The chromosomal locations and linkage relationships of the structural genes for the prolamin storage proteins (secalins) of rye

Summary Rye secalins are a polymorphic mixture of polypeptides which are classified into four major groups. Previous studies have shown that the structural genes for two of the groups (the -secalins and 40K -secalins) are located on the short arm of chromosome 1R and those for a third group (the high molecular weight secalins) on the long arm of the same chromosome. Analysis of F₂ grain from crosses between inbred lines of S. cereale shows that the structural genes for the -secalins (designated Sec 1) and the high molecular weight secalins (designated Sec 3) are loosely linked (40.8 ±3.76% recombination, 57.4 ± 11.30 cM). Analysis of wheat rye addition lines shows that the structural genes for the 75K -secalins are present on chromosome 2R. This locus is provisionally designated Sec 2. These genes are probably derived from those for the 40K -secalins by duplication, divergence and translocation. Analysis of secalin fractions from wild species of rye shows that all contain 75K -secalins, indicating that the duplication and divergence, if not the translocation, occurred before speciation of the genus.     

Ontogeny of gonadotropin releasing hormone and gonadotropin immunoreactivity in brain and pituitary of normal and estrogen-treated guppies,Poecilia reticulata Peters

Summary Gonadotropin releasing hormone (GnRH) and gonadotropic hormone (GTH) were identified by immunohistochemistry in the brains and pituitaries of neonate, juvenile and adult guppies. GTH was present in some cells of the pars intermedia (pi) and proximal pars distalis (ppd) of all animals. GnRH was found in the perikarya of the nucleus olfactoretinalis. In the pituitaries of juvenile 30-day-old guppies, GnRH-immunoreactive cells existed in a juvenile pattern, whereas in adult animals GnRH was recognized in only a few cells. GnRH-immunoreactive fibers were seen in the pituitaries of animals that were 30 days or older. In adult guppies, the ventral and lateral ppd (the gonadotropic region) contained a dense network of GnRH-immunoreactive fibers. Pituitary cells staining for either GnRH or GTH were located in different places. After immunohistochemical double staining of adult pituitaries, none of the GnRH-immunoreactive cells were LH-immunoreactive, although both cell types were often found in close proximity. After 20 days or more of ethinylestradiol treatment, less immunoreactive GnRH was detected in the pituitary cells of juvenile guppies, and fewer animals exhibited the juvenile pattern of GnRH-immunoreactive pituitary cells, when compared with untreated controls. The results indicate that GnRH-immunoreactive pituitary cells in the guppy are distinct from gonadotropes and that these cells are involved in regulatory processes along the juvenile brain-pituitary-gonad axis.     

Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.     

Ultrastructure and immunolabeling of gonadotrops and thyrotrops in the pituitary of the African catfish,Clarias lazera

Summary Pituitaries of the African catfish (Clarias lazera) were studied with immunocytochemical methods, at the light-microscopic and ultrastructural levels, for the characterization and localization of gonadotropic and thyrotropic cells. Two immunostaining procedures with the use of different markers were carried out: (i) with peroxidase-antiperoxidase, (ii) with protein A-gold. In routinely stained sections for light microscopy two types of basophils were identified in the proximal pars distalis: (1) large, round, purple cells, and (2) small, angular, light-blue cells. Both types were immunolabeled with antibodies against Clarias ,-gonadotropin (GTH) and salmon G100-GTH. Only the large basophils were immunolabeled with anti-carp -GTH, whereas the small basophils were the only cells immunolabeled with anti-human thyrotropin beta subunit (anti-h TSH-). It was concluded that the large basophils represent the gonadotrops and the small basophils the thyrotrops. At the ultrastructural level the immunostaining of the GTH-cells was confined to three types of inclusions: (i) secretory vesicles, (ii) globules, and (iii) electron-dense, membrane-bound irregular masses. Especially the protein A- gold method, in combination with the use of a highly diluted homologous antiserum, resulted in a distinct localization of GTH. The presence of two types of nerve fibres, synaptically contacting the gonadotrops, is discussed with regard to the presence of a peptidergic (stimulatory) and an aminergic (inhibitory) control of GTH-secretion.Part of the results were presented as a poster at the IX^th conference of the European Society of Comparative Endocrinology, Jerusalem, August 1981, and published as an abstract (Peute et al. 1982)     

Erratum: Cloning and sequencing of the phycocyanin gene from Spirulina maxima and its evolutionary analysis

The genes were cloned for the two apoprotein subunits, and ,of phycocyanin from the cyanobacterium Spirulina maxima = Arthrospiramaxima) strain F3. The - and -subunit gene-coding regionscontain 489 bp and 519 bp, respectively. The -subunit gene is upstreamfrom the -subunit gene, with a 111-bp segment separating them.Similarities between the -subunits of S. maxima and nine othercyanobacteria were between 58% and 99%, as were those between the -subunits. The maximum similarity between the - and -subunits from S. maxima was 27%.     

Immunocytological localization of LH,FSH, TSH and their subunits in the pituitary of normal and anencephalic human fetuses

Summary Immunostaining with antisera to oLH, hCG, hLH, pLH, hFSH, hFSH, hTSH and bTSH was used to delineate the gonadotropic and thyrotropic cells of the human fetal anterior pituitary. Hypophyses from 29 normal fetuses, 3 newborn infants, and 5 totally ancencephalic fetuses were used. Several controls to check for the specificity of the immunocytological reaction were made.In normal fetuses, observations showed that: 1) the subunit was detected from the eighth week and throughout gestation without sex differences; 2) intact LH was detected during the third month, however, age and sex differences were observed during the fourth and fifth months; 3) intact FSH was detected in female fetuses from the beginning of the fourth month, a sex difference was observed; 4) LH and FSH were detected in the same cells; 5) the thyrotropic cells were detectable from 15 weeks of gestation and their number increased during gestation without sex difference; 6) at birth the gonadotropic cells were scarce and were located in the ventromedian zone of the anterior pituitary, while the thyrotropic cells remained numerous and were located in the dorsomedian zone.In anencephalic fetuses: 1) the subunit existed at each stage studied; 2) the reaction induced by anti-pLH and anti-hFSH sera was always very weak regardless of sex or age; 3) the thyrotropic cells were more numerous in comparison to the gonadotropic cells. These data are discussed in terms of the relationship of the hypophysiotropic hypothalamic factors to the appearance and evolution of the glycoprotein hormones and their subunits.     

Observations on the reduction of non-activated carboxylates by Clostridium formicoaceticum with carbon monoxide or formate and the influence of various viologens

Crude extracts or supernatants of broken cells of Clostridium formicoaceticum reduce unbranched, branched, saturated and unsaturated carboxylates at the expense of carbon monoxide to the corresponding alcohols. The presence of viologens with redox potentials varying from E ₀=-295 to-650 mV decreased the rate of propionate reduction. The more the propionate reduction was diminished the more formate was formed from carbon monoxide. The lowest propionate reduction and highest formate formation was observed with methylviologen. The carbon-carbon double bond of E-2-methyl-butenoate was only hydrogenated when a viologen was present. Formate as electron donor led only in the presence of viologens to the formation of propanol from propionate. The reduction of propionate at the expense of a reduced viologen can be followed in cuvettes. With respect to propionate Michaelis Menten behavior was observed. Experiments are described which lead to the assumption that the carboxylates are reduced in a non-activated form. That would be new type of biological reduction.Non-standard abbreviations glc Gas liquid chromatography - HPLC high performance liquid chromatography - RP reverse phase; Mediators (the figures in parenthesis of the mediators are redox potentials E ₀ in mV) - CAV²⁺ carbamoylmethylviologen, 1,1-carbamoyl-4,4-dipyridinium dication (E ₀=-296 mV) - BV²⁺ benzylviologen, 1,1-dibenzyl-4,4-dipyridinium dication (E ₀=-360 mV) - MV methylviologen, 1,1-dimethyl-4,4-dipyridinium-dication (E ₀=-444 mV) - DMDQ²⁺ dimethyldiquat, 4,4-dimethyl-2,2-dipyridino-1,1-ethylendication (E ₀=-514 mV) - TMV²⁺ tetramethylviologen, 1,1,4,4-tetramethyl-4,4-dipyridinium dication (E ₀=-550 mV) - PDQ²⁺ propyldiquat, 2,2-dipyridino-1,1-propenyl dication (E ₀=-550 mV) - DMPDQ²⁺ dimethylpropyldiquat, 4,4-dimethyl-2,2-dipyridino-1,1-propenyl dication (E ₀=-656 mV) - PN productivity number=mmol product (obtained by the uptake of one pair of electrons) x (biocatalyst (dry weight) kg)^-1×h^-1     

Histochemical evidence for granulosa steroids in follicle maturation in the African catfish,Clarias lazera

Summary The effects of carp pituitary suspension (CPS) and 11-desoxycorticosterone-acetate (DOCA) on 3-hydroxysteroid dehydrogenase (3-HSD) and glucose-6-phosphate dehydrogenase (G6PD) activity in the ovary of Clarias lazera are described. Strong 3-HSD and G6PD activities are localized in the stroma, of both control and treated fish. A single CPS injection stimulates 3-HSD activity in the granulosa of postvitellogenic, maturing and postovulatory follicles, but DOCA has no such effect on the postvitellogenic and maturing follicles, and only stimulates a weak response in the postovulatory ones.     

Inheritance and linkage relationships of glutamate oxaloacetate transaminase isoenzymes in apple

Summary Four zones of enzymatic activity for glutamate oxaloacetate transaminase (GOT) were found in apple tissue. A dimeric gene, GOT-1, determining the fastest migrating zone, was identified. Six alleles were found, including a near null allelle which produced detectable heterodimeric bands but not homodimeric bands. A marked deficit or absence of certain geno-types in all backcrosses and in some crosses between unrelated varieties was attributed to the close linkage (r=0.02±0.005) of GOT-1 with the incompatibility S locus. GOT-1 was also closely linked with the isocitrate dehydrogenase locus IDH-1 (0.03±0.01). Proposed incompatibility genotypes for four cultivars, and the linked GOT-1 alleles are Cox: S ₁ b/S ₂ d, Idared: S ₃ a/S ₄ c, Fiesta: S ₃ a/S ₂ d and Kent: S ₃ a/S ₁ b.The results reported in this paper are part of a PhD Thesis by the first author     

Dynamics of the cytoskeleton of epidermal cells in situ and in culture

Summary The cytoskeleton of primary tissue-culture cells from the epidermis of Xenopus laevis tadpoles was investigated by phase-contrast, immunofluorescence, and electron microscopy. The connection between the arrangement of different types of filaments and the mechanical properties of the epidermis is discussed. The bilayered epidermis attains stability from thick bundles of tonofilaments interconnecting the basal desmosomes. Twisting of tonofilaments around each other can explain the occurrence of elastic filamentous curls forming a meshwork braced between rows of small desmosomes in the apical region of the epidermis. Actin is arranged as a diffuse meshwork and sometimes forms bundles intermingling with tonofilament bundles. Surface membranes and rows of small desmosomes are delineated by actin and contain -actinin. Actin raises the tension for rounding and spreading of cells. Microtubules stabilize already well-developed lamellae.     

Cell multiplication and ultrastructure ofMicrasterias denticulata (Desmidiaceae) grown under salt stress

Cells ofMicrasterias denticulata Bréb. were kept in nutrient solution of high osmolality (salt stress) for four weeks. In a special cell multiplication test it was established that cell division is gradually inhibited at increasing salt concentrations and totally arrested at the highest concentration (26 mosm/kg). Recovery studies proved that even cells from the highest concentration range start dividing immediately after being placed in aqua bidest. thus indicating the full reversibility of the inhibiting effect. — Cells of the highest concentration range show marked ultrastructural changes. Besides an enormous accumulation of starch and oil bodies and a condensed appearance of the ground plasma, a reduction of mitochondria, ER and the Golgi-system is found. The most striking effect occurs on the vacuolar system which appears extremely reduced and condensed. The cell wall is thickened by the formation of an additional cell wall layer with a spongy electron microscopical appearance. Through the cell wall many droplets of a probably fat-like substance are excreted. — In summary, salt stress induces growth-inhibited akinete cells in the sense ofFritsch; these can be reactivated by decreasing the salt concentration. The salt-induced akinete state seems to be an ecological adaption to unfavourable conditions rather than a degeneration of the cells.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday.23. 12. 1988     

Functional and spectral characterization of the respiratory chain of Chloroflexus aurantiacus grown in the dark under oxygen-saturated conditions

In this paper we attempt a functional and spectral characterization of the membrane-bound cytochromes involved in respiratory electron transport by membranes from cells of Chloroflexus aurantiacus grown in the dark under oxygen saturated conditions. We conclude that the NADH-dependent respiration is carried out by a branched respiratory chain leading to two oxidases which differ in sensitivity to CN^- and CO. The two routes also show a different sensitivity to the ubiquinone analogue, HQNO, the pathway through the cytochrome c oxidase being fully blocked by 5 M HQNO, whereas the alternative one is insensitive to this inhibitor. The cytochrome c oxidase containing branch is composed by at least two c-type haems with E _m 7.0 of +130 and +270 mV ( bands at 550/553 nm and 549 nm, respectively), plus a b-type cytochrome with E _m 7.0 of +50 mV ( band at 561 nm). From this, and previous work, we conclude that respiratory and photosynthetic electron transport components are assembled together and function on a single undifferentiated plasma membrane.Abbreviations HQNO heptylhydroxy-quinoline-N-oxide - UHDBT undecyl-hydroxydioxobenthiazole - Q/b-c ubiquinol/cytochrome c oxidoreductase complex - BChl bacteriochlorophyll     

Voltage dependence of the basolateral membrane conductance in theAmphiuma collecting tubule

Summary The basolateral potassium conductance of cells of most epithelial cells plays an important role in the transcellular sodium transport inasmuch as the large negative equilibrium potential of potassium across this membrane contributes to the electrical driving force for Na⁺ across the apical membrane. In the present study, we have attempted to establish, theI-V curve of the basolateral membrane of theAmphiuma collecting tubule, a membrane shown to be K⁺ selective. TransepithelialI-V curves were obtained in short, isolated perfused collecting tubule segments. The shunt conductance was determined using amiloride to block the apical membrane Na⁺ conductance. In symmetrical solutions, the shuntI-V curve was linear (conductance: 2.2±0.3 mS·cm^–2). Transcellular current was calculated by subtracting the shunt current from the transepithelial current in the absence of amiloride. Using intracellular microelectrodes, it was then possible to measure the basolateral membrane potential simultaneously with the transcellular current. The basolateral conductance was found to be voltage dependent, being activated by hyperpolarization: conductance values at –30 and –80 mV were 3.6±1.0 and 6.6±1.0 mS·cm^–2, respectively. BasolateralI-V curves were thus clearly different from that predicted by the constant field model. These results indicate that the K⁺-selective basolateral conductance of an amphibian collecting tubule shows inward (anomalous) rectification. Considering the electrogenic nature basolateral Na–K-pump, this may account for coupling between pump-generated potential and basolateral K⁺ conductance.     

Morphometric evaluation of subcellular changes induced by in vivo TRH treatment in the pituitary gland of Rana perezi: Effects on prolactin and thyrotropic cells

Summary The effects of synthetic thyrotropin-releasing hormone on pituitary prolactin and thyrotropic cells were investigated in adult male Rana perezi (formerly Rana ridibunda) frogs. Animals were given daily injections of synthetic thyrotropin-releasing hormone into the dorsal lymph sac. Prolactin and thyrotropic cells were identified by the colloidal-gold method, using anti-human prolactin and anti-human--thyrotropin hormone as primary antisera. The stereological parameters of the rough endoplasmic reticulum, Golgi complex, and secretory granules of prolactin and thyrotropic cells were evaluated by ultrastructural morphometry (point-counting method). Thyrotropin-releasing hormone caused cytological changes in both cell-types which were consistent with increased synthesis and release of both prolactin and thryrotropin. These changes were still significant after 48 h treatment in the case of thyrotropic cells, while in prolactin cells the thyrotropin-releasing hormone increased the number of secretory granules. After 6 days, the cells resembled essentially those used as controls. These results indicate that thyrotropin-releasing hormone stimulates the synthesis and release of prolactin and thyrotropin, and that the response of each cell type to this hypothalamic stimulus follows a different time-course.This work has been supported by grants no. 2184-83 and PB 86-0095 from the Comisión Interministerial para la Ciencia y Tecnología, Spain     

Immunocytochemistry of gonadotropic cells and identification of cell types in ultrathin cryosections of the pituitary of the rainbow trout,Salmo gairdneri

Summary The most frequently occurring cell types in the pars distalis of the pituitary gland of the rainbow trout, (i) the lactotropic, (ii) the gonadotropic, and (iii) the somatotropic cells, were identified in cryosections. Their morphological characteristics were compared with those of Epon-embedded material. Cell location, cell form, position of the nucleus, arrangement of rough endoplasmic reticulum and sizes of secretory granules proved to be useful parameters for identification. The size distribution of secretory granules of corresponding cells in cryosections and Epon sections proved to be similar. Additionally, both the immunoferritin and the unlabeled antibody enzyme method were applied for the immunocytochemical labeling of gonadotropic hormone-producing cells in cryosections. Anti-salmon-GTH as well as anti-carp-GTH serum showed the presence of GTH in both the smaller and the larger granules of the classical GTH cells, but also produced a reaction in TSH cells. Labelling of TSH cells was absent when using anti--carp-GTH. Specificity of the reaction depended upon the degree of dilution of the anti-GTH serum. Results with dilutions of 14,000 and 18,000 in the unlabeled antibody enzyme method, and of 18,000 up to 132,000 in the immunoferritin technique were optimal. Acid phosphatase activity in the smaller granules was demonstrated by enzyme cytochemistry in Epon sections. The relationship of the presence of hormone in these granules is discussed. The high sensitivity of the immunocytochemical labeling procedure is discussed with respect to cryo-ultramicrotomy.     

An immunocytochemical study of the pituitary gland of the white seabream (Diplodus sargus)

The adenohypophysis of the white seabream (Diplodus sargus) was studied using histochemical and immunocytochemical techniques. The adenohypophysis was composed of rostral pars distalis, proximal pars distalis and pars intermedia. Prolactin (anti-chum salmon prolactin positive) and adrenocorticotropic (anti-human ACTH positive) cells were found in the rostral pars distalis. Prolactin cells were organized into follicles, while ACTH cells were arranged in cords around neurohypophyseal tissue branches that penetrated the rostral pars distalis. In the proximal pars distalis, somatotropic (anti-chum salmon and anti-gilthead seabream growth hormone positive), gonadotropic (anti-chum salmon -gonadotrophin II and anti-carp -gonadotrophin II positive, but anti-chum salmon -gonadotrophin I negative) and thyrotropic (anti-human -thyrotropin positive) cells were observed. Growth hormone cells were restricted to the dorsal and ventral part of the proximal pars distalis. They were clustered or surrounded the neurohypophyseal branches. Only one type of gonadotrophin cell was identified and they were clustered or isolated in the proximal pars distalis. Scattered groups of thyrotropin cells were located throughout the proximal pars distalis. In the pars intermedia somatolactin (anti-chum salmon and anti-gilthead seabream somatolactin positive) and melanotropic (anti--melanotropic hormone positive) cells were localized. In addition, gonadotrophin cells surrounded the pars intermedia or distributed evenly between somatolactin and melanotropic hormone cells. Somatolactin cells were periodic acid-Schiff negative and surrounded the neurohypophyseal branches intermingled with melanotropic cells. These cells were also immunoreactive to anti-human ACTH antiserum.     

Effects of cycloheximide on preprophase bands and prophase spindles in onion (Allium cepa L.) root tip cells

Summary Effects of cycloheximide (CHM) on preprophase bands (PPBs) of microtubules (MTs) and on prophase spindle MTs in root tip cells of onion (Allium cepa L.) were examined. When root tip cells were treated with 36 M CHM for 0.5–4 h, the population of cells with a PPB did not decrease markedly although the population of mitotic cells and that of prophase cells with a PPB gradually decreased to half of the control root tips. In prophase cells treated with 11 and 36 M CHM for 2 h, the width of the PPB was 1.4 times broader than that in the prophase PPB without CHM. Electron microscopic observation on the cross section of the PPB showed that the number of MTs and the distance between adjacent MTs in prophase PPBs treated with CHM were similar to those in the early developmental stage of PPBs without CHM. The bipolar spindle, that appeared in late prophase was not seen in prophase cells treated with 11 M or higher concentrations of CHM for 2 h. In order to examine differences of perinuclear MT arrangement between CHM treated and non-treated prophase cells, arrangement of perinuclear MTs was examined by confocal laser scanning microscopy. In control cells without CHM, MTs appeared on the nuclear surface with several branched or cross over type MT foci in the cytoplasm when broad PPB formation started. These MT foci were replaced by the aster type MT foci, from which several MTs radiated along the nuclear surface. The aster type MT foci gradually gathered to form a bipolar spindle. MTs connecting the spindle pole region and the PPB were seen in late prophase. In CHM-treated cells (11-360 M for 2 h), branched and cross over type MT foci were prominent, even in prophase cells with well condensed chromosomes. Neither linkages of MTs between the spindle pole region and the PPB nor aster type MT foci were seen. These observations showed that CHM prevents the bundling of MTs in the PPB and also inhibits the formation of aster type MT foci that is essential for bipolar spindle development.     

Further studies on the metabolism of gibberellins (GAs) A9, A20 and A29 in immature seeds of Pisum sativum cv. progress No. 9

Seed maturation of Pisum sativum cv. Progress No. 9 proceeds more slowly in winter than in summer even when the parent plants are grown in greenhouse conditions with light-and heat-supplementation. For parent plants grown under summer and winter conditions the metabolism of [³H]GA₉ in cultured seeds is qualitatively different in seeds of equivalent age and qualitatively the same in seeds of equivalent weight. 13-Hydroxylation of [³H]GA₉[³H]GA₂₀ is restricted to early stages of seed development. 2-Hydroxylation of [³H]GA₉2-OH-[³H]GA₉ has only been observed at a stage of development after endogenous GA₉ has accumulated. 2-OH-GA₉ has been shown to be endogenous to pea and is named GA₅₁. H₂-GA₃₁ and its conjugate have not been shown to be present in pea and may be induced metabolites of [³H]GA₉. The metabolism of GA₂₀GA₂₉ is used to illustrate a technique of feeding [²H][³H]GAs in order to distinguish a metabolite from the same endogenous compound. The in vitro conversion of [³H]GA₂₀[³H]GA₂₉, and the virtual non-metabolism of [³H]GA₂₉ have been confirmed for seeds in intact fruits. These results are discussed in relation to the apparent absence of conjugated GAs in mature pea seeds.Abbreviations GA_n gibberellin A_n - GC gas chromatography - GC-MS combined gas chromatography-mass spectrometry - GC-RC combined gas chromatography-radio counting - Me methyl ester - R_T etention time - SICM selected ion current monitoring - TLC thin layer chromatography - TMS trimethyl silyl ether The author is née Frydman     

Differential response to irradiation in offspring of freshwater and seawater substrains of Poecilia (Lebistes) reticulata peters in the “guppy male courtship activity test”

Summary An inbred strain (Istanbul) of guppies was divided into two substrains, one of which was maintained and bred in seawater. The offspring of irradiated animals of both substrains (1000 R X-rays to spermatogonia and oogonia of neonatal fish) were tested in a new gruppy male courtship activity test and compared with control groups. The postirradiation response in the seawater substrain was more intense than in the freshwater substrain.Dedicated to Prof.Dr.Dr.h.c.mult. Curt Kosswig on the occasion of his 75th birthday     

Die Homologie des Perigons der Zingiberaceen Ein Beitrag zur Morphologie und Phylogenie des Monokotylen-Perigons

Nicolaia elatior is used as an example to demonstrate that the mucronate tepals ofZingiberaceae correspond to hypsophylls (bracts) consisting of a leaf sheath and a rudimentary Oberblatt (= leaf petiole + lamina) represented by the mucro. Evidence for this interpretation is furnished by all available criteria: leaf sequence (exhibiting a complete continuum of forms from foliage leaves over cata- and hypsophylls to the tepals), nervature, and ontogeny.The present conception is compared with the well-founded thesis ofLeinfellner that the perigone ofLiliaceae is derived from the androecium. The different morphological status of the perigone in both families is not regarded as the result of different phylogenetic origin, but as a manifestation of morphogenetic transgressions from one phyllome category to an adjacent one: In theLiliaceae the perigone is under a strong morphogenetic influence of the androecium, and therefore displays staminal characters, in theZingiberaceae it is under the dominating influence of the extrafloral region, and thus appears as a hypsophyllous structure. If this assumption of a morphologically oscillating perigone is correct, it will be fundamentally impossible to demonstrate unequivocally the phylogenetic origin of the monocotyledonous perigone.

Im wissenschaftlichen Werk Prof. Dr.Walter Leinfellners steht an erster Stelle die Morphologie der Blütenorgane. Als sein dankbarer Schüler möchte ich ihm aus Anlaß seines 70. Geburtstages die folgende Studie zu einem Thema zueignen, das ihn wie mich gleichermaßen angesprochen hat und schon Gegenstand der Forschungsarbeit des Jubilars war: die Homologie des Monokotylen-Perigons.