Esperienze Di Estivazione Su Urginea Maritima Bak.

Abstract

Aestivation experiments on URGINEA MARITIMA Bak. — Bulbs of Urginea maritima Bak. have been subjected to artificial aestivation in different months (March, April, May, June) in order to find out the most appropriate period for forced blossoming. The bulbs, once taken out of the soil, have been kept for a whole month at 28° C, with atmospheric humidity not strictly controlled but never falling below 48%.

Aestivation in March and April, when the plant is in its full vegetative activity, caused suppression of the sexual phase. Aestivation in May, when the vegetative activity of the plant is approaching its end, caused total flowering anticipated of about 20 days. Aestivation in June, when the plant is at the beginning of its resting period, had no effect on flowering.

These results seem to show that the leaves create in the course of their activity the necessary conditions for flowering and that this critical stage is reached, in the plants under examination, between April and May.

In the plants treated in May that is after they had reached the critical stage, the flowering was not suppressed; on the contrary it occurred earlier than in the plants left in their natural habitat. The advancement of the time of flowering corresponded more or less to the anticipation of the artificial as compared with the naturally occurring aestivation.     

Sul Presumibile Antagonismo Tra Sviluppo Vegetativo e Fiorale e Su Un Nuovo Caso di Formazione di Gemme e di Foglie Su Spine di Aurantiaceae

Riassunto

L'A. facendo delle osservazioni comparative tra le caratteristiche di sviluppo vegetativo e fiorale rilevate tanto sui rametti ordinari che nei casi anomali di formazione di gemme su spine di Aurantiaceae mette in rilievo il presumibile antagonismo tra sviluppo vegetativo e fiorale che si verifica in genere tra le due importanti attività fisiologiche della pianta.

Nello stesso tempo dà notizia di nuovi casi di formazione di gemme e di foglie su spine di Citrus limonum L. che, confrontati con quelli descritti in precedenti lavori dell'A. riguardanti lo sviluppo di fiori su spine di Aurantiaceae, confermano che gli abbozzi fogliari contigui alle gemme si evolvono regolarmente quando la gemma sia polarizzata nello sviluppo vegetativo o sia allo stato latente, mentre restano in genere allo stato rudimentale quando la gemma viene a polarizzarsi verso lo sviluppo fiorale. Ciò si verifica in generale negli abbozzi fogliari che si sviluppano sulle rachidi fiorali ed eccezionalmente in quelli che sono in rapporto con la gemma che dà origine ad una rachide fiorale.     

Osservazioni Anatomiche e Fenologiche Su Diotis Maritima Desf

Summary

The Author studies the anatomy and phenology of Diotis maritima Desf. which grows along the sea shores of Messina (Sicily) as a sand fixing psammophyte.     

Studio Comparativo della Struttura e del Ciclo Biologico di Due Diatomee di Acqua Dolce: Navicula Minima Grun. E Navicula Seminulum Grun.: III. Esame Dei Caratteri di Navicula Minima Grun. E di Navicula Seminulum Grun

Abstract

Comparative study of the structure and of the biological cycle of two fresh water diatoms: « Navicula minima » Grun. and « Navicula seminulum » Grun. III. Examination of the characteristics of « N. minima » Grun. and « N. seminulum » Grun. — After studing separately the Navicula minima Grun. and the Navicula seminulum Grun. the various characteristics of the two have been compared and contrasted for purpose of classification. The form and dimentions of the frustules, the density and the structure of the streaks, the structure of the walls, the life circle, aspects of their growths, and some anomalies, most especially, as regards the streaks were examined. It was found the among such numerous characteristics, only one, that is, the presence of the streaks formed by double rows of pores in N. seminulum rather than of a simple file as in N. minima makes one thinks that, in spite of strong similarities existing between these two Naviculae, they are to be regarded as belonging to e different systematic classes. However, their actual positions in taxonomy May-June be defined by further research into the structures and the variabilities of the frustules of other species of Naviculae similar to those examined.     

Fenomeni di Inattivazione e di Riattivazione Enzimatica in Endospermi di semi di Ricino

Abstract

Inactivation and riactivation of enzymes in endosperms of castor bean seeds. — On the basis of previous results, the possibility has been investigated of the reversible interconversion of active and inactive form of enzymes in castor bean seeds, during their development.

The results described here indicate that:

1. the activity of some glycolytic enzymes increases greatly (81% and 400% increase of, respectively, Gl-6-P-dehydrogenase and aldolase) upon incubation of dry seeds for few hours at 4 °C.

2. The decrease of enzyme activity upon dehydration of seeds and the increase during the subsequent imbibition can be shown reproducibly.

3. This same observation is made for oxygen uptake.

These results are interpreted to indicate the reversible inactivation of enzymes caused by dehydration of seeds.     

Azione esercitata da alcuni inibitori respiratori sulla crescita e sull'inverdimento di plantule di Picea abies e di Larix decidua

Abstract

Action of some respiratory inhibitors on growth and greening of seedlings of Picea and Larix.—The effects of sodium azide, arseniate, jodoacetate, fluoride and 2,4-dinitrophenol on growth and greening of dark germinated seedlings of Picea abies and Larix decidua were studied.

All the inhibitors showed a negative influence on growth (determined as fresh weight) of Picea seedlings and even more remarkably on Larix seedlings.

Greening was significantly inferior to that of control plants only for groups of Picea seedlings treated with sodium azide, at all the concentrations used, and for groups treated with fluoride and arseniate at the highest concentrations.

All the groups of Larix seedlings, instead, treated with inhibitors, with the exception of the ones treated with sodium fluoride at the lowest concentrations, presented a chlorophyll content inferior to that of control groups.

From the above results the different influence of inhibitors on Picea and on Larix seedlings might be due to the different metabolic pathways through which the pigment synthesis in the two species under study takes place.     

Azione esercitata dal cianuro sulla crescita e sull'inverdimento di plantule di Picea abies (L.) Karsten e di Larix decidua Miller

Abstract

Action of cyanide on growth and greening of seedlings of Picea abies and Larix decidua.—The effects of cyanide on growth and greening of dark germinated seedlings of Picea abies and Larix decidua are studied. While growth of Picea seedlings is scarcely inhibited, the effect of the inhibitor on Larix seedlings is very drastic. Greening of Picea seedlings is never inhibited while, at stronger concentrations, cyanide weakly inhibits greening of Larix seedlings. When seedlings are treated with cyanide and salicylhydrossamic acid, an inhibitor of mithocondrial respiration cyanide non-sensible, growth is inhibited more strongly than when cyanide only is used and greening too is inhibited. Cyanide is shown to be able to reach megagametophyte and embryo and to be incorporated steadily.     

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.     

Contenuto Dell'AIA Libero in Plantule di Vicia Sativa Cresciute in Diverse Condizioni di Ambiente. I. Plantule Cresciute Al Buio e Alla Luce

Abstract

Free beta-indoleacetic acid content in shoots of « Vicia sativa » seedlings grown in different environmental conditions. I. Seedlings grown in the dark and in the light. — Free IAA has been determined in shoots of Vicia sativa seedlings grown in the dark and in the light. The alcohol extract of the vegetable material has been submitted to several processes of purification (changes of PH and washing-out in ether, and successively column as well as thin layer chromatography). Lastly the IAA eluted with alcohol from the chromatographic slides is spectrometrically determined (λ = 280 mμ). The data show that the free IAA is contained to a greater extent in the seedlings grown in the dark in comparison to those grown in the light; this difference permaining in the samples of the same age as well as in those of the same height. The obtained data have been submitted to statistical analysis and both assays have shown to be highly significative.     

Correlazioni tra organi di senso e centri nervosi in via di sviluppo

Zusammenfassung In FÄllen, wo beiLoligo-Embryonen infolge der Einwirkung von Lithiumchlorid die Augenentwicklung asymmetrisch gehemmt ist, entspricht der gehemmten Entwicklung der Augen immer eine solche des zugehörigen Augenganglions. In seltenen FÄllen kann man auch beobachten, da\ zu einem gehemmten Ganglion ein normales Auge gehört, aber niemals das umgekehrte. Diese Korrelationen sind nicht durch Lagebeziehungen bestimmt. Bringt man diese Tatsachen mit denen zusammen, die über diese VerhÄltnisse bei Vertebraten bekannt sind, so kommt man zu dem Schlusse, da\ höchstwahrscheinlich das Cephalopodenauge die Entwicklung des zugehörigen Augenganglions leitet.