Sulla presenza di batteri nei vari organi delle piante superiori

Summary

In close agreement with Schanderl's findings it is shown that bacterial cultures may be obtained from the most different parts of non-Leguminous plants representing several families of higher plants. These bacteria, isolated from parts of higher plants, do not seem to be identical with the ones inducing nodules in Leguminous plants.     

Studio Anatomico delle Reazioni Indotte dalla Decapitazione Combinata a 2,4-D in Turioni di Asparagus Officinalis L

Summary

1) Young stems of Asparagus officinalis L., from 12 to 46 cm. in length, were decapitated just below the shoot apex and 2,4-D was applied to the cut surface in concentrations 0,1% to 2% by weight in lanolin paste. Decapitated Asparagus stems treated with lanolin only served as controls. A total of 50 stems, of which 10 controls, were investigated.

2) Apart from the sprouting of lateral buds in two plants, no other macroscopical or histological reaction was noticed in the control material. Following treatment with 2,4-D, on the contrary, the following gross responses were evidently seen

a) Bending reaction (figs. 2, 3, 5). This was found to occur in 13 plants, on the second to fourth day since decapitation and at a distance of 1 to 5 cm. from the cut surface. Only in one case was the bending so pronounced as to bring about a complete change in polarity of the upper portion of the stem;

b) Tumor formation. In 8 plants, 7 of which had been treated with doses 1% or 2% of 2,4-D, a swelling appeared just below the surface of decapitation. Due to a difference in cell elongation between the cells of the fundamental parenchyma and those of the cortex, the cut surface took, in a few days, a spoon-like appearance (fig. 10). In two of the 8 plants a tumor-like swelling was noted at some distance from decapitation (fig. 11);

c) Unbalanced elongation in fasciated stems. This brought about the bending towards the cut surface of the more elongated portion in fasciated stems (fig. 15);

d) Longitudinal splits in fasciated stems. (figs. 12, 13). Longitudinal splits were noticed in some of the fasciated stems, which appeared also affected by a very strong gummosis;

e) Survival of decapitated stems. 2,4-D treatment clearly increases the survival of decapitated stems, the maximum duration of survival being 19 days in controls and 30 to 33 days in some stems treated with 1% or 2% phyto-hormone;

f) Sprouting of lateral buds (figs. 4, 5). The frequency of this phenomenon in 2,4-D treated material is not higher as compared with that of controls. However, the treatment seems to induce some auxinlike responses in lateral branches.

3) Concerning the histological reactions, the following can be said

a) No mitosis stimulation is induced neither by wounding alone nor by wounding plus 2,4-D in any portion of the Asparagus stem;

b) radial cell elongation of cortical cells and, in some cases, of pericycle cells (Borgstrom's «transverse reaction») is responsible for both sub-terminal tumors and the two tumor-like swellings of the type reported in fig. 11 (fig. 20 for histological details). Differential elongation in different portions of the stem is responsible for some of the gross responses referred to above;

c) extensive lignification and suberization of parenchyma and, sometimes, epidermal cells occur in 2,4-D treated material. Lignification begins, on the 12th to the 15th day since decapitation, in the cells of the pericycle and fundamental parenchyma surrounding the outermost bundles and gradually spreads centripetally reaching, in extreme cases, some portions of the pith (fig. 24). In these same cases, the lignification process (which is generally present in the first 2 or 3 cm. below the cut surface) may extend as far as 7 cm. below the surface of decapitation. The lignification process appears not to be spred evenly in the stem, being sometimes localized in one or more large areas (fig. 18) and expressing itself in highest degree in zones near the divergence of leaf traces (fig. 16). Lignification of cortical parenchyma and of isolated groups of epidermal cells occurs in a later stage, being concomitant with some suberization process in other cells of the same region of the stem. Photographs of different patterns of both suberization and lignification processes in the layers from epidermis to outermost bundles are reported in figs. 26 to 31, all taken from material treated with 2% 2,4-D. The lignification process takes place according to the well-known scheme of «vascular differentiation» (Sinnot e Bloch 1945);

d) gummosis is very common in 2,4-D treated material. The various stages of gummosis in the different tissues of the stem have been described and special attention has been paid to the extensive formation of lysigenous spaces, following cell degeneration (figs. 32 to 37).

4) In discussing the results of the present investigation, the point is stressed that by experimental means it has been possible to induce in Asparagus some patterns of tissue differentiation and distribution which are to be found in other species of Monocotyledons. After taking into special consideration the actually available data on «vascular differentiation», a twofold effect of 2,4-D on this process is assumed to have taken place, namely: a) favouring influence on cell wall lignification and b) prolongation of survival, probably bringing about a kind of «aging» of tissues. This prolongation of survival seems also to have been a determining factor in the occurrence of the strong gummosis noticed.     

La partecipazione del mesenchima alla morfogenesi delle ghiandole. Ricerche sperimentali sulla ghiandola di Harder

Zusammenfassung Durch frühzeitige Zerstörung der ganzen primären Augenblase, bzw. des oberflächlichen Abschnittes der Augenanlage mit dem anliegenden Ektoderm, wurde beim Hühnerembryo die Entwicklung des ektodermalen Bestandteiles derHarderschen Drüse verhindert. Trotzdem legte sich der mesenchymale Bestandteil der Drüse an normaler Stelle an und entwickelte sich normal bis zum Ausschlüpfen; nur war die ausschließlich aus Mesenchym zusammengesetzte Anlage etwas kleiner als die normale Drüse. Vom 10. Tage der Bebrütung ab erscheint bei den operierten Embryonen der bindegewebige Bestandteil der Drüse als eine scharf konturierte, von den anliegenden Geweben gesonderte Masse von länglicher Form. Vom 16. Tage der Bebrütung ab dringen in die bindegewebige Masse kleine runde, stark granulierte Wanderzellen (vielleicht Makrophagen) ein; dasselbe wurde in der normalen Drüse beobachtet.Dadurch wird das Bestehen einer relativen Unabhängigkeit zwischen den beiden Bestandteilen derHarderschen Drüse, dem epithelialen und dem mesenchymalen Anteil, bewiesen; die Vermutung liegt also nahe, daß eine gewisse Unabhängigkeit in der Determination der beiden bestehe.     

Ricerche sul decorso delle infezioni sperimentali da Dermtatofiti in rapporte a un eventuale stato di iperrecettivita' provocata

Riassunto L'A. ha eseguito una serie di ricerche sperimentali sulla cavia consistenti in inoculazioni ripetute per molti giorni per via epicutanea di Tric. Gyps. Ast., Ach. Quinq., Micr. Lan., in reinoculazioni omologhe e crociate ripetute, inoculazioni in animali pretrattati con iniezioni di tricofitina. L'A ha constatato che 1 ripetere le inoeulazioni porta al costituirsi di alterazioni cutanee a carattere intensamente infiammatorio anziehè portare ad un'attenuarsi progressivo delle lesioni. Nelle reinoculazioni omologhe e crociate le lesioni insorte invece di tendere ad una rapida risoluzione si stabiliscono e durano a lungo. Il pretrattamento con tricofitina in animali, che poi ricevono un'unica inoculazione, influenza nettamente l'aspetto della micosi che insorge; ciò avviene in aumento o in diminuzione a seconda della quantità di antigene iniettato. Riportandosi dopo queste acquisizioni alle lesioni umane del tipo infiammatorio l'A. prospetta l'ipotesi ehe esse siano legate ad inoculazioni multiple e le forme torpide, a parità di micete, ad un'unica inoculazione.

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Summary The A. has attendet to a series of experimental researches on the guinea pig, consisting of inoculations of Tric. Gyps. Ast., Ach. Quinq., Micr. Lan., repeated during many days, by epidermidal way, of reinoculations repeated homologous and crossed and of inoculations is animals preventively treated with trichophitin injections. The A. has ascertained that repetition of the inoculations brings about alterations of a nature intensely inflammatory, instead of bringing about the progressive decrease of the lesions. In the homologous and crossed reinoculations, the originated lesions, instead of showing a tendency to a rapid resolution, settle down and last long. The preventive to a rapid resolution, settle down and last long. The preventive treatment with trichophitin in animals that will aftewards be inoculated only once, affect clearly the aspect of the rising mycosis that will be weaker or stronger, according to the quantity of the injected trichophitin. Alter these acquisitions, the A. referring to the human lesions of an inflammatory nature, expresses the hipothesis that they may be connected with multiple inoculations and that the torpid forms, with he same quantity of fungus, may be connected with one single inoculation.

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Zusammenfassung Der V. hat eine Versuchsreihe an dem Meerschweinchen durchgeführt. Diese bestand aus viele Tage durch wiederholten Einimpflungen von Tric. Gyps. Ast., Ach. Quinq., Micr. Lan., auf dem epidermoidalen Wege, aus homologen und gekreuzten wiederholten Wiedereinimpfungen und aus Einimpfungen an mit Trichophiteimspritzungen vorbehandelten Tieren. Der V. hat festgestellt dafz die Wiederholung der Einimpfungen zur Entstehung hochentzündlicher hautartiger Veränderungen führt statt zu einer Verminderung der fortschreitenden Verletzungen zu führen. In den homologen und gekrezten Wiedereinimpfungen lassen sich die aufgetretenen Verletzungen nieder und dauern lange, statt zu einer schnellen Entscheidung zu neigen. Die Vorbehandlung mit Trichophitin an Tieren, die nachher eine einzige Einimpfung bekommen werden, beëinflüsst deutlich das Aussehen der auftretenden Mycosis, die je nach der Menge an eingespritztem Trichophitin stärker oder schwächer sein wird. Nach diesen Erwerben, bezieht sich der V. auf die entzündlichen Menschenverletzungen und nimmt an dafs sie mit vielfachen Einimpfungen und die torpiden Formen, bei gleichen Pilze, mit einer einzigen Einimpfungen verbinden sind.

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Résumé L'A. a fait une serie de recherches experimentales sur le cobaye, consistent dans des inoculations de Tric. Gyps. Ast., Ach. Quinq., Micr. Lan., répétées pendant plusieurs jours, par la voie épidermique, dan des réinoculations homologiques et croisées répétées et des inoculations dans des animaux traités précedentement avec des injections de tricophytine. L'A a constaté che la répétition des inoculations cause des alterations cutanées d'une nature fortement inflammatoire. Dans les réinoculations homologues et croisées, les lésions surgies au lieu d'aboutir à une rapide résolution, se fixent et durent longuement. Le traitement préventif avec de la tricophitine dans des animaux qui seront inoculés une seule fois, influence clairement l'aspect de la naissante mycose, qui sera plus faible ou plus forte, selon la quantitè des fongus injecté. Aprés ces acquisitions l'A. se référant aux lesions humaines d'une nature inflammatoire, exprime l'hypothèse qu'elles soient en rapport avec des inoculations multiples et que les formes atones, avec le même fongus, soient en rapport avec une unique inoculation.

     

Sulla respirazione dell'apparato radicale delle piante coltivate

Riassunto

A conferma di quanto s'era supposto, la respirazione profonda è apparsa processo fisiologico assai comune. Infatti, essa è stata accerta'a — spesso anche in fasi e periodi diversi del ciclo vitale della stessa pianta — in tutte le specie saggiate (circa 40 riferibili a 16 famiglie).

Nelle piante legnose, il processo respiratorio profondo è risultato della stessa natura che nelle specie erbacee.

Il processo respiratorio profondo e il processo respiratorio superficiale ipogco acquistano valori e significati diversi sia dal lato fisiologico che agronomico secondo la forma coltivata (specie, individuo), le condizioni termiche e la natura del mezzo asfittico del suolo. Per tanto, vuoi nelle piante erbacee che legnose coltivate, è dato osservare una grande variabilità d'adattamento i cui estremi incidono sulle specie che normalmente vivono coll'apparato radicale in terreno idropico cioè in mezzo asfittico costituito da eccesso d'acqua immota e, per contro, sulle specie sensibili — fino a un certo punto — a qualunque comune mezzo asfittico del suolo e però provviste di sistema di radici relativamente superficiale. Le une e le altre sembrano collegate da forme le quali sviluppano comunemente il sistema radicale in terreno libero da acqua stagnante, profondo, permeabile ma tuttavia asfittico negli orizzonti meno superficial — e pi[ugrave] erti — del suolo per atmosfera inerte e per eccesso di CO₂.

A entrambi i processi respiratori testè rilevati si allacciano interessanti problemi agronomici riguardanti tra l'altro i lavori di preparazione del suolo eccezionalmente energici particolarmente nei riflessi che questi possono avere a cagione d'una temporanea maggiore aereazione indotta.     

Ricerche anatomiche e sperimentali sull'innervazione delle vene cave.

Zusammenfassung Man kann in der Hohlvenenwand des Meerschweinchens 2 Nervenplexus unterscheiden: einen oberflächlichen und einen Plexus internus. Zahlreiche, in Schlingen gelegte receptorische Endapparate charakterisieren den oberflächlichen Plexus. Diese außen liegenden Endapparate stehen mit dicken markhaltigen Fasern in Verbindung.Solche Endapparate fehlen im Plexus internus, sind aber auch in der kranialen Hohlvene nicht zu finden.Der Plexus internus ist engmaschig und enthält zahlreiche marklose und dünne markhaltige Fasern. Die Fasern bilden ein Terminalreticulum.Die Nervengeflechte der Hohlvenenwand enthalten keine Ganglienzellen.Der rechte Phrenicus beteiligt sich an der Bildung der Nervengeflechte in der Hohlvenenwand durch zwei oder drei Ästchen, welche sich im oberflächlichen Plexus erschöpfen (Meerschweinchen).Nach Exstirpation des rechten Phrenicus entarten die dicken markhaltigen Fasern und ihre Endigungen.Die linksseitigen Phrenicusektomie und eine doppelseitige Vagotomie haben keinen Einfluß auf die Nervenstrukturen der caudalen Hohlvene.Diese Ergebnisse bestätigen, daß der Nervus phrenicus einen viscerosensiblen Bestandteil besitzt, welcher von cerebrospinalen Fasern gebildet wird.     

Saggio di inoculazioni incrociate di funghi patogeni tra animali e piante

Summary Common frogs (Rana edulis) were inoculated intraperitoneally with the following fungi: 1) pathogenic for man and animals:Coccidioides immitis, Gilchristia dermatitidis, Paracoccidioides brasiliensis, Phialophora verrucosa andSporotrichum beurmanni; 2) pathogenic for man and plants:Sporotrichum poae; 3) pathogenic for plants:Botrytis cinerea. The fungi of the group 1) (and, to a lesser extent, the group 2) produced a localized granuloma, without (or almost without) dissemination, with a reduced, aspecific reaction, chiefly in the gastro-duodenal plica. The species of the group 3) is not pathogenic at all.On the contrary, for broad bean young plants (and, to a lesser extent, castor bean plants) the fungi of the group 1) were not pathogenic, while the fungus of the group 3) was fully pathogenic.S. poae appears to be of moderate pathogenicity; less pathogenic has beenS. beurmanni.

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Un riassunto parziale di queste prove è stato presentato dai due Autori al Third International Congress for Microbiology, New York, 2–9 September 1939 (Sect. VI, Paper No. 5) e pubblicato nel 1940 (Redaelli P., Ciferri R. eBaldacci Blastomycosis, Sporotrichosis and Coccidioidal granuloma on animals and plants. Mycopathologia,II, 322–326 1940. Le esperienze furono quindi proseguite dai due Autori seniores, secondo una più vasta scala di ricerche, sinchè il sopraggiungere della guerra e le difficoltà di lavoro inerenti obbligarono a sospenderle. Ancora nell'intento di onorare la memoria del compianto amico e collaboratore Prof.P. Redaelli, ci decidiamo a dare alla luce queste note, ora pubblicate in esteso, completate con le prove eseguite dopo la presentazione della nota suddetta. R. C.     

Fenomeni di regressione cellulare in piante succulente

Riassunto

Sono studiati i fenomeni citologici che permettono, a foglie di piante succulente, di seccare, all'inizio della stagione sfavorevole, come foglie di igrofite. Detti fenomeni vengono identificati con processi di denaturazione dei complessi muco-proteici plasmatici.     

Osservazioni microbiologiche sui nettarii di piante alpine secondo contributo

This study, based on inter-simple sequence repeats in 14 populations of Linaria capraria, shows that genetic diversity at the species level is 0.21 and represents 58% of total variance, whereas the level of intrapopulational genetic diversity is 0.07 and represents 42% of total variance. Gene flow is absent between populations from the same island. On the basis of analysis of molecular variance, three centers of genetic diversity were found: Elba and Pianosa, Montecristo, and Capraia; these correspond to the group of islands that remained isolated during the Würm marine regression. A mean proportion of species-level diversity resides among populations, so we hypothesize that the species has a mixed reproductive system that lies somewhere between obligate outcrossing and obligate selfing. The most genetically diverse populations live in natural and well-isolated rocky habitats that seem to have no particular intervention requirements for conservation but the entire system of populations of this endemic species should be preserved.     

Effetto della rimozione dei fiori sulla crescita delle piante e sul contenuto in leghemoglobina dei tubercoli radicali di pisello e fava

Abstract

Observations on vegetative growth and leghemoglobin contents of root nodules of pea and bean plants after flower bud removal. — These studies found their origin in the papers by MATTIROLO (1899) on the effect of the removal of flowers as they formed in bean plants; he observed that deflowering resulted in extraordinary plant growth, stem branching and flower buds formation as well as in a delayed root nodule senescence. In the light of modern knowledge of the leghemoglobin role in symbiotic nitrogen fixation, the aim of the present research was to ascertain any possible relation between flower bud removal and haeme pigment contents in the root nodules. The experiments were carried out during two growing seasons (1966 and 1970) using Vicia faba L. cv. Regina and Pisum sativum L. cv. Senatore during 1966 and cv. Vittoria in 1970. In both control and test plants the seasonal trends of average plant height, fresh and dry weight of vegetative portions, fresh and dry weight of root system, fresh weight of nodules, root nodule leghemoglobin concentration and total leghemoglobin content per plant, were determined. The data obtained are quoted in Table 2 and reported in Figures 1, 2, and 3. The removal of flower buds caused in both species: an increased plant growth, a marked stem branching, a longer blooming period, an increased flower number, an increased root nodule number and a certain delay in root nodule reabsorption. Deflowering did not significantly extend — at least in the species studied — life span (senescence was delayed only of one week). On the basis of these and of other Authors' results, we conclude that deflowering may actually delay senescence; the size of this delay, however, depends on the plant species considered and is fairly negligible both in pea and bean. The different effects of deflowering and of preventing floral induction on life span extension, are discussed, and these facts lead to consider floral induction as the onset of a chain of processes leading annual plants toward senescence in a more or less delayable, but definitive way. After having stressed the generally accepted importance of leghemoglobin concentration as an index of nodule nitrogen fixing ability, a correlation between biomass increase of test plants and number and total weight increase of root nodules, is put in evidence. No correlation between test plant biomass and the leghemoglobin concentration in root nodules, was however observed. Leghemoglobin concentration in root nodules is known to change in connection with various factors depending either on host plants and on Rhizobium strains and also in connection with several environmental conditions. Any prevented flower onset (ROPONEN and VIRTANEN, 1968) and deflowering (our data) however exerted no significant influence. The effects of flower bud removal were therefore the following: increased stem, leaf and root weights and increased root nodule number; no difference between control and test plants was however observed as regards size and leghemoglobin concentration of root nodules and hence probably no difference as regards their nitrogen fixing ability.     

Alterazioni indotte da infezioni sistemiche di Peronospora tabacina Adam in piante di Tabacco

Injuries induced by systemic infections with Peronospora tabacina Adam in tobacco plants The author describes the macroscopic and microscopic symptoms (particularly at the base of the stem) after systemic infections of Peronospora tabacina in resistant and susceptible tobacco plants. The mycelium of the pathogen could be demonstrated in the vessels of stem and leaves; stem and leaves furthermore showed deformities and necrosis. The relationships between the two groups of symptoms and the causes for the absence of conidial formation in resistant plants (which in other respects displayed the symptoms described) are discussed.     

Purification and characterization of Ricinus communis invertase

An invertase from Ricinus communis leaves was purified 4,400-fold. The preparation was homogeneous by criteria of gel electrophoresis, gel permeation, adsorption, and ionic exchange chromatography. One optimum pH at 3.5 was observed with crude invertase; however, purified preparations showed two optima, at pH 3.5 and 5.5. Addition of bovine serum albumin restored one maximum at pH 3.5 and elicited a 30% activation of the invertase. The effect was caused by many other proteins and by heparin, dextran sulfate, and polyvinylpyrrolidone. Fructose, fructose 1,6-diphosphate, maleic, trans-aconitic, malic, and ascorbic acids were simple competitive inhibitors of the purified enzyme. Glucose was a noncompetitive inhibitor. The activation by proteins suppressed these inhibitory effects. The minimum concentration of activator necessary to reach the maximal activation or "point of optimal activation" was always reached at a concentration of 1 X 10(-6) M, independently of the nature of the activator, when 8.6 X 10(-12) mol of enzyme were used. Apparent molecular weight determinations of the enzyme in the presence and absence of activator and molecular weight determinations based on determinations of the point of optimal activation suggested that the purified enzyme is a heptamer (Mr of 77,900, Stokes radius 32 A, frictional ration f/fo 1.1, partial specific volume 0.749 ml/g) and that the activated form is a trimer consisting of two enzyme subunits and one activator molecule. The activation was lost by dilution of the trimer. The enzyme subunit, as isolated by gel filtration in the presence of sodium dodecyl sulfate (Mr 11,000) was inactive but quickly regained activity upon removal of sodium dodecyl sulfate.     

Osservazioni istoanatomiche e sperimentali sulla innervazione dell'esofago di alcuni mammiferi

Zusammenfassung Die Versuche wurden ausgeführt, um weitere Beiträge zur Morphologie der Vagusfasern in der Speiseröhre zu liefern und zwecks Analyse der neurosynaptischen Verhältnisse zwischen Vagus und Sympathicus. In Speiseröhren von kleinen Säugetieren gelang es, die Verzweigungen des Vagus bis zu deren Endausbreitung zu verfolgen. Es wurden Kontrollen mit morpho-experimentellen Versuchen von Vagotomie ausgeführt.In den Ästen des Vagus der Speiseröhre befinden sich: Parasympathische präganglionäre Fasern, gemischte Fasern (heteromorphe: präganglionäre und motorische Fasern), sensitive Fasern und sehr dünne Fasern des Orthosympathicus.Viele präganglionäre Fasern breiten sich in mehr oder weniger ausgedehnten retikulären Bildungen (präneuronodales Retikulum) aus, bevor sie zu dem Ganglion, für welches sie bestimmt sind, gelangen. Im Ganglion platten sich einige präganglionäre Fasern ab und werden blattförmig. Andere wieder verbreitern sich zu fibrillären Bildungen retikulärer Struktur. In Präparaten mit feinerer Imprägnation bilden die präganglionären Fasern des Vagus keine synaptischen, perizellulären-Apparate des klassischen Typus sondern breiten sich in ein überaus dünnes Retikulum (terminalreticolo vagale pregangliare) im Ganglion aus.Dieses Retikulum umhüllt nicht bloß die nervösen Zellen, sondern breitet sich über alle Teile des Ganglions aus. Die als motorisch erkennbaren Fasern des Vagus liefern alle motorischen Endigungen, die traubenförmigen einbegriffen. Ich habe besondere, charakteristische, motorische, knäuelförmige Endapparate bemerkt. Diese und auch jene als Endbüschel (Lawrentjew) benannten Bildungen können ultraterminalen Fasern, die sich in gewöhnlichen Plättchen ausdehnen, den Ursprung geben oder das Ende traubenförmiger Ausdehnungen darstellen.Die gemischten Fasern (heteromorphe: präganglionäre und motorische) sind in überwiegender Weise motorische Vagusfasern, die einen kollateralen Ast liefern, der sich entweder auf die alleinstehenden Ganglienzellen ausdehnt oder im Ganglion sich mit den intraganglionären Fasern vermischt.Die rezeptorischen Fasern des Vagus bilden die Schlingenterritorien (Stöhr, Harting) oder die knäuelförmigen Bildungen von Greving. Manchmal schließen sich den sensitiven Vagusfasern zahlreiche, sehr dünne, wahrscheinlich metasympathische Fasern an.Ein Teil des metasympathischen Anteiles bildet einen Komplex von Fasern oder kleinen Strängen, welche die präganglionären, motorischen, gemischten und sensitiven Bestandteile des Vagus begleiten; diese metasympathischen Fasern bilden insbesondere in der Nähe der Ganglien sehr feine Retikula in enger Verbindung mit den parasympathischen Elementen.Im distalen Teil der Speiseröhre ist der sympathische Bestandteil überwiegend; es finden sich hier kleine Ringe oder kleine knöpfchenartige Bildungen, die von den motorischen Fasern des Vagus ausgehen, an dem glatten Muskelgewebe vor, es finden sich außerdem einige Nervenzellen mit perizellulären Apparaten, die jedoch von den obengenannten präganglionären Vagusendigungen verschieden und wahrscheinlich sympathischer Natur sind. Die anatomischen Eigenheiten im distalen Teil der Speiseröhre stellen wahrscheinlich die morphologische Grundlage für den Automatismus jenes Teiles der Speiseröhre dar.     

Nuove ricerche sperimentali nei trapianti di abbozzi diTriton suRana esculenta

Riassunto Un embrione diRana esculenta, allo stadio di bottone caudale, viene sottoposto a ripetuti trapianti di vescicole ottiche diTriton cristatus, su uno o su ambedue i fianchi, a diretto contatto con la massa vitellina ventrale (Fig. 1, A —a).CiÒ fatto e quando i trapianti hanno attecchito, viene trapiantata in sede cefalica e previa asportazione dell'abbozzo corrispondente, una vescicola ottica di un embrione diTriton (Fig. 1, A —b). L'altra vescicola ottica dello stesso embrione diTriton viene trapiantata, sempre in sede cefalica e previa asportazione dell'abbozzo corrispondente, in un altro embrione diRana, allo stesso stadio del precedente, ma che non ha subito trapianti ventrali (Fig. 1, B —b).Tali operazioni vengono ripetute su moite coppie di embrioni diRana.I reperti istologici di cui alle Figg. 2A, 3A, 4A, 5A illustrano i vari gradi di sviluppo e di differenziamento della vescicola ottica diTriton trapiantata in sede cefalica negli embrioni diRana che hanno subito i trapianti ventrali.Al contrario, negli embrioni diRana che non hanno subito tali trapianti ventrali, gli abbozzi diTriton posti in sede cefalica vanno in rapida distruzione, cosa questa già ben nota dalla letteratura ed ulteriormente illustrata dai preparati istologici di cui alle Figg. 2B, 3B, 4B, 5B.Queste osservazioni vengono interpetrate alla luce della teoria delCotronei relativa al ruolo del vitello nei fenomeni di incompatibilità embrionale che si verificano nei trapianti di Urodeli su alcuni Anuri.     

Reazioni di natura auxinica ed effetti rizogeni in Allium Cepa L.

Abstract

The biotic vectors for pollen and seed dispersal are compared in respect to their task. The type of rewards as well as the attracting mechanisms for pollinators and animals responsible for seed dispersal are listed. The rise of deception mechanisms (false advertisements) from seduction mechanisms are described.     

Identification of a rabbit sperm autoantigen as a Ricinus communis I receptor

The isolated rabbit sperm plasma membrane autoantigen RSA-1 has been identified as a receptor for the lectin, Ricinus communis I (RCA). Using purified RSA-1 labeled with¹²⁵ I, the autoantigen was shown to bind to RCA affinity columns and the eluted fraction bound to specific anti-RSA-1 alloantiserum immunoadsorbent columns.