Ricerche Sull'Azione Inibente di Alcune Antiauxine Sull'Attività di Deidedrogenasi Delle Frazioni Solubile E Mitocondriale di Estratti di Tessuti di Piante Superiori

Summary

Inhibiting effect of antiauxins on some dehydrogenare enzyme systems in the soluble and in the particulate fractions of extracts from plant tissues.

The effect of several antiauxins (trans-cinnamic acid, diphenylacetic acid, 2–4 dichloroanisole, b-phenylpropionic acid, maleic hydrazide) on dehydrogenasic systems in enzymic preparations from higher plant tissues (cauliflower, pea, artichocke) has been investigated. Dehydrogenase activity has been determined, in the soluble (glucose-6-phosphate) as well as in the particulate (malic TPN linked, malic DPN linked, succinic dehydrogenases) fraction of the protoplasma, by the tetrazolium (used «in vacuum») and the Thunberg methods. Mitochondrial preparations have been obtained through repeated precipitations at 20.000 × g., in the cold, in 0,5 M sucrose.

All of the antiauxins tested, at concentrations ranging between 60 and 400 p. p. m., clearly inhibited dehydrogenase activity, both in the soluble as in the mitochondrial systems. Inhibition appeared non competitive, and indipendent from coenzyme concentration; it was more evident at lower pH values, and it increased with pretreatment of the enzyme with the antiauxins, in the absence of substrate.

These results are interpreted as an evidence for the capacity of antiauxins to act directly on fundamental metabolic systems, even in absence of auxin.

The lack of specificity and the characteristics of the inhibiting action of antiauxins on dehydrogenase systems suggest that they could act through the inactivation of some chemical group of general diffusion and importance among the enzymes of the class here investigated; very probably, of -SH groups.     

Variazioni di attività della clorogenico ossidasi e di altri enzimi interessati all'ossidoriduzione del TPN durante l'attivazione di fettine di tubero di patata

Abstract

CHANGES IN THE ACTIVITY OF CHLOROGENIC ACID OXIDASE AND OTHER ENZYMES INVOLVED IN OXIDATION AND REDUCTION OF TPN IN AGEING POTATO TUBER SLICES. — The activation of respiration, and in particular of the pentose phosphate pathway, during incubation of potato tuber slices could depend on the increase of activity of oxidative enzymes mediating electron transfer from Gl. 6-P to oxygen.

The present report deals with the activity changes, in the first period of incubation, of the following enzymes: Gl. 6-P-dehydrogenase, TPNH-glutathione reductase, gluta-thione-dehydroascorbate reductase, chlorogenic acid oxidase and a TPNH diaphorase utilizing tetrazolium salts as electron acceptors.

The activity of all of these enzymes, with the exception of TPNH diaphorase, was found to bs, at all stages of incubation, in large excess respect that required to account for the estimated contribution of the pentose phosphate pathway to respiration.

Gl. 6-P dehydrogenase, glutathione reductase and chlorogenic oxidase activities markedly incresed during incubation; but their increase appeared to be clearly delayed (of some hours) respect that of oxygen uptake. This seems to indicate that the increase in activity of these anzymes is rather a consequence than a cause of the respiratory activation.

TPNH diaphorase showed a very low activity in the fresh slices, and it increased quite significantly already in the very first period (5 hours) of incubation. This behaviour suggests the possibility that this enzyme could limit TPNH oxidation, and thus the pentose phosphate pathway activity, and that its activation could be correlated with that of oxidative metabolism in the ageing slices. Further investigation of this hypothesis requires the identification of the natural electron acceptor of this enzyme.     

Impiego delle sezioni di coleoptile di alcune varietà italiane di frumento nel dosaggio biologico di sostanze promotrici ed inibitrici della crescita

Abstract

Growth response of coleoptile sections from four Italian cultivars of wheat to some growth regulators.—The following Italian wheat varieties were used to obtain the coleoptile sections used throughout the experiments: Funo, S. Pastore, Abbondanza, Generoso.

The growth substances tested were Indolacetic acid (IAA), Abscisic acid (ABA), Kinetin and Gibberellic acid.

The colcoptile response of each variety was tested with three different concentrations for each growth regulator in combination with two sucrose concentrations and three different pH levels.

The experiments indicated that the coleoptiles from the variety « Funo » react linearly to incresing IAA and ABA concentration resulting the best one to be used in this bioassay.     

Effetto di Inibitori Della Sintesi Proteica Sull'aumento di Attività Enzimatiche e sul Risveglio del Metabolismo Nell'Endosperma di Semi di Ricino in Germinazione

Abstract

Effects of inhibitors of protein synthesis on the development of metabolic activity in the endosperm during the germination of castor bean seeds. — The effect of chloramphenicol, streptomycin and actinomycin-C on the increase of the activities of glyceroaldehyde-phosphate dehydrogenase, aldolase, glucose-6-phosphate dehydrogenase, fructose 1–6 diphosphate-1-phosphatase, phosphomonoesterase, in the endosperm of germinating castor bean seeds was investigated.

In all cases, the protein synthesis inhibitors depressed the activation of the enzymes tested: in particular, actinomycin (50 μg/ml) completely suppressed the increase of the activities.

The development of the rate of oxygen uptake and the conversion of fats to sugars was strongly affected by the inhibitors.

These data suggest that the increase of the activities of several enzymes in the germinating endosperm is dependent on enzyme synthesis rather than on the conversion from the inactive to the active form of the enzymes.     

Alghe Bentoniche di Profondità Raccolte Alla Punta S. Pancrazio Nell'Isola di Ischia (Golfo di Napoli)

Abstract

Observations on deep seaweeds (15–50 m) at Punta San Pancrazio, Island of Ischia (Bay of Naples). — Algological research in little known and still well preserved zones of the Bay of Naples have been done to improve our knowledge of underwater flora of the Bay itself and of the southern part of the Tyrrhenian sea. SCUBA diving technique allowed us to detect, namely in the deepest investigated areas, a number of species previously unknown for the Bay of Naples. This research deals only with species found during the summertime, living at depths greater than 15 m.     

Sulle capacità di sviluppo della placca midollare in condizioni di espianto

Zusammenfassung Durch Anwendung der Explantationsmethode vonMangold wird der Rumpfschwanzteil der Medullarplatte in vitro explantiert, um die Evolutionsfähigkeiten der isolierten Medullaranlage und die Entwicklungskorrelationen zwischen dem Chorda-Mesodermkomplex und der Morphohistogenese des Rückenmarks zu studieren.Es wird vor allem festgestellt, daß der Neuralstrang, der sich aus der explantierten Neuralplatte bildet, auch ohne Mitwirkung der Chorda oder irgendeines Stützorgans verlängerungsfähig ist.Von großer Bedeutung für die Morphohistogenese des Neuralstranges scheint die Chorda zu sein, und gewissermaßen auch das Mesoderm.Fehlt das Mesoderm, so schmelzen die Ganglien zu einer einzigen Masse zusammen, ventral zum Neuralstrang; die Struktur des Neuralstranges erleidet aber dadurch keine Veränderung.Fehlt die Chorda dagegen, so treten sehr wichtige Veränderungen im Neuralstrang ein, d. h. übermäßige große der Neuralröhre oder mehrfache Röhrenbildung, Zerstörung der Zellen- und Fasernanordnung, Neuroblastenabsonderung aus dem Rumpfteil des Neuralstranges.Wenn aber, auch bei fehlender Chorda, der Neuralstrang von Mesodermmassen begleitet wird, ist seine Struktur viel regelmäßiger.Es scheint also, daß das Mesoderm, außer die Wirkung auf die Zerteilung der Ganglienanlagen, auch gewissermaßen die ausgebliebene Wirkung der Chorda ersetzen kann.     

Sul grado di accestimento delle piante di grano colpite dalla “Carie„

Abstract

We numerically analysed 154 relevés of Potentillo chrysocraspedae–Festucetum airoidis in order to review the compositional variability of these grasslands, the main eco-floristic gradients and the representativeness of the lectotype. Apart from 30 small-sized clusters composed of singular or transitional relevés (outliers), three distinctive groups of 77, 19 and 12 communities were finally retained and denominated as typical (TP), closed (CL) and open (OP) facies, as they were significantly different in terms of total species cover. The three facies are well separated but do not form distinctive clusters in the non-metric multidimensional scaling (NMDS) ordination space. Juncus trifidus and Agrostis rupestris are the best differential species of OP and TP, respectively, whereas the best discriminator of CL is the higher cover of F. airoides. There are no significant differences between the three facies regarding altitude. The floristic structure of CL indicates poorer but moister soils compared with the other facies. CL may represent either a post-disturbance, recovery phase following sheep overgrazing and intensive trampling, or a late seral stage. OP gathers communities that are little disturbed and mainly occur on ridges and upper, sunny slopes. Although well distinguished floristically, TP is weakly defined in terms of homotoneity and complexity of the core species assemblage. The most representative relevé of TP is poorer in character species than the relevé lectotype (5 versus 12), the latter being classified as an outlier in terms of normal specific assemblage. Such patterns may reflect the spatio-temporal heterogeneity in alpine grasslands due to uncontrolled, intensive grazing and stochastic natural disturbances.     

Germinazione «In Vitro» di Carpospore di Petroglossum Nicaeense (Duby) Schotter

Abstract

In vitro development of carpospores of Petroglossum nicaeense (Duby) Schotter. This paper describes the germination of carpospores of P. nicaeense (Phyllophoraceae) and the development on glass of new tetrasporophytes to the size of 3–4 mm. Different patterns of development are observed: 1) formation of one or two rizoidal filaments which give rise to an adhesive disc; 2) formation of a morula, of limited growth, and of rizoidal filaments which then originate adhesive discs; 3) formation of a morula which originates a single frond, and formation of filaments that do not form adhesive discs. Eventually, the discs give rise to one or more outgrowths that develop into erect fronds. These fronds reach a 4 mm length 3 months after germination.     

Fissazione di C14O2 in Colture di Tessuti Vegetali « in Vitro »

Abstract

C¹⁴O₂ fixation in plant tissues « in vitro ». — In the present work it has been examinated the autotrophic and heterotrophic CO₂ fixation of explants of « Helianthus tuberosus » « in vitro » and the photosyntetic efficiency of leaves produced from buds of « in vitro » explants of « Cichorium intybus » compared with that of mature leaves from normal plants of the same species. From our results it is evident that « in vitro » explants of « Helianthus tuberosus », grown, in the light, are able to autotrophically incorporate C¹⁴O₂; the distribution of the radioactivity into the various fractions shows a large influence of the light on the neutral fraction containing sugars (50% of the total radioactivity). In the chlorophyllous explants the dark CO₂ fixation is obviously of heterotrophic type: 97% of the total radioactivity is incorporated in amine acids (43%) and the organic acids (53%); on the other hand in the dark grown explants the radioactivity is differently distributed between amino acids (59%) and organic acids (39%). Mature leaves from normal plants and leaves produced from buds of « in vitro » explants of « Cichorium intybus » incorporate the same quantity of C¹⁴O₂ when expressed per mg of chlorophyll; the different distribution of the radioactivity in the neutral and acid fractions could be explained in terms of a different utilization pathway of the photosynthates in the two tissues.     

Valutazione dei dati aerosporologici ottenuti in due diverse stazioni di rilevamento di una stessa città

Riassunto Nel presente lavoro vengono riportati gli studi quantitativi e qualitativi delle spore micetiche presenti in due diverse zone della città di Cagliari. I rilevamenti sono stati effettuati nei mesi di Febbraio, Marzo ed Aprile del 1987 utilizzando capsule di Petri contenenti “Potato dextrose agar” più antibiotico. Sono state osservate differenze significative nella frequenza delle spore delle due zone considerate. Nel corso dell'intera ricerca abbiamo isolato 6702 colonie filamentose appartenenti a 15 generi diversi; 6 generi sono stati repertati costantemente. Sulla base della quantità e varietà delle specie micetiche identificate, gli Autori ritengono che le spore aerodiffuse possono costituire un fattore di rischio non trascurabile.      

Sulla Presenza di Ificellarioli e di Conidi in Mieobionti Lichenici Coltivati in « Vitro ». Riassunto

Abstract

On the presence of « hyphycellariola » (swollen celles) and conidia in three lichenized fungi cultivated « in vitro ». — The Authors refer to the presence of « cellariola » (and « hyphycellariola ») found in pure cultures « in vitro » of the mycobiont of Xanthoria parietina and describe the morphology of conidia in the fungus isolated from Sarcogyne similis and Acarospora fuscata.

As far as the « cellariola » and « hyphycellariola » are concerned, it is the first note relative to the mycobionts of Lichens.

The Authors report the data of the utilized medium and the morphological observations.

This previous studies will be intensified by further research.     

Attività enzimatiche in vivo ed in vitro negli abbozzi di organi di Gallus domesticus durante l'ontogenesi

Riassunto E' stato seguito lo sviluppo ovulare del fegato nel Gallus dom., mediante tecniche istochimiche atte a rivelare attività fosfatasica acida, esterasiche non specifiche e colinesterasiche. L'indagine si è poi estesa ad abbozzi o frammenti di fegato coltivati in vitro.

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Zusammenfassung Die Leber von Gallus dom, wurde mit enzymhistochemischen Methoden zum Nachweis von Carboxylsäureesterasen und saurer Phosphatase während der ganzen Entwicklung und in der ersten Zeit nach dem Schlüpfen untersucht. Im Leberparenchym treten die Phosphatase und die mit alpha-Naphthylacetat, Naphthol-AS-Acetat oder 5-Brom-Indoxylacetat nachweisbaren Esterasen sehr früh in Erscheinung, während mit der Methode nach Koelle und Gerebtzoff keine Reaktion auf Cholinesterasen zu erhalten ist. Im Mesenchym und im Epithel der Gallenwege sind die Phosphatase bzw. die unspezifischen Esterasen in keinem der untersuchten Stadien aktiv, und da die Volumenzunahme und die Differenzierung des Lebergewebes keinen Änderungen in der Lokalisation der Enzymaktivitäten entspricht, ist anzunehmen, daß diese nicht überwiegend an die Entwicklung der Anlage gebunden sind.Auffällig ist die ungleichförmige Verteilung der unspezifischen Esterasen in der Leberanlage. Im blutgefäßnahen Teil des Cytoplasmas der Hepatocyten und besonders in den Leberzellen um die zentrolobulären Venen sind die Esterasen am aktivsten, was wohl dafür spricht, daß diese Enzyme an den Leberstoffwechsel gebunden sind. Die saure Phosphatase ist gleichförmig im Parenchym verteilt, und man muß demnach annehmen, daß die beiden Enzymgruppen — saure Phosphatase bzw. unspezifische Esterasen — nicht in der gleichen Weise in die histogenetischen Prozesse eingreifen.Bei der Züchtung eines Stückes der Leberanlage in vitro erhält man ganz charakteristische histotopochemische Bilder. Im Zentrum des Explantats entspricht die Reaktion auf Phosphatase oder Esterase derjenigen, die man in vivo im gleichen Entwicklungsstadium erhält, was wohl auch damit zusammenhängt, daß dieser Teil des Explantats keinen stärkeren Strukturumwandlungen unterliegt. In den Fällen, in denen es auch nur zu leichten Degenerationserscheinungen kommt, nimmt die Aktivität der unspezifischen Esterasen allerdings eindeutig ab. An der Peripherie des Explantats, wo man einige Schichten unterschiedlicher Struktur beobachten kann, ändert sich das normale Bild der Enzymreaktionen. Die das Explantat umhüllende Mesenchymmembran ist enzymlos, während die unter dieser in vitro gebildeten Hülle beerenartig angeordneten Hepatocyten eine Reaktion auf Phosphatase und Esterase geben, die der in vivo auftretenden Anfärbung entspricht. Die zwischen der äußersten Parenchymschicht und dem zentralen Kern des Explantats liegende Zellschicht besitzt keine deutliche Struktur und ist von verschiedenartigen Zellen, auch solchen in Degeneration, durchsetzt. In dieser Schicht erhält man die stärkste Reaktion auf Phosphatase und unspezifische Esterasen, was ein Anzeichen dafür ist, daß es sich hier um eine sehr vitale Zone handelt.

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Le ricerche sono state eseguite sotto gli auspici del C. N. R. italiano.     

Nuovi reperti di intersessualità nelle Cucurbitacee

Abstract

The aim of this paper is to investigate differences in plant species composition between managed and unmanaged forests, and to assess if these difference give rise to a higher plant diversity in the unmanaged forest. Furthermore our aim is to relate forest structure to differences in plant species composition, identifying the structural attributes more strongly related to the unmanaged forest vegetation. We compared an old-growth forest and a managed highforest in the Abruzzo Lazio and Molise National Park (Central Italy). Plant species composition and diversity, deadwood components and live structure have been analyzed. We used permutational multivariate analysis of variance to test the response of species composition to management factor; furthermore, we compared species richness and beta diversity. Redundancy analysis has been used to relate plant species abundances to structural variables; the importance of dead and living wood components has been compared through variation partitioning. Plant species composition proved to be significantly different in the two sites, and the old-growth stand showed a higher plant diversity. From a structural point of view, we found differences especially in the amount and quality of deadwood, and in the diameter class distribution. These variables are also the most important in determining the old-growth stand plant species composition according to redundancy analysis. Variation partitioning confirmed the greater importance of the deadwood variables. Our results suggest that including deadwood surveys in traditional forest inventories could help in finding forests with both structural and floristic old-growth properties to be considered in conservation programmes. The imitation of natural dynamics, through the creation of gaps avoiding deadwood removal, could be an effective strategy for restoring old-growth conditions, also in terms of plant diversity.     

Ricerche sull'infrastruttura del coleottile di avena: I. — Il fascio vascolare in corso di differenziazione

Abstract

STUDIES ON THE INFRASTRUCTURE OF THE OAT COLEOPTILE. I. - THE DEVELOPING XYLEM CELLS. — The writers are engaged with a research program dealing with the morphological changes effected in the cell infrastructure by growth substances. The problem, obviously, requires an intimate knowledge of cell infrastructure of all different tissues of the test used, the oat coleoptile in this case. With this first note, cell infrastructures of the xylem region of the bundle (parenchyma and tracheids) are described, limitedly to the portion 1 mm behind the coleoptile tip, where cell divisions are completely suppressed while cell elongation and differentiation are set on.     

Affinità floristica dei tipi di vegetazione bentonica della Cala di Mitigliano (Massa Lubrense,Napoli)

Abstract

Floristic affinity of bentonic vegetational types of Cala di Mitigliano (Massa Lubrense Napoli). — We have studied the bentonic plants community in the Cala di Mitigliano. It appears that some species compositions repeat themselves with a certain regularity. This fact lets us recognize and consequently classify them. In Cala di Mitigliano we took an interest and considered only such species compositions. We calculated, in them and between them, the coefficient of affinity by SÖRENSEN (1948). The cluster analysis by average linkage and the use of an index of «individualisation» (Feoli, ined.) based on floristic comparison showed that the species compositions, although we chose such ones to describe the vegetation, equally change gradually from place to place.     

Autecologia di Ulva rigida: 1. Influenza dell'intensità luminosa e della temperatura sulla produzione di ossigeno

Abstract

Autecology of Ulva rigida C. Ag.: 1. Influence of light intensity and temperature on oxygen production. The photosynthetic activity of Ulva rigida, growing in Bari's harbour (Adriatic Sea), has been assessed in the laboratory by measuring oxygen evolution as a function of white light intensities. Tests were performed at four temperatures. The data indicate the remarkable amount of O₂ released in the environment.     

Frequenza di cellule con « DNA puffs » nel sospensore di Phaseolus coccineus in momenti diversi dello sviluppo embrionale

Abstract

Morphological aspects of Phaseolus coccineus suspensor cells at different periods of embryo development. — Embryo suspensor cells of Phaseolus coccineus have been analysed at different periods of seed and embryo development in field-grown plants and the frequency of cells involved in « DNA puffs » formation has been determined. The collected data show that: a) the relation between seed development and embryo development is not constant at different times in the season (from July to November); b) the frequency of cells showing « DNA puffs » is influenced by the above ratio. This fact seems to indicate that embryos of comparable developmental stages (as estimated by cotyledon length) show different metabolic patterns in relation to seed development and enviromental factors.     

Le Infezioni Con “Stubborn” Ottenute per Trauma E Il Grado di Recettività dei Tipi di Grano

Abstract

Dioecy ensures cross pollination but pollen must travel from male to female plants, sometimes covering long distances. The present study concerns the reproductive strategy of two Italian dioecious plants: Mercurialis annua L. and Bryonia dioica L. The former is anemophilous and the latter is entomophilous; the latter has nectar and pollen as rewards. The distribution of pollen grains on the stigma is very different in the two species, reflecting the different types of pollination. In both species there is a number-dependent mechanism of pollen germination on the stigma. This mechanism could enhance male gametophytic competition.     

Relitti Mediterranei all'imboccatura di Cavità Ipogee Carsiche

Abstract

Mediterranean relicts at the mouth of karstic caves. — Far away from the mediterranean maquis stretched along the coast of Trieste, we can still find some groups of rank evergreen-oaks with several other mediterranean species.

The survival of these thermophile species is probably due to warm ascensional drafts, coming just in winter from the underneath caves.     

Le modalità d'accrescimento degli assoni studiate a contrasto di fase in espianti di tessuto nervoso „in vitro“

Riassunto Le espansioni terminali degli assoni, che crescono in vitro, possono presentare aspetti diversi. La forma più comune é quella, da lungo tempo nota, di ingrossamenti dell'apice del neurite, i quali emettono esili filamenti ameboidi, transitori. Ma, nelle fibre che crescono nell'interfacie tra un mezzo solido e un mezzo liquido, spesso l'espansione risulta di tenui membraneile ialine in continuo movimento, le quali possono avere varia estensione.Le espansioni membraniformi possono venire in breve tempo retratte e sostituite da fini filamenti ameboidi indipendenti e viceversa; tra queste varie strutture esistono forme intermedie.Non risulta però confermata l'opinione di A. HUGHES che i filamenti transitori siano pieghe di una struttura continua.I vari aspetti, che le espansioni possono assumere, sono l'espressione della grande plasticità della sostanza nervosa. L'accrescimento delle fibre nervose a contatto di una superficie solida é verosimilmente condizione indispensabile, ma non sufficiente per la formazione delle espansioni membraniformi; é probabile che la sostanza del neurite si espanda in veli estremamente tenui, soltanto quando é soggetta a fenomeni di imbibizione, associati a diminuzione della tensione superficiale.Membrane ialine possono essere emesse anche all'apice delle collaterali e, in casi più rari, costituirsi transitoriamente persino lungo il decorso del neurite, a spese di tratti più o meno estesi di questo, che si espandono in superficie.Le fibre nervose in accrescimento presentano manifesti fenomeni di pinocitosi. Essi avvengono sia in corrispondenza dell'espansione terminale, sia nelle collaterali, sia infine lungo il decorso del neurite, in zone in cui esso emette esilissimi filamenti transitori, apparentemente privi di espansione terminale.Si ritiene ehe, con l'introduzione di goccioline di liquido, il neurite assuma dall'ambiente materiali disciolti, i quali, insieme alle sostanze che vengono elaborate dal pirenoforo e che fluiscono nel neurite stesso, verranno utilizzati per l'accrescimento della fibra nervosa.Vien prospettata l'ipotesi che il significato dei fini ramuscoli collaterali, transitori, che il neurite in accrescimento emette di continuo lungo tutta la sua lunghezza, sia essenzialmente trofico.Ricerche eseguite con un contributo del Consiglio Nazionale delle Ricerche.