Osservazioni Sull'embriologia di Nerine Rosea e di Amaryllis Belladonna (Amaryllidaceae)

Summary

The embryosac development in Nerine rosea Herb. has been found to occur according to the Normal type and indications of an identical development were found for Nerine curvifolia Herb., contrary to the observations of Schlimbach (1924), who reported a Lilium type for this species. Embryosacs of the Normal type also occur in Amaryllis Belladonna, to which a tetrasporic development had been erroneously ascribed by Schlimbach (1924). In Nerine rosea Herb. the formation of the microspores is of the «successive» type; the aploid cromosome number is n=12, in accordance with the describtions of Heitz.     

Metabolismo di Quiete e Metabolismo di Crescita

Summary

The changes in carbohydrate and phosphorus metabolism of tomato ovaries stimulated to growth by pollination or auxin treatment found in previous studies prompted an investigation of the enzymatic systems concerned. In this research, the effects of pollination and of auxin treatment on phosphorylase and on phosphatase activity were studied. Phosphatase splitting inorganic P from adenosine triphosphate was characterized as different from that acting on glycero- and hexose-phosphate by the difference in inhibition by beryllium and fluoride.

Two phases of growth occurring during the earlier stages of fruit development were clearly defined by the behavior of the enzymes considered. During the first (induction) phase both phosphomonoesterase and ATP-ase activity markedly dropped. This was followed by a marked rise in activity during the later stages of growth.

Phosphorylase activity, unlike that of the phosphatases, showed no relationship to the two phases of growth, and increased steadily during the period of observation. This agreed with the rate of starch synthesis observed in the growing auxin treated or pollinated tomato fruits.

Changes in the activity of these enzymes in the not pollinated, not auxin treated ovaries during the period of observation were, on a comparative basis, very small.     

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.     

Ricerche Comparate Sulla Morfologia e Sulla Fisiologia di Larix e di Picea

Abstract

Comparative researches on morphology and physiology of PICEA and LARIX. The chlorophyll content of seeds and seedlings during germinations in darkness. — Very different are the chlorophyll contents of the seeds and the seedlings of Picea excelsa and Larix decidua grown in darkness.

In Picea chlorophyll is abundantly synthetized in cotyledons in the passage from seed to seedling stages. In Larix however this synthesis is very poor. These differences are more evident after the outgrowth of cotyledons from the primary endosperm and its exhaustion.

If seedlings of both species are exposed to 3.000 lux of light intensity for 24 hours, after development in darkness, one can observe much stronger chlorophyll synthesis in Larix cotyledons than icea.

These figures quanti atively express the different light-dipendence of chlorophyll synthesis in these two plants and offer a more adherent interpretation of the different ecological behaviours that are caracteristic of these two plants.     

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.     

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.     

Flora Delle Argille e Dei Tufi di Civita di Bagnoregio (Alto Lazio)

Abstract

Flora of the clays and the tuffs of Civita di Bagnoregio (Upper Latium). — This work is the result of floristic research developed from 1968 to 1970 on tuffs and mainly on the clays of Civita di Bagnorcgio. After having summarily described the geo-ecological conditions, the author lists in all 489 entities. The biological spectrum of clays shows a high presence of Therophyta and a low percentage of Phanerophyta; on the contrary on the tuffs are present more Phanerophyta and less Therophyta; on the whole the flora is marked from the Emicryptophyta. Phytogeographical analysis indicates a prevalence of mediterranean elements. The author delineates moreover the most important floristic aspects, refering the frequentest entities and point out the intense anthropization wich has prevented the preservation of the woody formations, today completely away from clayey area.     

Fenomeni di variazione e di dissociazione nei miceti lievitiformi

Al Dr. C. Cavallero, per il presente lavoro, è stato conferito il premio Dr. Carlo Biroli, bandito dalla R. Università di Pavia per 1'anno 1937.     

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.     

Frammenti di Quereeto a Roverella e di Macchia Mediterranea a Vivara (Isole Flegree)

Abstract

Fragments of oak-crop with QUERCUS PUBESCENS willd. and of mediterranean maquis in the isle of vivara (Flegrean isles). — In these note the types of arboreous and shrubby vegetation pointed out in the islet of Vivara are passed in rapid review. Particular references to the types of vegetation arranged in the Quercion ilicis are given.

A short account is reserved to the presence of Quercus pubescens Willd. and to the importance of these species concerning the construction of the fragments of oak-crop and of mediterranean high maquis that are present to the edges of tableland and on the sides of the smallest Flegrean isles.

It is a question of unusual aspects of vegetation for a microinsular environment. Therefore they are worthy of study before they are destroyed or still more altered.     

Note floristiche e fenologiche nel territorio di Arneo (Fra Taranto e Gallipoli)

Summary

The author describes the vegetation and phenology of a Quercus Ilex wood in the Comprensorio dell'Arneo, betwen Taranto and Gallipoli along the eastern shore of the Ionian Sea (Golfo di Taranto). The wood consists partly of a degraded bushy vegetation.

The wood was visited eleven times during the year and each time species found flowering were noted (Table at pp 296–301): the greatest number of them, many being therothytes, was found on April 21rst (fig. 2) with about a month's delay in comparison with Palestine (Gindel). In May there is a considerable i decrease in number of species flowering. In summer and winter, because of drought and low temperature very few species, mostly geophytes, were found flowering, and only slightly but markedly more in Autum.     

La Posidonia oceanica: problemi di ecologia,di funzionamento e di biologia

Abstract

The functional roles of seagrasses in the economy of coastal waters are to be fully realised and more clearly delineated. The biology, ecology and energetics of seagrasses meadows of the Mediterranean Sea, and in particular of Posidonia oceanica inclusing the stabilization of coastal sediments, this role as a base for major detrital food chains, nutrient resources contributory to general productivity of the open sea and the support of dense epiphytic communities, are discussed.