Ricerche sulla Vegetazione della Valsesia

Summary

The present work, forming a part of the research on the Valsesian vegetation, is an investigation of the botanical aspects of one of the tributary valleys of the Mastallone torrent, the Sabbiola valley.

The valley has steep flanks cut into compacted crystalline rock; this morphology is very different from other valleys cut through esasily erodible rock, and with gentle slopes, and has marked influence on the vegetation.

At the base of the valley a forest of Alnus incana and Fraxinus Ornus and, ascending, a stand of chestnut trees not very extensive was noted.

Betula pendula was noted as high as 1200 meters (above sea level). Beech trees, more or less heliophilus or acidophilus are extended lo higher elevations, up to 1500 m., and started at about 850–900 m. The hypsophylous conifers were missing and the “cacuminale” vegetation was neither very extensive or typical, because even the highest elevations of this valley are relatively low for this type of vegetation.

The study of the vegetation of this valley upon completion will be incorparated and inte preted together with the results of other research on the Valsesian region.     

Ricerche sulla distribuzione altimetrica della vegetazione in italia

This contribution introduces the ongoing research on herbaceous bamboos started by the University of Florence (FT herbarium), the Universidad de Panama (PMA herbarium) and the Smithsonian Tropical Research Institute in 2011. The main goal of this project consists in collecting field data, in order to provide updated material to be used in a phylogenetic analysis to improve the knowledge of the complex tribe Olyreae.     

Ricerche sulla differenziazione e sull'accrescimento della cartilagine in condizioni meccaniche sperimentalmente modificate

Riassunto Allo scopo di studiare le ripercussioni di profondi mutamenti delle condizioni meccaniche ambientali sulla differenziazione e l'accrescimento della cartilagine della sclera, si determinÒ in una serie di embrioni di polio al 4⁰ giorno di incubazione un collasso dell'abbozzo dell'occhio destro. In conseguenza del collasso, il bulbo oculare, i cui singoli costituenti si differenziano in modo tipico, si accresce in misura considerevolmente ridotta in confronto all'occhio dell'altro lato, il cui sviluppo non fu turbato. Già due giorni dopo il collasso del calice retinico, il mesenchima che lo circonda e che è destinato a differenziarsi in gran parte nella cartilagine della sclera, costituisce una massa più spessa che di norma ma assai meno estesa in superficie.A partire dalla fine del 6⁰ giorno d'incubazione, tale mesenchima si differenzia in cartilagine; in quest'ultima le cellule sono più addensate dal lato leso che da quello indenne. La densità dei condrociti per unità di volume di cartilagine non muta in modo significativo durante tutto lo sviluppo embrionale. La percentuale di condrociti in mitosi nella sclera dell'occhio ridotto, decresce un po' più rapidamente che nella sclera normale a partire dal momento nel quale inizia la differenziazione dell'abbozzo della sclera in cartilagine; invece, la sintesi di solfato di condroitina nella sostanza intercellulare, saggiata con lo studio dell'incorporazione di radiosolfo per un periodo di 24 ore, non presenta differenze apprezzabili nella sclera dell'occhio ridotto in confronto a quello che si accresce normalmente.La quantità assoluta di cartilagine che costituisce la sclera dell'occhio ridotto è considerevolmente minore di quella dell'occhio normale. Risulta dalle presenti ricerche che la differenza nell'accrescimento fra le sclere dei due occhi dipende non da variazioni dell'accrescimento interno ma da una cospicua riduzione dell'accrescimento apposizionale della sclera dell'occhio ridotto, sopratutto in corrispondenza del margine laterale della sclera al limite con la cornea (limbo sclerocorneale). In altre parole, nell'occhio ridotto vengono a mancare le condizioni meccaniche indispensabili per la progressiva estensione in superficie della sclera, la quale è dovuta ad un intenso accrescimento apposizionale al margine sclero-corneale.

---

Zusammenfassung Ziel vorliegender Untersuchungen war es, die Folgen von starken Veränderungen der mechanischen Bedingungen des Milieus auf die Differenzierung und auf das Wachstum des Skleralknorpels festzustellen. Bei einer Serie von Hühnerembryonen wurde am 4. Bebrütungstage ein Kollaps der rechten Augenanlage veranla\t. Während die Differenzierung der einzelnen Bestandteile durch den Kollaps des Augapfels nicht beeinträchtigt wurde, war sein Wachstum erheblich reduziert, in Vergleich mit dem des gegenseitigen Augapfels, dessen Wachstum ungestört war. Schon 2 Tage nach dem Kollaps des Augenbechers kommt es zu starken Veränderungen in der Form des umgebenden Mesenchyms, welches sich grö\tenteils zum Skleralknorpel differenzieren soll; die Mesenchymmasse wird plumper; ihre Flächenausdehnung wird erheblich reduziert. Vom Ende des 6. Bebrütungstages ab differenziert sich das Skleramesenchym zu Knorpel, in dem die Zellen im Vergleich zur unversehrten Seite verdichtet erscheinen. Die Dichtigkeit der Knorpelzellen je Volumeneinheit von Knorpel bleibt während der ganzen Entwicklung des operierten Embryos unverändert. Der Prozentsatz der Mitosen der Knorpelzellen in der Sklera des reduzierten Auges sinkt in Vergleich mit der normalen Sklera von dem Moment etwas rascher ab, in dem die Differenzierung der Skleraanlage in Knorpel stattfindet. Dagegen wurden, wenn man die Einverleibung der Menge von Radioschwefel in die Grundsubstanz während einer Periode von 24 Std untersucht, keine nennenswerten Unterschiede im Skleralknorpel des operierten Auges in Vergleich zu dem des gegenseitigen Auges konstatiert; dadurch wird bewiesen, da\ die Synthese von Chondroitinschwefelsäure in der Knorpelgrundsubstanz durch die Reduktion der Sklera nicht beeinträchtigt wird.Es ergibt sich aus vorliegenden Untersuchungen, da\ die absolute Menge des Knorpels der Sklera in Vergleich mit dem normalen Auge erheblich reduziert wird; doch hängt die Reduktion nicht von einer Verminderung im inneren Wachstum ab, sondern von der Reduktion des appositionellen Wachstums in der Sklera des reduzierten Auges, besonders am lateralen Rande der Sklera, an der Grenze mit der Hornhaut (Limbus Corneae). Kurz, es fehlen im reduzierten Auge die mechanischen Bedingungen für die progressive Ausdehnung in der Fläche der Sklera, welche durch ein intensives appositionelles Wachstum am Limbus Corneae hervorgebracht wird.

     

Ricerche sulla fisiologia dell'acido ascorbico

Summary

The aim of this first contribution to the ecological meaning of the ascorbic acid, is specifically to search the relations between thermoperiodical conditions and the ascorbic acid content in green plants.

The effect of variations of the night-temperature (by unvaried daily conditions) on the ascorbic acid content, has been assayed throghout a series of esperiences.

On the whole, it has been observed, as a first result, an inverse relation between the degree of night-temperature and the ascorbic acid content of the leaves (night-t° betweeen 12° and 28° C; test-plants: Nicotiana Tabacum L., v. Java; Lycopersicum esculentum Mill. v. S. Marzano; Solanum tuberosum L., v. Majestic; Impatiens balsamina L.).

The possible practic finality of these investigations and some theoretic considerations, especially concerning the ecological point of view, are discussed.     

Ricerche sulla fisiologia dell'acido ascorbico

Summary

Structural viscosity of plasm in plants varies over a wide range under the influence of a number of different stimuli, as both internal and surrounding factors are bound to affect it. If viscosity is regarded as an index of the dispersion degree of plasmatic colloids, it will be easily gathered that, parallel with it, also the reactive surface of these is subject to both quantitative and qualitative variations. The result is that such stimuli as determine the aforesaid variations in the living plasm structure, ultimately should have a bearing on the intensity of all such functions as are controlled by plasm. Of all the stimuli bound to exert the effects referred to above, the Authors have devoted their special attention to auxins. Under their influence the plasm structure undergoes such modifications — which can be appraised with the plasmolysis method — that an increase in viscosity is noted, the latter phenomenon being followed — in the Authors' opinion — by an increase in the dispersion degree of the plasmatic colloids. Consequently, several functions are enhanced, the most evident of these being the cells' growth. On the other hand, in such cells where the membrane have reached such a degree of evolution as to be no longer extensible, the auxins cause the same phenomena as in the plasm, without this being, however, accompanied by a resumption of the growing process.

The Authors have expressed the opinion that plants may have a way to regulate the rate of such functions as are controlled by plasm not only by producing some substances wich, by causing a higher dispersion of the plasmatic colloids, act as stimulants, but also by producing some other substances having an opposite action; these substances, by exerting the contrary effect on the plasmatic colloids, would act as inhibiting agents. According to this assumption the auxin-type substances would be offest by some anti-auxinic substances, the actual extent of all functions, as well as the reaction to surrounding stimuli, would thus be controlled by a system of two classes of regulators having opposite effects, and by their relative amount. In the last few years several researchers have investigated the anti-auxin field; the Authors, however, specifically refer to the ascorbic acid (AA) as the mos widely diffused an the one having the most general significance.

In this paper the Authors propose to study antagonist relation between auxins and AA under the limited standpoint of the effect that the two substances exert on the plasm's structural viscosity. Their experimental results have shown that

a) the administration of AA, no matter which technique has been used, cuts the plasmolisys time (if concave in the controls, the latter become convex in the tissues treated), consequently decreasing the plasm viscosity. Such a reduction, which is noted in both the stem and roots, is, at least to a certain extent, proportional to the amount of AA actually to be found in the organs;

b) the very same result is obtained when a variation is introduced in the surrounding conditions which, by affecting the photosynthetic process, influence the amount of AA which is present in the organ. More particularly, it has been found that, after being kept for a certain number of hours in the dark, the vegetal organs — notably the leaves and green stems — contain far lower amounts of AA than those which could be found when the same organs were exposed to the light. Likewise, the plasm viscosity is far higher in the dark than in the light.

Etiolated plants, too, contain a far lesser amount of AA than the controls which have grown in the light, and their plasm is far more viscous than in the green controls. The experimental introduction of AA, anyway, lowers the plasmatic viscosity both in the etiolated specimens and in the controls.

The roots, wich are extremely poor in AA contents as compared with the green organs, also have a far more viscous plasm;

c) the antagonist relation between the action of the AA and the substances having an auxinic action is also indirectly evidenced by the AA being capable of cutting or even offsetting the action of the auxinic type substance. As a matter of fact, in such plants as have been experimentally enriched in their AA contents the plasm viscosity undergoes only a very slight variation subsequent to the administration of substances exerting an auxinic action.

It is, anyway, a well-know fact that roots, being extremely poor in AA as compared with the stem, are influenced to a far larger extent than the latter by the action of all growth-promoting substances; d) AA is not a specific antagonist of the auxins. As a matter of fact, it has been found that it opposes the action developed by indoleacetic and indolebutyric acids, as well as the action exerted by some other substances, such as xanthine, uric acid and colchicine whose auxin-like action on both plasm viscosity and cellular enlargement has already been detected.     

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.     

Ricerche Sull'ultrastruttura della Parete Cellulare

Abstract

A study about the cell wall of AVENA coleoptile epidermis cells. — A new type of lamellae structures embedded in the outer periclinal wall of oat coleoptile epidermis cells has been observed. These structures are present more frequently in the inner non-cutinized portion of the cell wall; their orientation, most often parallel to the cell surface, follows a regular pattern. They are formed by alternate layers of electrontransparent and electron-dense bands. The thickness of these lamellar bodies is about 200–300 Å; their length is rather difficult to determinate. They are bounded by a 30–40 Å thick membrane; the inner compartment is formed by a central highly manganophilic zone 50–70 Å thick where several thin lamellae can be seen and by two lateral zones about 40–50 Å in thickness.

Embedded in the cutinized portion of the wall some elliptical bodies have also been observed, surroundedd by a single membrane, 20 Å in thickness. The interior of these bodies shows thin lamellae enclosed in an electron-transparent stroma.

In experimental conditions unfavourable to growth, the frequency of these structures falls greatly. When the cell distension comes to end, their aspect undergoes deep changes. It is proposed in this paper that these new structures are involved in cell wall growth and development.     

Ricerche sulla capacità lentogena dell'iride degli Anfibi

Conclusioni Dal settore irideo superiore diTriton eDiscoglossus trapiantato autoplasticamente nell'orbita (dopo enucleazione del globo oculare) o sotto la cute, con o senza retina, non si forma mai una lente. Se invece l'innesto viene praticato nella cavità addominale allora, in una certa percentuale di casi, si ottiene una lente. CiÒ porta a pensare che nel determinismo del fenomeno una grande importanza debba essere attribuita allo spazio a disposizione del pezzo nella sede d'innesto. Molta importanza spetta anche alla presenza di retina ne l'innesto, giacchè i casi in cui si è avuta rigenerazione di lente appartengono tutti ad esperimenti di innesti di iride con retina.In questi esperimenti, in un certo numero di casi, si è anche avuta la formazione di lentoidi.Negli innesti nell'orbita e nell'addome quasi costante è la rigenerazione di retina dal materiale irideo innestato e niolto frequente la regolazione dell'innesto in forma di globetto oculo-simile.La rigenerazione della retina puÒ aver luogo o dalla pars iridea retinae o direttamente da qualsiasi punto dell'iride per diretta metaplasia delle cellule iridee in cellule retiniche.Negli innesti sotto cute invece il pezzo innestato va in genere incontro a disfacimento.Negli innesti nella cavità dell'orbita quasi costantemente si sono viste fibre nervose partirsi dalle masse retiniche e, attraverso alforo ottico, giungere fino al diencefalo. Negli innesti nella cavità addominale invece non si è mai vista tale neoformazione di fibre nervose.

---

Zusammenfassung Vom, in der Orbitahöhle (nach Entfernung des Auges) oder unter der Haut autoplastisch transplantierten oberen Irisrand mit oder ohne Retina vonTriton oderDiscoglossus aus, regeneriert nie eine Linse.Transplantiert man dagegen das Irisstück in die Bauchhöhle, so bildet sich in einigen Fällen eine Linse. Das bringt zur Annahme, da\ in der Linsenregeneration aus einem isolierten Irisstück der Raum, der dem Stück in der Transplantationsstelle zur Verfügung steht, von höchster Wichtigkeit ist.Von Bedeutung ist auch die Retinaanwesenheit im transplantierten Stück, weil in allen Fällen, in denen man eine Linse erhalten hat, auch die Retina mittransplantiert worden war. Bei diesen Experimenten hat man in einigen Fällen auch Lentoiden erhalten.In den meisten Fällen der in der Orbita- oder Bauchhöhle transplantierten Stückchen regeneriert die Retina vom Irismaterial aus und sehr oft bildet das Stück kleine augenähnliche Kugeln.Die Retinaregeneration kommt entweder aus der pars iridea retinae oder, ganz einfach, aus einer jeweiligen Irisstelle zustande durch Metaplasia der Iris- in Retinazellen.Die unter der Haut transplantierten Irisstückchen dagegen gehen fast immer zugrunde.Aus den in der Orbitahöhle transplantierten oder regenerierten Retinastückchen gehen fast immer Nervenfasern aus, die, durch das Foramen opticum das Zwischenhirn erreichen.In den Transplantationen in der Bauchhöhle bemerkt man nie eine solche Nervenfasernbildung.

     

Ricerche sulla Flora Infestante Delle Colture in Italia

Summary

The Author has watched statistically the weeds of the coltures with a triennial rotation in a ground of Alta Lunigiana (Massa-Carrara) where the climate is rather mild with a great quantity of rain for annum; therefore he made a comparison between the weeds studied by some other authors noticing remarkable differences especially regarding to Bari's weeds.

Finally the Author mode a phytogeographycal analysis classifing the principal weeds following Eig's methode.     

Ricerche Sulla Vegetazione della val Gesso

Abstract

An interesting discovery in the Maritim Alps flora. ARTEMISIA CAMPHORATA Vill. with galls of DIARTHRONOMYIA KIEFFERI Trotter. Its geographical distribution and phytogeographical analysis. — The Author signals the finding, in the Maritim Alps flora, of some stations of an interesting discovery: Artemisia camphorata Vill. with galls of Diarthronomyia (Rhopalomyia) Kiefferi Trotter, and explains the characteristics of this Cecidomyide, (gall-midge).

He exhibits the results obtained through inquiries (investigations) directed to define the geographical area of Diarthronomyia Kiefferi, in reference to that of its host plant, of which the zoocecidium is exclusive.

The author makes also a map of the area and analyses the phytogeographical characte ristics and the mediterranean physiognomy of the new found stations.     

Ricerche sulla flora infestante delle colture in Italia

Summary

Studies on the weeds of cultivated land in Italy. IV: Weeds of a small farm near Montecatini Terme.

In the first part of this researche, the author gives the chief climatic data of the Montecatini Terme zone together with pedological informations about the stations offered by a small farm on which biological and statistical investigations are conducted.

All weeds (241 species) found on the area of the small farm are listed. For each species is indicated Raunhiaer's biological form, its occurence in cultivated fields or in path lanes, graves and fences.

The most of them are Therophytes (55%) and Hemicriptophytes (30%). Scarcely represented are the Geophytes (8,33%), Chamaephytes (3,75%), Phanerophytes (2,92%). Therophytes increase very much (till 78%) if only are considered the species which occur in cultivated ground.

In the second part of the work is conducted a bio-statistical study on the weeds behaviour in eight fields. Once a month, on thiese fields, statistical relieves have been made after Raunkiaer's method. The results are condensed in graphics in which, besides the percent frequences of the various weeds, are also reported the various biological stages, the types of root-system and the influence of the tillages.

Follows an examination of the weeds which have been found in the various cultivations (wheat, patatoes, corn, legumes ecc). The most important weeds (36 species) are, then, biologically and phyto-geografically classified in accordance with Korsmo's and Eig's systems, respectively. Of these weeds 81% are «seed plants» and 19% are «wandering plant» 52,7% belong to «liason group», 36,1% are polychorous or adventicious, 11,2% belong to mediterranean Element. «Stationary plants» are missing, it depends upon the fact that there are only annual crops.

At last, for the most important weeds, details are given about germination, blossoming and dissemination time, their relations with crops, their occurrence in the low or in the high part of the farm.

For a resume, conclusions are as follow:

1^°) The slope of the ground influences weed distribution on the fields of the farm; many of them (specially the winter-spring species) prefer cool fields of the low part of the farm, so that the high one is infested by a relatively small number of weeds;

2^°) the greatest number of weeds is found in the fields in spring time;

3^°) annual plants are prevailing over perennial ones;

4^°) the most infested crop is weat, the least is potatoes;

5^°) Variations of winter precipitations and, sometimes, of the sowing time may influence gravity of infestation by weeds.     

Ricerche chimico-istologiche su la lignificazione della membrana

Riassunto

L'A. studia il comportamento della membrana di fronte ad alcune soluzioni coloranti a reazione attuale diversa. Stabilisce il potere di assunzione dei colori da parte della lignina, dello xilano, della cellulosa, del legno, con il semplice esame microscopico e con esami colorimetrici, e viene a stabilire alcune nuove norme per giudicare su la lignificazione della membrana. Egli stabilisce che quanto più acida è la soluziene colorante in cui si manifesta la colorzaione con il verde di metile, con il verde di malachite, con il bleu di metilene, con il violetto di genziana, tanto più alto è il grado di lignificazione della membrana.