Morfogenesi in espianti caulinari di Aucuba japonica Thunb. coltivati in vitro

Abstract

Morphogenesis in caulinar fragments of Aucuba japonica Thunb. in vitro. — Caulinar fragments of Aucuba japonica Thunb. are grown in vitro in different media. They show an obvious polarity; in fact only the basal section surface shows a vigorous proliferation and is able to form roots. When this surface emerges it gives rise to a green luxuriant callus; when the same surface is immersed it forms a protuberance in the shape of crateriform invaginations. Our histological studies indicate not only the connection between new proliferations and the pre-existent vascular tissues, but also the areas where the pseudothalli originate. The changes in the cortex and the central cylinder which are caused by the in vitro cultures were observed.     

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.     

Nuove ricerche sull'orientamento e il senso del tempo di Arctosa perita (Latr.) (Araneae lycosidae)

Zusammenfassung Die Uferspinne Arctosa perita (Latr.) verfügt über einen astronomischen Orientierungsmechanismus, durch den die Tiere imstande sind, wenn sie auf dem Wasser ausgesetzt werden, in der Richtung nach dem Ufer zu fliehen. Die Spinnen orientieren sich auf Grund des Sonnenstandes und des polarisierten Himmelslichtes und haben die Fähigkeit, die Tageszeit einzukalkulieren (Papi 1955b und c).Wenn eine Gruppe von Tieren gefangengehalten wird, dann nimmt bei den Fluchtversuchen die Streuung der Fluchtrichtungen zu. Dabei ist die Streuung der gesamten Fluchtversuche — wenigstens während der ersten 16 Tage — statistisch nicht verschieden, ob die Tiere nun a) in den natürlichen Belichtungs- und Temperaturschwankungen, b) im Dauerdunkel und in den Temperaturschwankungen oder c) im Finstern unter konstanter Temperatur gehalten werden. Was die Genauigkeit der Richtungsorientierung betrifft, so bleibt, trotz der stärkeren Streuung, die durchschnittliche Fluchtrichtung bei Gruppe a) bis zu 21 Tage lang korrekt, während sie bei den Gruppen b) und c) von der theoretischen Richtung immer mehr abweicht.Tiere, die im Finstern unter konstanter Temperatur gefangengehalten werden, orientieren sich bezüglich einer unbeweglichen Lampe bei verschiedenen Tageszeiten ungefähr so, wie wenn sie die Sonne wäre.Exemplare, die 3 Tage lang einem gegen den natürlichen Tag um 6 Std verschobenen Belichtungsrhythmus ausgesetzt werden, nehmen Orientierungswinkel an, die zur Zeit ihres künstlichen Tages korrekt wären.Ein innerer Tagesrhythmus (innere Uhr) regelt die Abweichung des Orientierungswinkels der Tiere. Im Laufe des Tages ändert sich der Orientierungswinkel nicht mit einer konstanten Geschwindigkeit, sondern mit einer solchen, die die Azimutgeschwindigkeit der Sonne auszugleichen sucht.Wenn die Tiere einige Stunden bei einer Temperatur von 4–5°C oder in 2°C gehalten werden, dann orientieren sie sich so, wie es einige Stunden vorher korrekt wäre. Der Gang der inneren Uhr kann also durch sehr niedrige Temperaturen verzögert oder gestoppt werden.Unter experimentellen Bedingungen können die Tiere in 8–10 Tagen neue Fluchtrichtungen erlernen.In der Besprechung werden die Resultate mit jenen verglichen, die bei anderen, einer astronomischen Orientierung fähigen Tieren erhalten wurden.

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Dedicato al Prof. Karl von Frisch in occasione del suo 70 compleanno.     

Ulteriori ricerche sulla germinazione di Cercis siliquastrum L. Azione dell'acido gibberellico e ruolo dell'endosperma nel fenomeno della dormienza

Abstract

Further research on the germination of Cercis siliquastrum L. Effect of gibberellic acid (GA₃) and role of endosperm in dormancy.—In order to locate the causes of the dormancy in Cercis siliquastrum L., researches have been carried out also on non-scarified seeds without integument, as well as on isolated embryos.

We have noted that gibberellic acid can substitute the cold treatment to interrupt the dormancy and we have also investigated the optimal concentrations.

The results we have obtained do not show the inhibition to be located in the integument and point out a determinant role of the endosperm.

Histological investigations are being carried out to study better the possible occurrence of a mechanical restraint imposed by the albumen on the non-dormant embryo.     

Isolamento di Schizomiceti cellulositici,Attinomiceti, Eumiceti dall' intestino delle Termiti e ricerche sulla attivita' cellulositica degli Attinomiceti

Riassunto Gli AA. sono riusciti ad isolare, per la prima volta, Schizomiceti cellulositici del genere Cytophaga ed Attinomiceti del genere Actinomyces, dall'intestino delle Termiti. Sono altresí isolate alcune specie fungine, come era già noto. Gli Attinomiceti isolati non dimostrano di possedera capacità di attaccare la cellulosa, analogamente a quanto accade per altri ceppi di diversa provenienza degli stessi microrganismi.Gli AA. confrontano e discutono i loro resultati con quelli di altri AA. tendenti ad attribuire ai Protozoi simbionti delle Termiti una attività cellulositica, che ad essi non sembra sufficientemente provata. Gli AA. ritengono che tale attività si debba, invece, attribuire ai Batteri simbionti dei Protozoi e a quelli aderenti alle pareti dell'intestino delle Termiti stesse.

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Summary From the intestinal apparatus of the Termites were isolated, for the first time, cellulositic bacteria of the genus Cytophaga, in addition to ray-fungi of the genus Actinomyces and species of true fungi previously known. The cellulositic activity of Actinomyces has not been, instead, experimentally demostrated.The results obtained are discussed in relation to the presumed cellulositic activity of Protozoa symbiotic of the Termite ants.

     

Osservazioni sulla microflora fungina di ceppaie di abete bianco

Abstract

Mycoflora of Silver fir (Abies alba Mill.) stumps. - This work is a first contribution to the knowledge of the mycoflora colonizing Silver fir (Abies alba Mill.) stumps in Italy.

Autochthonous fungal species were isolated from the wood of A. alba stumps from three different sites in the Tuscan Apennines.

Frequency values for the isolated species and taxonomic groups were calculated.

Deuteromycetes (57–82.5%) occurred more frequently than basidiomycetes (5–36%), phycomycetes (0.7–11.6%) and ascomycetes (0–1%). The most common genera were found to be: Aleurodiscus, Penicillium, Phellinus, Phialophora, Scytalidium, Sistotrema and Trichoderma.

An effective method of isolation from wood is also described.     

Forme Nuove di Arisarum Vulgare Targ. Tozz

Riassunto

L'autore, facendo delle ricerche sulla variabilità individuale nel numero dei fiori maschili e femminili dell'Arisarum vulgare, ha trovato alcuni casi teratologici e identificato e descritto le seguenti forme nuove: A. viridescens, A. Negrii, A. Pampaninii, A. Passerinii, A. Rovestii.     

Osservazioni sulla secrezione delle ghiandole sottomandibolare e sottolinguale di embrione di topo,in condizioni normali e in cultura in vitro

Riassunto E' stata studiata l'istogenesi e l'istochimica della ghiandola sottomandibolare e sottolinguale di embrione di topo, in condizioni di sviluppo normale e in cultura organotipica in vitro. In condizioni normali l'attività secretrice diviene dimostrabile con mezzi istochimici al 16 giorno di gestazione, come materiale intracellulare. La secrezione presenta fino dall'inizio reazione positiva ai metodi del PAS e di Hale, ed è colorabile col blu alcian. Al 17 giorno compaiono fra le due ghiandole differenze nell'aspetto morfologico del secreto, nell'intensità delle suddette reazioni istochimiche, e nel comportamento rispetto al blu di toluidina che dopo solfatazione dà colorazione metacromatica nella sottolinguale, ma non nella sottomandibolare. Ciò indica che il componente polisaccaridico del secreto ha caratteristiche un po' diverse nelle due ghiandole.Sono state eseguite culture in vitro di ghiandole al 13 giorno di gestazione, su un coagulo di plasma e di estratto embrionale di pollo. Al momento dell'espianto, esse sono all'inizio della loro differenziazione, e sono formate ciascuna da un cordoncino epiteliale e da una gemma solida, entro una comune capsula mesenchimale. Il processo di ramificazione si svolge più lentamente che in vivo, ma la secrezione compare alla stessa età totale. Le ghiandole si sono sviluppate in vitro per 10 giorni e le loro caratteristiche istochimiche sono apparse eguali a quelle che si osservano in condizioni normali di sviluppo.

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Summary Histogenesis and histochemistry of submandibular and sublingual glands of mouse embryo were studied both during normal development and in vitro. In normal conditions secretory activity becomes detectable by histochemical methods at the 16th day of gestation as intracellular material. From the start, secretion shows a positive reaction to the PAS and Hale's method, and stains with alcian blue. At the 17th day differences may be shown between the two glands in the morphological features of the secretion, in the intensity of the above said histochemical reactions, and in the behaviour towards toluidine blue, which after sulfation gives metachromatic staining in the sublingual, but not in the submandibular gland. This indicates that the polysaccharidic component of the secretion has different characters in the two glands.Cultures in vitro were made of glands at the 13th day of gestation, on a clot of chicken plasma and embryo extract. At explantation time, they are just beginning their differentiation, and both consist of an epithelial cord and a solid bud, contained in a common mesenchymal capsule. The ramification process goes on at a slower rate in vitro than in vivo, but secretion appears at the same total age. The glands developed in vitro for 10 days and their histochemical features appeared to be comparable to those which were observed in normal developmental conditions.

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Lavoro eseguito coi mezzi forniti da contratti di ricerca dell'U.S.A.E.C. (NYO-3355-10) e dell'Euratom (043-65-1 BIO I) e con un contributo del C.N.R.     

Sulle cause determinanti la formazione di tumori in ibridi di Nicotiana. Prime ricerche sierologiche

Abstract

PRELIMINARY SEROLOGICAL RESEARCHES ON MECHANISM OF TUMOR INDUCTION IN NICOTIANA HYBRIDS. According to GOODSPEED'S phyletic scheme, based on a cytogenetic evidence, both Nicotiana rustica and N. paniculata should be assigned to the sub-genus Rustica, while N. langsdorffiii and N. sanderae fit with the sub-genus Petunioides. Indeed the fact that genetical tumors are produced by the hybrids of these species only when the parents belong to different sub-genera, seems to support GOODSPEED'S views, just as KOSTOFF'S hypothesis of tumor production as a consequence of uncongeniality and incompatibility of parent's protein set, receives by this scheme a valid support.

Immunological research work has been carried out to test the possible affinities of the protein sets of the four Nicotiana species. It was observed that the protein set of N. paniculata is more similar to the protein set of N. langsdorffiii — a species included in a different sub-genus and whose hybrids with. N. paniculata bear tumors — than to the one of N. rustica, a species included in the same sub-genus and whose hybrids with N. paniculata never bear tumors. These studies are still in progress.     

Early ontogeny of vascular cambium II.Aucuba japonica andWeigela coraeensis

InAucuba andWeigela the six vascular bundles distributed as a hexagon become connected tangentially by meristematic cells into a procambial cylinder in the early stage. In the tangential view, the procambial cylinder shows a rather homogeneous structure. InAucuba, some cells of the procambium elongate in a relatively earlier stage and the rest also elongate during subsequent stages. All of these cells have tapering end walls. Then some long cells divide transversely and form two systems in the vascular meristem, one made up of long cells and the other of short ones. The long cells become the fusiform initials and the short cells, the ray initials. InWeigela, the homogeneous procambium is organized in the later stages into two systems, one of long cells and the other of short cells in axial files. Most of the long cells have tapering end walls and the short cells transverse end walls. Some of the short cells elongate to intrude between adjacent cells and become long cells. The long cells become the fusiform initials. Radial divisions in some short cells occur occasionally. Some of these cells elongate and the rest remain in the axial files. Some short cells in the axial files are vertically separated from each other by the elongation of adjacent long cells. however, this occurs infrequently and the height of axial files is still several decades of cells. Short cells in axial files eventually become ray initials.     

Osservazioni sugli stadi iniziali della morfogenesi in coltura di alcune specie del genere Peyssonnelia Decaisne

Abstract

Researches on the morphogenesis of the genus Peyssonnelia Decaisne. — This paper reports the first result on morphogenetic researches in cultures of 3 species of the genus Peyssonnelia Decne. The development of Peyssonnelia rubra (Grev.) J. Ag. is of «Dumontia type »(CHEMIN, 1937) that one of Peyssonnelia squamaria (Gmelin) Decne. and of Peyssonnelia inamoena Pilger of «Naccaria type». According to our cultures results the morphogenesis of genus Peyssonnelia is of two type. Sample of P. squamaria and P. inamoena are collected in the gulf of Trieste (Nord Adriatic Sea) those of P. cfr. rubra in the Morlaix Bay (English Channel). Taxonomic value of the results are discussed.     

Effetto dell'Irraggiamento X sulla Biosintesi degli Amminoacidi in Piante di Orzo

Abstract

The effects of irradiation on aminoacids biosynthesis in barley. — The effect of radiations on the biosynthesis of aminoacids in barley has been studied. Seeds have been irradiated with X-tays of 7.5 and seedlings with 7.5, 15 and 30 Kr. After 6–7 days of growth the control and irradiated seedlings, and the seedlings from control and irradiated seeds, have been supplied with 10–100 μC of C¹⁴O₂ in a closed chamber for 44–42 hours. The material was extracted with hot ethanol (85%–80% and 40%). Total radioactivity and the radioactivity of the basic fraction, eluted with HCl from Dowex 50, X-8′ (200–400 mesh, H^?) have been measured. It was observed that radiations increase the radioactivity of the aminoacid fraction, both in leaves and roots. A correlation between the decrease of fresh weight and increase of aminoacids radioactivity was shown. A possible explanation might be visualized in terms of the inhibition of growth and protein synthesis by radiations.     

Ricerche sulla flsiologia della produzione di tossine in colture di Helminthospobium maydis Nishik. et Miy

Abstract

STUDIES ON THE PHYSIOLOGY OF TOXIN PRODUCTION BY HELMINTHO-SPORIUM MAYDIS NISHIK. ET MIY. CULTURES. — Helminthosporium maydis produces under artificial culture toxic metabolites, which are responsible of a reduction of wheat and corn rootlets growth, severe alterations in tomato shoots and young corn plants, and growth inhibition of some microrganisms.

Cultural conditions for growth and toxin production were studied. Different strains of the fungus vary in their ability of toxin production, the highest amounts being produced by each strain by somewhat different conditions. At least one toxic metabolite can be extracted by chloroform from the cultural filtrates, but probably more than one toxin is produced, and of them at least one is not extracted with organic solvents. Toxic substances can be extracted from the mycelia, but it is not yet possible identify the toxins obtained by the extraction of the mycelia with one or more of the toxic metabolites obtained by extraction of the cultural filtrates.     

Shoot morphology of Aucuba japonica incurred by anisophylly: ecological implications

Anisophylly, having leaves different in size and/or shape, was quantified in adult Aucuba japonica and simulations were carried out to evaluate the effects of anisophylly on the extent of self-shading at the single-shoot level as well as at the whole-canopy level. Clear anisophylly was observed in the individual after switching from the single-stemmed juvenile stage to the multi-stemmed adult stage. In such plants, leaf area in the canopy abruptly increased. The effective display of adult foliage involved a variety of morphological changes in addition to anisophylly, most prominently reduction in leaf size compared to juveniles. The simulation results indicate that diversity of leaf size and shape is an effective means of minimizing self-shading as well as allowing the efficient exploitation of a larger canopy volume in adult plants. Anisophylly also increased the biomass use efficiency of individual plants at maturity. Taken together, having diverse leaf forms is superior to having a single leaf form for maximizing area acquisition and for efficiently filling the acquired area. We therefore conclude that the anisophylly expressed in A. japonica is adaptive.     

Azione della Cinetina sulla Degradazione della Clorofilla in Foglie di Orzo Irradiate

Abstract

The effects of kinetin on chlorophyll breakdown in irradiated barley leaves. — Kinetin is shown to inhibit the breakdown of chlorophyll in isolated barley leaves. Moreover the kinetin is shown to inhibit, even if with lower effect, the chlorophyll breakdown in irradiated barley leaves. This possible correlation of these observations, with kinetin promoted protein synthesis is suggested.