Germinazione E Accrescimento Dell'Abete Bianco (Abies Alba Mill.) In Diverse Condizioni Termiche E Fotoperiodiche

Abstract

Germination and growth of ABIES ALBA mill. in different light and temperature conditions. — The results of a research on white fir from different localities are summarized as follows:

a) Germination of seeds from three italian localities (Tuscany, lat. 43°, 44'; Abruzzo, lat. 41°, 52'; Calabria, lat. 38°, 33') has been tested in several ecological conditions (temperature, light and chilling); it has been found that 22 °C, 8 hrs. of light and a 3 weeks prechilling at 5 °C, are stimulating conditions for all the seeds. The Cala-brian seeds seem the most reactive.

b) Growth in different photoperiodic conditions has been tested on seedlings from the Appennine, from France (lat. 49°, 10') and Poland (lat. 49°, 39'). Growth is evidently stimulated by long-day conditions in all the seeds experimented and growth acceleration touches its maximum in the Calabrian seedlings, provided they germinated at 12°C in the ligth.

It has been concluded that Calabrian Abies behaves as a Biotype, evidently distinguished from all the others, and an ecological explanation of this behaviour has been attemped.     

Studio Floristico e Fitogeografico Delle Piccole Isole della Sardegna Nord-Occidentale

Summary

The author has studied the flora of the little islands of Northe-West Sardinia. In a former note he has referred on Isola Piana, in this one he refers on: Isola Rossa, Isola dei Porri, and Isola Foradada.

After having done the census of the species, notifying particularly the dominant ones and after having put in evidence the principal plant communities he kept his attention on some endemic species two of which are probable endemisms new to the science: Olea europaea L. v. latifolia (mihi) and Smilax aspera L. v. inermis (mihi), coming to the conclusion:

1°) The study should confirm the hypothesis that in the little islands may be manteined species, or ancient in regression, or recent in variation the recessive characters of which would be substracted to overcome of the dominant charaters of a largest population;

2°) The florae of the four islands, for theier geographical position are the expression of the Mediterranean half-dry climate;

3°) They present their plant communities from which springs the autonomy of the different «Ecoidi» with theier different predominance established by the equilibrium attained in them.     

Indipendenza della differenziazione istologica e della morfogenesi del cristallino

Zusammenfassung Verfasser berichtet über die abnormale Entwicklung der Linse eines Hühnerembryos, bei dem im Stadium von 10 Urwirbeln Mittelhirn und Rautenhirnanlagen entfernt wurden. Infolge eines ausgedehnten Blutergusses wurde die Morphogenese des Augenbechers und des anliegenden lentogenen Ektoderms gestört. Die Einstülpung des präsumptiven lentogenen Ektoderms fiel aus und an Stelle der Linse bildete sich eine scheibenförmige Verdickung des präsumptiven lentogenen Ektoderms. In der Mitte bestand diese aus sehr hohen prismatischen Zellen, die sich unter allmählicher Abnahme der Zellhöhe in die niedrigen Zellen des Hautektoderms fortsetzten. Verfasser erblickt darin ein Beispiel von Aufhebung des Zusammenhanges zwischen Morphogenese der Linse und Differenzierung der sie bildenden Zellen. Infolge der besonderen örtlichen mechanischen Bedingungen verblieben die Zellelemente, die zur Umwandlung in Linsenzellen bestimmt waren, an der Oberfläche im Zusammenhang mit dem Deckepithel, die gleichen Bedingungen schufen einen allmählichen Formübergang zwischen den Zellen, die den Linsenfasern ähnliche Merkmale zeigten, und jenen, welche das vordere Linsenepithel bilden sollten.     

Lineamenti agronomici e selvicolturali della Lucania

Abstract

Agro-sylvicultural aspects of Lucania. In the Basilicata Region one can find many types of natural habitats from the mediterranean « macchia » to the rocky peaks of Monte Pollino. Natural environmental factors greatly condition land utilization and sub-spontaneous plant formations such as forests, opens scrubs, and grazing lands, occupy 49% of the productive land (53% in the Province of Potenza alone): this is a high figure as compared to the one for the whole of southern Italy (37.5%). Forested land is 18% of the total and also this value is higher than the corresponding one for the whole of southern Italy (14.4%). Cereals are the main crops: the economy of Basilicata is therefore mainly based on pastoral-cereals growing activities.

The regional flora is very interesting including as it does several relict and endemic species. The most precious jewel for nature lovers is the over 6000 feet high, richly forested, massif of Pollino where one can find some of the few Italian stands of Pinus leucodermis, and, among the animals, the extremely rare Gypaëtns barbatus, besides what is probably the only Italian autoctonous roe-deer population.

The conservation of so many naturalistic riches does not necessarily clash with the regional economic development.     

Contributo allo Studio Floristico e Fitogeografico degli alti Pascoli della Montagna della Duchessa

Summary

After having summarily described the ecological conditions of the «Montagna della Duchessa» the author lists the plants collected in this area by him and earlier by Martelli and Anzalone. Notes on the geographical distribution of some species in the most important mountains of Central Italy and critical remarks on the taxonomy of some plants are added to the list. Some taxa must be regarded as having been found for the first time in the Abruzzi.

On the basis of the biological spectrum and of the percentage of the geographical elements, the author takes into account the ecological and phytogeographical features of this flora and points out its affinity with the flora of the lands with an arctic climate.

The author describes the commonest plant-communities, by means of statistical investigations, lists of plants with frequency of each taxa, and field notes. Finally he takes into consideration some peculiar features of the flora of this area.     

Flora Delle Isole Palmaria e Tino (Golfo Della Spezia)

Abstract

Flora of Palmaria and Tino islands. — Palmaria and Tino are two small islands at the entrance of the Gulf of La Spezia. They are formed of grey fossiliferous limestones of the Rhaetian period and of more recent — but still of the Rhaetian period — dolomitic limestones. Their climate is definitely more mediterranean than that of the La Spezia coasts laying near by; the winters are milder and the annual precipitations much lower (at the Palmaria 525 mm, at La Spezia 1375 mm. The flora is composed of 399 entities and has a biological spectrum in which the Hemicryptophytes predominate (35,33%), however also the Therophytes (29,57%) and the Geophytes (15,03%) are frequent. The test of the floristic composition shows that the eumediterranean elements are predominant (24,56%) but also the submediterranean (12,53%) and the central southern European (13,53%) are frequent; besides, the subatlantic (6,01%) and the Eurasian ones are also to be found (9,27%). From the test of the floristic components of the three floras of Palmaria and Tino, Capo Caccia in north western Sardinia and of the Marettimo island in western Sicily, it has been found that there is a bigger quantity of eumediterranean elements than in the islands near La Spezia (24,56%) at Capo Caccia (42,14%) and at Marettimo (47,60%), and on the contrary a decrease of the central southern European (13,53%, 9,50%, 6,40%). The fact that the island of Sardinia was separated from the continent since very early times is proved by the presence at Capo Caccia of a lower number of euro-centralasiatic plants (6,76%, 3,30%, 6,60% respectively), of sub-Atlantic ones (6,01%, 1,65%, 3,80%), and of Eurasian ones (9,27%, 7,85%, 8,20%) and on the contrary by a higher number of Sardinian-Corsican endemisms at Capo Caccia (8,67%), definitely higher than the ones in Sicily at Marettimo (3,40%) and the Tuscan-Ligurian endemisms at Palmaria and Tino (only 0,75%) islands which are a few dozen meters near the coast, from which they were separated in recent periods. Among the plants of phytogeographycal interest I would like to mention Centaurea cineraria which is present at the Palmaria and Tino with the var. veneris; may be once spread on most of the Mediterranean coasts. Most of the Mediterranean plants growing on the Palmaria and Tino have a distribution area which includes a great part of the Mediterranean. Just a few of them (Cephalaria leucantha, Argyrolobium zanonii, Phagnalon sordidum, Staehelina dubia, Pinus pinaster, Antirrhinum latifolium) are western submediterranean, distributed mostly in Europe; in comparison, at Marettimo there are western eumediterranean plants growing in northern Africa with some remains in the Spanish peninsula. At Marettimo eastern eumediterranean plants also grow, while at Palmaria and Tino are to be found only some plants that, from the north-eastern coasts of the Mediterranean sea, reach the interior of the Balkan peninsula (Genista januensis) or the Pontic region. (Coronilla cretica, Dorycnium pentaphyllum var. berbaceum).     

Istogenesi e differenziazione dei neuroni e degli elementi gliali della corteccia cerebrale

Zusammenfassung Vorliegende Untersuchungen bezwecken, die Histogenese der Groß-hirnrinde beim Schafe von den frühesten Stadien der Differenzierung der Neuronen und der Gliazellen ab durch die Golgische Chromsilbermethode zu erforschen. Ferner wurden die Änderungen in der Form der Neuronen und der Gliazellen in späteren Stadien der Entwicklung bis zur Geburt verfolgt. Die Beobachtung von His, daß bipolare Neuroblasten von der Keimschicht gegen die Oberfläche der Rinde wandern, wurde bestätigt. Die bipolaren Neuroblasten sammeln sich in der kompakten sog. 'Bil-Dungszone (Koelliker), wo sie sich schon in frühen Stadien der Entwicklung mit der Chromsilbermethode färben. Der obere plumpere Fortsatz der bipolaren Neuroblasten wird zu einem Dendrit (dem Spitzenfortsatz der reiferen Pyramidenzelle), der untere gegen die Keimschicht gerichtete Fortsatz wird zum Neuriten. Die sog. Bildungszone wird durch Einwanderung von Neuroblasten von der Tiefe allmählich dicker; bald differenzieren sich die oberflächlichsten Neuroblasten weiter und wandern in entgegengesetzter Richtung, d. h. gegen die tieferen Schichten, wo sie in verschiedener Höhe stehenbleiben und das charakteristische Gepräge der Pyramidenzellen annehmen. Gleichzeitig fährt die Wanderung von Ganglienzellen von der Tiefe gegen die Oberfläche der Rinde fort. Dieser Vorgang vollzieht sich während der ganzen fetalen Entwicklung und sogar nach der Geburt, wenn die mittlere Schicht eine beträchtliche Dicke erworben hat. Dadurch wird die Zahl der Neuronen bis in späten Perioden des Wachstums allmählich größer. Die Differenzierung der Ganglienzellen, welche in späten Stadien wandern, wenn sogar die weiße Substanz eine beträchtliche Dicke erreicht hat, fährt fort. Die Zellen gewinnen die Merkmale der reifen Zellen (lange Dendriten, Tigroidschollen im Cytoplasma) lange bevor sie ihre definitive Lage erreicht haben. Diese Zellen werden zu den polymorphen Zellen der fertigen Hirnrinde.Die Stützsubstanz der embryonalen Hirnwand besteht ausschließlich aus Fortsätzen der Ependymzellen. Diese bilden sich nur bei dem 250 mm langen Schaffetus zurück. Die Gliazellen erscheinen lange bevor die Fortsätze der Ependymzellen verschwinden, in verschiedenen Höhen der Hirnwand, in der Bildungszone und in der intermediären Schicht. Die Gliazellen sind in der fetalen Rinde mit zahlreichen, feinen Fortsätzen versehen, die ihnen ein besonderes, von dem der reifen Gliazellen verschiedenes Gepräge verleihen. Beim Fortschreiten der Entwicklung unterliegen sie einer tiefen Umwandlung dergestalt, daß neue, ganz verschieden aussehende Fortsätze an Stelle der fetalen erscheinen. Vor der Geburt ähneln sie stark den protoplasmatischen Astrocyten. Die beobachteten Umwandlungen sollen als Ausdruck der ameboiden Tätigkeit der Gliazelle gedeutet werden.Meinen Beobachtungen nach stammt nur ein Teil der Gliazellen von umgewandelten Ependymzellen ab, welche sich aus ihrer ursprünglich tiefen Lage nach der Oberfläche verschoben haben. Andere Gliazellen gehen aus Spongioblasten hervor, d. h. aus Zellen, welche ihren Ursprung direkt aus der Keimschicht nehmen, als scheinbar undifferenzierte Zellen durch die Hirnwand wandern und sich später zu Gliazellen differenzieren [Schaper (1897), Lenhossék (1891)].

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Alle presenti ricerohe ha contribuito il C.N.R.