wall protuberances. Further, an unusual structure or interfacial apparatus is located along the anticlinal walls of the inner secretory cells. The general structure of the gland including the cuticular encasement, connecting plasmodesmata, interfacial apparatus, and variations in mitochondria, vacuoles, and wall structures are discussed in relation to general glandular function.     

Programmed cell death in salt glands of <Emphasis Type="Italic">Tamarix aphylla</Emphasis> L.: an electron microscope analysis

Background  

Tamarix aphylla is a halophyte growing in soils rich in NaCl. Leaves of Tamarix aphylla develop numerous salt glands, which initiate, secrete NaCl, become senescent and eventually die, as part of a programmed process. Dead glands are replaced by new ones, so that only active glands exist on the leaves. Most importantly, these glands remove excess NaCl from the tissues, which protects against hyperosmotic phenomena.     

The Ultrastructure of the Digestive Glands in Pinguicula vulgaris L. (Lentibulariaceae) Relative to their Function. II. The Changes on Stimulation

The secretory cells of the digestive glands remain highly activeduring the entire period of prey digestion and absorption ofnutrients. They appear to play a major role in gland activity.A model of the digestive gland's activity on stimulation isproposed. It is very similar to that suggested earlier for Dionaeamuscipula. After the digestion and absorption cycle, destructiveprocesses are initiated in the glands. These appear similarto those observed in the glands of the ageing, unstimulatedleaf and are not associated with feeding. Pinguicula vulgaris L. carnivorous plant, digestive glands, ultrastructure, protein secretion absorption, senescence     

Anatomy and Distribution of Secretory Glands and Other Emergences in Tofieldia (Liliaceae)

Secretory glands are rare in Liliaceae. We surveyed the scapesof herbarium specimens of all 23 species of Tofieldia and found13 with glabrous scapes, two with sparse emergences on a fewspecimens, and eight that invariably bore emergences which rangedfrom clearly secretory to clearly non-secretory. Gland-bearingspecies are concentrated in North America. Paraffin sectionsshowed anatomical differences among the emergences. Field-fixedscapes of T. glutinosa, with secretory glands, were studiedby the paraffin method and scanning electron microscopy. Themost distinctive feature is a distal pore where usually oneor two epidermal cells appear to be lacking, thereby exposingthe internal, presumably secretory, cells. The secretory productin T. glutinosa is tasteless, colourless, and sticky to thetouch.     

The Relationship Between Oil Gland and Fruit Development in Washington Navel Orange (Citrus sinensis L. Osbeck)

Changes in structure, size and number of oil glands locatedin the fruit rind were assessed in developing fruit of the WashingtonNavel orange (Citrus sinensis L. Osbeck) from pre-anthesis tofruit maturity. Initiation of oil glands was found to be restrictedto early fruit development. Glands continued to develop throughoutfruit growth, until all reached maturity by a fruit size of30 to 50 mm diameter. Mature glands continued to enlarge withfruit growth. Mature fruit had between 8 000 and 12 000 oilglands. Anatomical studies of the fruit rind were carried outusing light microscopy on samples prepared by different tissueprocessing methods. Glands were found to develop from a clusterof cells adjacent to the fruit epidermis, into a structure consistingof a central cavity surrounded by several layers of epithelialcells. All glands were joined to the fruit epidermis, irrespectiveof their stage of development. Neither lignin nor suberin waspresent in the gland. Gland cavity formation appeared to involveschizogeny. Copyright 2001 Annals of Botany Company Washington Navel orange, Citrus sinensis L. Osbeck, fruit development, secretory cavity, oil gland, image analysis, light microscopy     

THE FINE STRUCTURE AND FUNCTION OF THE SALIVARY GLANDS OF NUCELLA LAPILLUS (GASTROPODA: MURICIDAE)

The fine structure of the tubular and acinous salivary glandsof Nucella lapillus (L.) has been studied and some histochemicaland enzyme tests have been carried out. The clusters of subepithelialcells of the tubular glands secrete a glycoprotein composedof chains of tubular macromolecules resembling secretions knownto have adhesive properties which may assist in boring. Thesecretion is rich in disulphide groups, as are many toxins,and is believed to be responsible for the recently demonstratedpharmacological activity of the glands. It is proposed thatflaccid paralysis is induced in prey by envenomation with thissecretion during rasping, after soft parts have been exposedby an ‘anti-predator’ reaction to secretion fromthe hypobranchial gland of Nucella. The secretory vesicles ofboth types of gland cells in the acinous glands have heterogeneouscontents indicating that their secretions are complex. The majorcomponent in those of the mucous cells is an acid mucopolysaccharidetypical of a lubricant or releasing agent. The ciliated basalcells resemble typical enzyme-secreting cells and the majorconstituent of their secretion is a finely granular glycoprotein. (Received 8 January 1990; accepted 5 June 1990)     

小地老虎雄性附腺细微结构和功能及高温的影响

本文通过光镜、电镜和生化分析等方法,研究了小地老虎Agrotis ypsilon(Rottemberg)雄性附腺的细微结构和功能,结果表明：(1)雄性附腺是一对管状腺,基段粉红色,中段桔红色,端段乳白色。形态分化在蛹前期完成,分泌功能在羽化后4天进入旺盛期;(2)附腺细胞属蛋白质合成型,具有旺盛的合成蛋白质的能力,胞内含有致密的粗面内质网和游离核糖体颗粒,大量的分泌液泡均匀地分布在细胞质中;(3)顶浆分泌和局部分泌是腺体的二种主要分泌方式, 前者分泌的颗粒物为糖蛋白性质(Pas阳性),后者吩泌的网状物为非糖蛋白性质(Pas阴性),二者在腺腔内呈有规则的放射状排列“4”雄性附腺分泌物具有种的特异性,小地老虎、棉铃虫和粘虫等夜蛾科昆虫分泌物的蛋白电泳谱带存在明显的种间差异,高温(32℃)抑制了雄性附腺分泌某些蛋白质的能力,从而改变精液的成分。     

The Ultrastructure of Ion-Secreting and Non-Secreting Salt Glands of Limonium platyphyllum

The ultrastructure of salt glands in developing leaves of Limoniumplatyphyllum is described prior to exposure to 3% NaCl solution(with non-secreting glands) and after 4.5 and 18 h exposureto the salt solution. It is shown that in most glands, the transitionto active chloride transport was accompanied by the displacementof vacuoles toward the cell periphery and by the establishmentof plasmalemma contact sites with the tonoplast which appearedsimilar to gap junctions in animal epithelial cells. No evidencefor the exocytosis of vacuoles was found. It is suggested thatgland vacuoles may have a primary role in chloride secretionand that the tonoplast may be functionally asymmetrical, sothat the free part facing the hyaloplasm bears ion pumps, whereashighly permeable ion channels are active along the zone of contactwith the plasmalemma. It follows that the active step in chloridetransport in Limonium glands is the influx of ions into thevacuoles. Within the inner cup cells of the gland, vacuolescome into contact with the plasmalemma only at sites where thecell wall is adjacent to secretory and accessory cells. Suchan asymmetry appears to ensure the directed flux of ions intothis cell wall. Wall protuberances in the gland cells are rudimentaryand presumably not involved directly in NaCl secretion. Thenucleolus is activated during secretion and the frequency offree ribosomes is significantly increased, which is suggestiveof their involvement in the synthesis of membrane transportproteins. The ultrastructure of about one-third of the glandsremained unchanged in salt-treated leaves. Key words: Salt glands, ultrastructure, ion fluxes     

小地老虎雄蛾中胚层生殖道和附腺的细胞结构和分泌功能

通过光镜、电镜及组织化学等方法,研究了小地老虎生殖前期雄蛾中胚层生殖道和附腺的腺细胞结构和分泌功能,以及与精子形态和数量变化的关系,结果表明：(1)以缢缩位置、解剖形态、细胞结构、分泌方式、精子形态变化和数量变动为依据,将中胚层生殖道划分为修精囊、输精管、贮精囊、精包腺1～5段等8个区段;(2)中胚层生殖道和附腺具有相同的组织层次,自内向外分为单细胞上皮层、底膜、肌肉层和围膜等4层,但缺少表皮质内膜;(3)中胚层生殖道和附腺的腺细胞具有旺盛的合成和分泌蛋白质的能力,主要有内质网型和液泡型两种,前者有发达的粗面内质网和高尔基体,后者具有致密的核糖体和分泌泡;至少有4种分泌方式：即颗粒顶泌、液泡顶泌、胞质局泌和胞间分泌;修精囊、贮精囊、雄性附腺、精包腺1段的顶泌物为糖蛋白性质(PAS阳性)、局泌物为非糖蛋白性质(PAS阴性)。     

Development and Essential Oil Content of Secretory Glands of Sage (Salvia officinalis)

Scanning electron microscopy of sage (Salvia officinalis L.) leaves confirmed the presence of two basic types of glandular trichomes consisting of a capitate stalked form containing a multicellular stalk and surmounted by a unicellular secretory head, and a capitate sessile form containing a unicellular stalk and unicellular, or multicellular, secretory head. In the latter type, secretory activity and filling of the subcuticular cavity may begin at virtually any stage of the division cycle affording fully developed glands containing from one to twelve cells in the secretory head. Gas liquid chromatographic analysis of the oil content of the most numerous gland species (capitate stalked, capitate sessile with one and with eight secretory cells) indicated only minor quantitative differences in essential oil composition. Thus, each gland type is capable of producing the four major monoterpene families (p-menthanes, pinanes, bornanes and thujanes) characteristic of sage.     

Bracelet salt glands of the recretohalophyte Limonium bicolor: Distribution,morphology, and induction

Halophytes complete their life cycles in saline environments. The recretohalophyte Limonium bicolor has evolved a specialized salt secretory structure,the salt gland, which excretes Na⁺to avoid salt damage. Typical L. bicolor salt glands consist of 16 cells with four fluorescent foci and four secretory pores. Here, we describe a special type of salt gland at the base of the L. bicolor leaf petiole named bracelet salt glands due to their beaded-bracelet-like shape of blue auto-fluoresc...     

The Digestive Glands of Pinguicula: Structure and Cytochemistry

The digestive glands of the carnivorous genus Pinguicula havethree functional compartments, (a) a basal reservoir cell, (b)an intervening cell of endodermal character and (c) a groupof secretory head cells. The gland complex is derived from asingle epidermal initial. The reservoir cell, which is richin Cl^– ions, is highly turgid before discharge; it islinked by plasmodesmata to the surrounding epidermal cells,and is ensheathed by a pectin-rich inner wall layer. The endodermalcell is bounded by a Casparian strip to which the plasmalemmais tightly attached; it contains abundant storage lipid andnumerous mitochondria. The head cells of the developing glandhave labyrinthine radial walls of the transfer-cell type, theingrowths being composed of pectic polysaccharides. The boundingcuticle is discontinuous, although lacking well-formed pores.Mitochondria are numerous, with well-developed cristae; theplastids are large and ramifying, and invested by ribosomalendoplasmic reticulum. Dictyosomes are sparse, and where theyoccur, are associated with coated vesicles. Ribosomal endoplasmicreticulum is moderately abundant in the head cells, and so alsoare free ribosomes. Optical and electron microscopic localizationmethods indicate that the digestive enzymes are synthesizedin the head cells and transferred both into the vacuoles andinto the walls. There is no evidence of a granulocrine modeof secretion, and the transfer seems to be initially by directperfusion through the plasmalemma. During the final phase ofmaturation of the head cells they suffer a form of autolysis,vacuoles, cytoplasm and wall becoming confluent as all of themembranes of the cell undergo dissolution. The gland head isthus, in effect, simply a sac of enzymes at the time of theultimate discharge. Pinguicula, carnivorous plant, insectivorous plant, enzyme secretion, digestive gland     

The induction of energized configurational changes in plant mitochondria,in vivo

Configurational changes in the mitochondrial membranes of the salt gland ofTamarix aphylla, which are dependent on the biochemical state of the mitochondria, are demonstrated. In the energized state the cristae expand and become closely associated. There is also an increase in the density of the matrix and a formation of strands of material in the matrix and between the closely associated cristae membranes. The energized condition can be discharged by incubation in a medium containing 2,4-dinitrophenol and the mitochondria are comparable to those observed in glands fixed by typical methods for electron microscopy.These studies were supported in part by Grant GB-8199 (W.W.T.) from the National Science Foundation.     

CHARACTERISTICS OF SALTS SECRETED BY TAMARIX APHYLLA

The composition and concentration of salts secreted by the salt glands of Tamarix aphylla L. grown under controlled nutrient conditions were determined. Eight ions, Na, K, Mg, Ca, Cl, NO₃, HCO₃, and SO₄, constituted 99 % + of the dry weight of salts secreted by plants grown on half-strength Hoagland's solution. The divalent cations Mg and Ca accounted for most of the cations; HCO₃ comprised about 60 % of the anions. The micronutrients B, Mn, Cu, Zn, and Mo were present in enriched concentrations in the secretion. The composition of the secretions was highly dependent on the composition of the root environment. The predominating cation in the saline culture solutions was also the predominant cation secreted. The accompanying anion in the culture solution influences the cation composition of the secreted salt. The concentration of the salt gland secretion averaged 0.5n , a 50-fold increase in concentration over the nutrient solution in which the plants were grown.     

Translucent Glands and Secretory Canals in Hypericum perforatum L. (Hypericaceae): Morphological, Anatomical and Histochemical Studies During the Course of Ontogenesis

Hypericum perforatum L., traditionally used in folk medicineas a therapeutic plant, is today being evaluated for its antidepressantand antiretroviral activities. The species is characterizedby the presence of different types of secretory structure: translucentglands or cavities, black nodules and secretory canals. Theaim of this work was to characterize the translucent glandsand secretory canals in both the floral and vegetative parts,from morphological, anatomical and histochemical points of view.Translucent glands consist of a sub-epidermal cavity delimitedby two layers of cells. There are three types of secretory canal:type A, with a narrow lumen, and types B and C, both with awide lumen, but with different patterns of development. Histochemicaltests showed that all these structures contain alkaloids andlipids but not pectic-like substances and proteins. Tests forresins, essential oils and tannins gave different responsesin different parts of the plant. Copyright 2001 Annals of BotanyCompany Hypericum perforatum, St. John's wort, secretory structures, morphology, anatomy, histochemistry     

AN ULTRASTRUCTURAL STUDY OF THE GLAND OF LEIBLEIN OF MURICID AND NASSARIID NEOGASTROPODS IN RELATION TO FUNCTION, WITH A DISCUSSION ON ITS HOMOLOGIES IN OTHER CAENOGASTROPODS

The gland of Leiblein of the muricid Nucella lapillus and thenassariid Hinia reticulata has been examined by scanning andtransmission electron microscopy. The origin and functionalsignificance of its complex organization and its relationshipwith the rest of the mid-oesophagus in Nucella are discussed.It is absorptive as well as secretory, and a mechanism is proposedby which solute-rich fluids may enter the gland. Its epitheliumis composed of occasional mucous cells and two major cell types:ciliated cells engaged in protein metabolism and unciliatedcells responsible for uptake and storage of lipids and carbohydrates,both of which show evidence of pinocytotic uptake of solutesand intracellular digestion in lysosomes. Some enzyme activitypersists in the residual bodies they shed by apocrine secretion,but they remain intact in a mucous string until they reach thestomach. Preliminary ultrastructural examination indicates thatthe gland absorbs cadmium not only from the blood but also directlyfrom its lumen and that it may have the capacity to sequestera wide range of toxins. The same types of cell occur in Hiniain which their cyclical activity has been correlated with feeding.Similar cells have been identified in the oesophageal glandsof other prosobranchs. The foregut glands of carnivorous caenogastropodsare compared with the gland of Leiblein. There is an inversecorrelation between the role of the mid-oesophagus in digestionand absorption and the complexity of the stomach. (Received 16 August 2004; accepted 24 January 2005)     

FUNCTIONAL MORPHOLOGY OF THE RECTUM IN THE MARINE GASTROPOD LITTORINA SAXATILIS (OLIVI) (PROSOBRANCHIA:LITTORINOIDEA)

The ultrastructure of the rectum of the marine prosobranch gastropod,Littorina saxatilis suggests that it may have an additionalrole to the voiding of faecal pellets. It consists of two epitheliallayers, separated by a blood space. The inner epithelial layeris greatly folded and consists of metabolically highly activecells containing a wide variety of inclusions, and showing evidenceof secretory activity at their luminal surfaces. The outer epitheliumcontains a greater diversity of cell types, also with a largenumber of different inclusions present. Unlike some other prosobranchgastropods, a distinct rectal gland is absent in L. saxatilis.The entire rectal epithelium is glandular, and it appears thatthe rectal epithelial cells produce a number of secretions.This may indicate a role in absorption, the removal of materialfrom the blood, or the addition of a final covering to the faecalpellets. (Received 6 February 1989; accepted 6 March 1989)     

Studies on the Resin Glands of Azadirachta indica A. Juss. (Meliaceae)

The leafy shoots of Azadirachta indica have numerous, yellowresin glands, composed of a short stalk and sub-glandular tissuebeneath an epithelium-like 1-2-layered secretory tissue. Thefoot arises from the epidermis. The resin glands are derivedfrom a single papillate epidermal cell which functions as aresin gland initial. Histochemical localization using fluorescencemicroscopy confirmed the resinous nature of the secretion. Thegeneral structure of the glands shows similarity to extra-floralnectaries. Reports in the literature on the occurrence of extrafloralnectaries in Meliaceae should be confirmed by analysis of thesecretions if they are to be accepted. Azadirachta indica, resin glands, ontogeny, structure, secretion     

The Stimulation of Acid Phosphatase Activity in the Stalked Gland of Drosera rotundifolia

Localization of acid phosphatases (phosphomonoesterases II EC3.1.3.2 [EC] ) was studied in the secretory cells of stalked glandtissue of Drosera rotundifolia L. using a modified Gomori procedurewith p-nitrophenol phosphate (pNP) as substrate. In unstimulatedand 24 h stimulated tissue, some acid phosphatase activity waslocalized in vacuoles, cell wall regions and cuticular poresof only a few cells. Following stimulation for either 48, 72or 96 h, acid phosphatase activity was additionally observedin most gland cells within the nuclear envelope, endoplasmicreticulum and dictyosome cisternae and their associated vesicles,suggesting a de novo synthesis of acid phosphatases. Acid phosphatase, cytochemistry, Drosera rotundifolia, secretory cells