Ontogenesis of Tannin-containing Coenocytes in Sambucus racemosa L.: III. The Mature Coenocyte

Mature tannin-containing coenocytes as long as the whole internodeare present in Sambucus racemosa, the longest being 32.8 cm.The shape of their nuclei and the structure of their chromatindiffer from those in adjacent parenchyma cells, whilst the cytoplasmalso differs both in electron density and in organelle fine-structure.In the seventh internode there are symptoms of nuclear and cytoplasmicdegeneration and loss of plastid and mitochondrial membranes. Tannin coenocyte, pith, Sambucus racemosa, cell structure, differentiation     

Ontogenesis of Tannin Coenocytes in Sambucus racemosa L. II. Mother Tannin Cells

Tannin coenocytes develop from mononucleate tannin mother cells.The process occurs within the whole of the first (youngest)internode and its development can be divided into three stages.In stage I the MTC is isodiametric and similar to the surroundingcells of the flank meristem, being present in the ninth celllayer from the apex surface. The nucleus becomes lanceolateand elongates, and large cytoplasmic vacuoles appear. A twofoldelongation of both the cell and nucleus continues in the secondstage, the cell-nucleus ratio indicating that it is due to theenlarged vacuole, which pushes a thin layer of cytoplasm closeto the cell wall. In this layer of cytoplasm dilated ER cisternaoccur together with small and large vacuoles, a fusion of thevacuoles increasing their volume. Such cells are diploid inspite of larger nuclear volume and rough structure of its chromatin. Sambucus racemosa L., tannin cells, development, ontogenesis     

The Internode of Sambucus racemosa L. Originates from a Single Cell Layer

The internodes of Sambucus racemosa L. shoot apices originatefrom a single layer of cells in which mononucleate mother tannincells are present. The mother tannin cells increase in lengthand differentiate together with the internodal growth. Sambucus racemosa L., shoot apices, internode, mother tannin cells, tannin coenocytes     

Localization of Phenolic Compounds in Tannin-secreting Cells from Sambucus racemosa L. Shoots

The localization of phenolic compounds was investigated in twokinds of idioblastic tannin cells: (1) mononucleate tannin cellsclose to the promeristem in which they are initiated, and comparedwith the surrounding tissue, and (2) the very long coenocytes(i.e. almost as long as the whole internode of Sambucus) andproducing large amounts of phenolics. One likely pathway forthe appearance of these compounds in the central vacuole ispostulated from their localization: phenolic precursors occuroutside the ER cisternae and enter the interior of parts ofthe ER cisternae which undergo fragmentation and dilatation.Many small vacuoles so formed fuse and lead to the formationof a large central vacuole. Phenolic compounds, tannin cells, idioblasts, Sambucus racemosa L., shoots     

Fine Structural Details of Tannin Accumulations in Non-Dividing Cambial Cells

The fine structure of autumn cambial cells of Aesculus hippocastanumand Populus x euramericana reveals the presence of electron-densebodies, other than lipids, in both the cytoplasm and vacuoles.These deposits are identified as tannins following a cytochemicaltest with ferrous sulphate. Small tannin bodies associated withthe strands of ER and inside small vesicles are often evidentin the cytoplasm. The cytoplasmic tannins are deposited intovacuoles by fusion of the tannin-containing vesicles with thetonoplast. The positive reaction of tannin inclusions with periodicacid-thiocarbohydrazide-silver proteinate suggests their polysaccharidicnature. The observations support the role of ER in tannin synthesisand deposition into the central vacuole. Aesculus hippocastanum, Populus x euramericana, cambial cells, tannin, vacuoles     

Cell division in caffeine-induced binucleate protonemal cells ofAdiantum. I. Asynchronous mitosis of two nuclei in a single cell

Coordination of karyokinesis of two nuclei in individual filamentous binucleate cells of the fern,Adiantum capillus-veneris was investigated. To induce binucleate cells, the protonemata were treated with caffeine, which is known as an inhibitor of plant cytokinesis, during the first synchronous division of cells that was induced by blue light (BL). The next synchronous division of cells in the resultant binucleate cells was analysed. In most cases, the two nuclei were associated with each other and were located in the apical region of the long protonemal cells (approximately 400–600 μm in length, 20 μm in width). In some cells, one nucleus was located in the apical region and the other was located in the middle of the cylinderical region. In such cells, karyokinesis of the apical nucleus preceded that of the basal nucleus, even though karyokinesis of associated nuclei progressed synchronously. Mitotic binucleate cells were centrifuged in order to gather two dissociated heterophasic nuclei. Progression of karyokinesis in the re-associated nuclei became coordinated within 1 h in most cells. These results suggest that mitosis-regulating factor(s) may diffuse to only limited distances inAdiantum protonemata.     

Nuclear and Cell Sizes in Different Regions of Root Meristems of Zea mays L.

Nuclear volumes and cell areas were determined for seven regionsof the meristem of roots of Zea mays. Roots were fixed in 10per cent neutral buffered formalin, in 3 per cent glutaraldehydeor in acetic acid/alcohol; they were prepared as sections oralls were teased apart. Mean volumes of interphase nuclei weresimilar in all regions of the root except the vascular tissueof the stele. Mean nuclear volumes and the overall range ofvolumes were similar in sub-populations of cells with differentproportions of G¹, S and G² cells, e.g. in row I of root capinitials, whose cells lack a G¹ phase, and in quiescent centrecells, which are mainly in G¹. Nuclear volume does not appearto be closely correlated with DNA content. Nuclear volumes covereda 6 to 12-fold range within a meristem and even within specificregions, in which cells are part of the same cell lineages,there was a 4- to 9-fold range. Nuclear volumes were comparedin sister cells in rows I and II of the root cap initials. In10 per cent of the pairs, sister nuclei had identical volumes;the other pain had different volumes and mean difference was68 µm³. Mechanisms by which this variability could begenerated are discussed, particularly asymmetry, at mitoses,of factors that regulate nuclear growth. Zea mays L., nuclear volume, cell size, root mcristem, DNA content, mitosis     

Isolation and characterization of a new non-toxic two-chain ribosome-inactivating protein from fruits of elder (Sambucus nigra L.)

Sambucus (Caprifoliaceae) species contain nigrin b and ebulinI, which are two-chain ribosomeinactivating proteins (RIPs)belonging to a new type of RIPS which are non-toxic to miceand cultured human cells. In this work the presence in fruitsof elder (S. nigra L.) of a new non-toxic type 2 RIP (nigrinf) that co-exists with a lectin known as SNA IV is described.Nigrin f strongly inhibited protein synthesis in mammalian,but not in plant, ribosomes, promoting the depurination of sensitiveribosomes and thus allowing the release of the RIP diagnosticRNA fragment. Nigrin f is composed of two dissimilar subunitslinked by disulphide bridges with apparent M_r values of 31 600and 26 300. The N-terminal amino acid sequence revealed closehomology of the catalytic A chain with type 1 RIPs, especiallythose from Cucurbitaceae, and the B chain with several lectinspreviously isolated from Sambucus species. Nigrin f was nottoxic to mice when injected intraperitoneally up to 2 mg kg^–1.In addition, NHC human cells were also insensitive to nigrinf up to 60 µg ml^–1. Anti-nigrin b rabbit polyclonalantibodies reacted with nigrin f, indicating that nigrin b andnigrin f are proteins with similar structures. Key words: Sambucus nigra, elder fruits, nigrin f, ribosomeinactivating protein, characterization     

Divisione Eterotipica in Cellule Somatiche di Sambucus Ebulus L.

Summary

The Author has studied the evolution of the somatic cells constituting the basal portion of the style-tissue in Sambucus Ebulus L. Simulating a sporogenous tissue, these cells undergo an usual heterotypic division with formation of bivalents and binucleate cells (two haploid nuclei). No cell-wall formation was observed in any case. During the degeneration of this sporogenous-like tissue, occuring soon after the anthesis, a fusion of nuclei in some cells was observed.     

Tissue-Dependent Expression of the Rice wx+ Gene Promoter in Transgenic Rice and Petunia

The waxy (wx) locus, which controls the amylose synthesis, isknown to be expressed specifically in the endosperm and pollen.To study the tissue-specific regulation of the wx⁺ gene, weintroduced a fusion gene that consisted of the upstream sequenceof the wx⁺ gene and the gene for rß-glucuronidase(GUS) into cells of rice (Oryza sativa L.) and petunia (Petuniahybrida L.). GUS activity was examined in the regenerated transgenicrice and petunia plants. In transgenic rice, the upstream sequenceof the wx⁺ gene was sufficient to direct the tissue-specificexpression of GUS in the endosperm and pollen, and the controlof expression was quantitative. By contrast, in transgenic petunia,the same fusion gene was expressed in pollen but not in theendosperm. These results suggest that the putative cis-actingelements that direct pollen-specific expression are common toor similar in both monocotyledonous and dicotyledonous plants,whereas ciy-elements responsible for the endosperm-specificexpression of the rice wx⁺ gene do not function in petunia,in which development of the endosperm differs from that in rice. ⁴Present address: Division of Biological Sciences, GraduateSchool of Science, Hokkaido University, Kita-ku, Sapporo, 060Japan     

An Autoradiographic Study of Bacterial DNA in Lycopersicon esculentum

³H-DNA from Escherichia coli has been fed to cut shoots of Lycopersiconesculentum. Autoradiographic studies have shown the bacterialDNA to be localized in the nuclei, plastids, and mitochondriaof cells in the phloem, cambium, parenchyma, collenchyma, andepidermis. Two populations of cells were detectable, namely, those withnuclei in which the ³H-DNA was localized, and those which failedto incorporate ³H-DNA into their nuclei. This may, in part,be due to the degree of availability of the DNA in these tissues,cambium, parenchyma, and collenchyma.     

Condensed Tannin Formation by Agrobacterium rhizogenes Transformed Root and Shoot Organ Cultures of Lotus corniculatus

Root cultures of Lotus corniculatus L. cv. Leo transformed withAgrobacterium rhizogenes (C58Cl-pRi15834) grew rapidly in liquidmedium when cultured in the dark and produced large numbersof shoots when illuminated. The shoots, which could be regeneratedto produce fertile plants, were maintained in liquid mediumas shoot-organ cultures The accumulation and cellular distribution of condensed tanninswas determined during the growth of these root and shoot organcultures and in primary callus from non-transformed explants.Root and shoot cultures predominantly accumulated insolublepolymeric tannins which yielded both cyanidin and delphinidinon hydrolysis at ratios equivalent to control plants. Methanol-solublevanillin-positive compounds were isolated but no free oligomericproanthocyanidins, monomeric flavans or dihydroflavonols weredetected in these extracts. Condensed tannin accumulation waslinearly related to root growth and had a similar spatial distributionin ‘tannin’ cells in roots and leaves as comparedto control plants. Tannin-containing cells were absent frommeristematic cells of the root tip and root/shoot interface.Primary callus cultures failed to accumulate condensed tanninson media containing auxins, and exogenously supplied auxinswere found to inhibit tannin accumulation by transformed rootand shoot cultures Key words: Lotus corniculatus, Agrobacterium rhizogenes, hairy roots, condensed tannins, shoot and root cultures.     

The Induced Resistance Response of Carrot Root Slices to Heat-killed Conidia and Cell-free Germination Fluid of Botrytis cinerea Pers. ex Pers.: 2. Nuclear Migration, Nucleolar Volume and Uptake of Tritiated Uracil

Sixty-eight per cent of nuclei in the cells of the upper fourlayers of carrot slices treated with heat-killed conidia ofBotrytis cinerea for 6 h followed by inoculation with live sporesfor 18 h, migrated to the cell face nearest to the treated surface,compared with 46 per cent in cells of control slices showinga wound-healing response only. Nucleolar volumes in the surfacecell layers of control slices increased from a mean of 1.0 µm³to 3.8 µm³ over 24 h, and in ‘induced’ slicesto 7.28 µm³. Using a 40 min pulse of [5–³H]uracil,there was an increase within 15 h of slicing in the number oflabelled nuclei in cells from control slices undergoing healing.Within 8 h after treatment of slice surfaces with heat-killedconidia, there was an accelerated incorporation of label into‘nuclear’ RNA. Slices from roots cold-stored for12 months failed to show an induction response and nucleolarvolumes did not increase more than in control slices. Theseresults are discussed in relation to active defence mechanismsin plant tissue. Botrytis cinerea, carrot, induced resistance, nuclear migration, nucleolar volume, RNA incorporation     

Late Transplanting and the Yield of Phaseolus vulgaris L.

The prediction that very high seed yields of dry beans (Phaseolusvulgaris L.) would be produced by the delayed transplantingof large plants has been tested in a factorial experiment withfour dates of transplanting and eight plant populations. Therewere significant differences in yield between transplantingdates and between population densities, and there was a significantdate-density interaction. At low plant densities (up to about30 plants m^–2) the three transplanted treatments yieldedless than the hand-sown controls, and late transplanting yieldedless than early. At the highest density the situation was reversed;all three transplanted treatments out-yielded the controls andlate transplanting tended to out-yield plants transplanted early.The biggest yield was 340 g seed m^–2 from a transplantedcrop grown at 35 plants m^–2. The data on yield fitted a modified rectangular hyperbola ofthe form where y is yield per unit area, p is the number of plants perunit area, t is the number of days between sowing and transplanting,and B_o, n, m, and p are arbitrary parameters. This equationaccounted for 91 per cent of the variation in yield with t andp. It is suggested that late transplanting had adverse effects,due to transplanting ‘shock’ and which were mostmarked at low plant densities; and beneficial effects, ascribableto an effect on plant ‘plasticity’, which were mostmarked at high plant densities. Possible physiological mechanismsof these effects are discussed. Phaseolus vulgaris, yield, density, transplanting     

Plant Chromatin Replicated in the Absence of Protein Synthesis

The aim of the present work is to detect possible differencesin the chromatin of plants replicated in the absence of proteinsynthesis. The kinetics of nuclease digestion in Allium cepa L., evaluatedafter making the cells permeable, was faster for the chromatinof meristem cells replicated in the presence of 1.0 µgml^–1 cycloheximide than in control cells. In order to have a synchronous population in the meristems,cells were labelled as binucleate by a short treatment with5.0 mM caffeine. Treated cells failed to increase both theircontent in dense chromatin and intranuclear histones. Thesefacts suggest that chromatin replicated in the presence of cycloheximidedid not incorporate histones and was unable to be integratedinto dense chromatin patches. Key words: Allium cepa L., Chromatin replication, Protein synthesis     

Calcium Movement, Graviresponsiveness and the Structure of Columella Cells and Columella Tissues in Roots of Allium cepa L.

Roots of Allium cepa L. cv. Yellow are differentially responsiveto gravity. Long (e.g. 40 mm) roots are strongly graviresponsive,while short (e.g. 4 mm) roots are minimally responsive to gravity.Although columella cells of graviresponsive roots are largerthan those of nongraviresponsive roots, they partition theirvolumes to cellular organelles similarly. The movement of amyloplastsand nuclei in columella cells of horizontally-oriented rootscorrelates positively with the onset of gravicurvature. Furthermore,there is no significant difference in the rates of organellarredistribution when graviresponsive and nongraviresponsive rootsare oriented horizontally. The more pronounced graviresponsivenessof longer roots correlates positively with (1) their caps being9.6 times more voluminous, (2) their columella tissues being42 times more voluminous, (3) their caps having 15 times morecolumella cells, and (4) their columella tissues having relativevolumes 4·4 times larger than those of shorter, nongraviresponsiveroots. Graviresponsive roots that are oriented horizontallyare characterized by a strongly polar movement of ⁴⁵Ca²⁺ acrossthe root tip from the upper to the lower side, while similarlyoriented nongraviresponsive roots exhibit only a minimal polartransport of ⁴⁵Ca²⁺. These results indicate that the differentialgraviresponsiveness of roots of A. cepa is probably not dueto either (1) ultrastructural differences in their columellacells, or (2) differences in the rates of organellar redistributionwhen roots are oriented horizontally. Rather, these resultsindicate that graviresponsiveness may require an extensive columellatissue, which, in turn, may be necessary for polar movementof ⁴⁵Ca²⁺ across the root tip. Allium cepa, onion, root, columella tissue, columella cell, gravitropism, calcium, ultrastructure     

Studies on the control of cell division in a green alga, Ankistrodesmus gracilis (Chlorococcales) III. Induction synchrony with controlled division patterns

When stagnant cells of Ankistrodesmus gracilis obtained froma standard culture were inoculated into the basal medium atcell densities lower than 1.0 ? 10⁷ cells/ml, cell proliferationoccurred stepwise at time intervals of about 30 hr. At a densityof 5.5 ? 10⁴cells/ml, the increase in cell number per step wasabout 2.7-fold. When inoculated into a glutamine medium thetime interval was 24 hr, and the average increase of cell numberwas about 4-fold. When cells were preincubated at about 5.0? 10⁵ cells per ml in the basal medium for 30 hr, then transferredinto a glutamine or arginine medium at about 7.0 ? 10⁶ cells/ml,synchronous division occurred about 18 hr later with binaryfission or about 33 hr later with multiple fission, respectively. (Received May 16, 1979; )     

Determination of Lignin and Tannin Contents of Cowpea Seed Coats

Tannins in the seed coats of cowpea cultivars interfere withthe determination of lignin by the acetyl bromide method butthe tannins can be removed by extraction with acetone:water(70:30) allowing a direct determination on the residue. Furthermore,the difference between the absorbance values determined by theacetyl bromide method before and after the removal of tanninscan be used as a measure of tannin content in cowpea seed coats.Copyright1995, 1999 Academic Press Cowpea, Vigna unguiculata, lignin, tannin, acetyl bromide     

In Vitro Culture of Hermaphrodite Floral Buds of Cucumis melo L.: Microsporogenesis and Ovary Formation

A method has been described by which floral buds of hermaphroditemelons isolated at various stages from archesporium to preleptotenein the pollen mother cells (PMC) can be grown through to pollen-grainformation in culture. Floral buds cultured for this period ina medium with thymidine-methyl-³H (³H-T) showed incorporationof label into the nuclei of tapetal cells and PMCs. The labelincorporated into the PMC was probably due to pre-meiotic DNAsyn-thesis. In other tissues of the floral buds, ³H-T incorporationproceeded through meiosis. Metabolic and environmental factorsinvolved in normal differentiation of the microsporogenous tissueof floral buds cultured in vitro are discussed.     

Cytology of Saprolegnia diclina Humphrey and S. terrestris Cookson ex Seymour in Relation to Congenital Oospore Abortion

In oogonia of Saprolegnia terrestris some nuclei completed twoconsecutive divisions to form small gamete nuclei, others wererestituted at intermediate division stages. Possible multiplechromosome associations were seen in some late prophase figuresof the first division. Seven to eight chromatin bodies werepresent in pro-metaphase figures. All nuclei except a smallnumber of gamete nuclei were broken down prior to formationof oospheres. Antheridial nuclei either completed divisionsto form small, gamete nuclei or were restituted to form large,torus-shaped nuclei. In oogonia of S. diclina, nuclei enteredprophase but no subsequent division stages were seen. Torus-shapednuclei, but not gamete nuclei, were seen in antheridia. Oosporenuclei of both S. terrestris and S. diclina varied both in size(about 5, 10 or 50–100 µm³) and number (0, 1 or2); 7.5 per cent of oospores of S. terrestris and 54 per centof oospores of S. diclina contained no nucleus or one smallnucleus only. The oospore abortion rate was 7.3 per cent inS. terrestris and 50.4 per cent in S. diclina. Oomycetes, Saprolegnia diclina Humphrey, Saprolegnia terrestris Cookson ex Seymour, cytology, oospores, abortion