Sul Naturale Imbianchimento dei Tepali di Giacinto in Precedenza Verdi E sulla Irreversibilità dei Cloroplasti

Abstract

On the natural bleaching of hyacynth (HYACINTHUS ORIENTALIS) tepals, green in earlier stages, and on the unreversibility of chloroplasts. — The theory of Schimper (1885), according which the types of plastids are interchangeable, and which some authors (Frey-Wyssling, Ruch and Berger 1955; Frey-Wyssling, 1961) rejected on the ground of the new views on the submicroscopic cell morphology, has not yet received, from the electron microscope, neither evidence, nor criticism. One of the most discussed points, and for which we still need further observations, is represented by the interchangeability of the chromatophores (chloroplasts and chromoplasts) into leucoplasts. The few observations reported, indeed, dealt with genetical situations (Robbelen, 1959) or abnormal and pathological states (Gerola et al., 1960, 1962); and their conclusions might therefore receive some criticism which — from the view of the problem here studied — invalidates their real value. In this paper, the author follows, with the electron microscope, the chloroplast involution in the tepals of Hyacynthus, which are green before the anthesis, but bleach when blossom. Chloroplast structures are described, and their progressive changes reported. The writer can conclude that, at least in the material used, the chloroplasts cannot change into leucoplasts, but gradually involve, always keeping, until the latest stages, their characters of green plastids. Some observations are also reported, on the different structure of the stroma lamellae and of the grana lamellae, on the ground of their different behaviour during plastids involution.     

Determinazione dei pollini aerodiffusi nella città di Varese nell'anno 1986

Riassunto Nel presente lavoro sono state riportate le concentrazioni polliniche registrate nell' atmosfera di Varese nel 1986. Le principali famiglie di pollini presenti sono state quelle delle Graminacee, Urticacee (Parietaria officinalis) e Betulacee (in particolare Betula alba), seguite da Corilacee, Fagacee, Salicacee e Cupressacee. Scarsa importanza hanno dimostrato, per le basse concentrazioni raggiunte, le Chenipodiacee, le Plantaginacee ed in particolare le Composite. In generale i risultati ottenuti non si sono di molto discostati da quelli riscontrati nel 1985.

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Summary This research reports the results of the airborne pollen samplings carried out with a volumetric VPPS 2000 sampler elaborated daily in the area of Varese during year 1986, from March to September. These results were related to some meteorological data (temperature, humidity and rain). The principal pollen's families found are those of Gramineae, Urticaceae (parietaria off.), Betulaceae, Corylaceae, Fagaceae, Salicaceae and Cupressaceae. Chenopodiaceae, Plantaginaceae and Compositae have demonstrated little importance because they reach low concentrations. Generally the results obtained in the year 1986 and in 1985 are similar.

     

Il problema della Eredità considerato dal punto di vista chimico-fisico

Abstract

A study on the type and distribution of trichomes, morphological traits of the calyx and content of antioxidant compounds was conducted on Teucrium arduini L. populations in Croatia and in Bosnia and Herzegovina. Non-glandular trichomes, peltate trichomes and small capitate trichomes with four secretory head cells were observed on leaves, stems and calyx, whereas long capitate trichomes with a unicellular head cell were observed exclusively on the calyx. Average calyx length was 5.23–6.51 mm, calyx tube length 2.92–3.68 mm, lower lip length 1.25–2.42 mm and upper lip length 1.89–2.99 mm. The concentration of antioxidant compounds in all populations was the highest in leaves: total polyphenols (TP): 8.43–13.55%; tannins (T): 1.79–7.33%; flavonoids (TF): 0.28–0.40%; phenolic acids (TPA): 2.90–5.07%. Inflorescences generally contained the smallest amount of TP (5.89–11.42%), T (0.87–6.50%) and TPA (1.66–2.27%), while the smallest content of TF was obtained for the majority of stem samples (0.06–0.12%). The researched populations did not differ with regard to the type and overall distribution of the trichomes, though the Bosnian populations have a shorter calyx tube and longer upper lip. Some variability was observed in the TP and T content between sampling sites, while quite high variability was noted in the TF and TPA content.     

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.     

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.     

Sulla variabilità cromatica dei fiori nelle specie di Crocus L. delle Alpi sudorientali italiane

Abstract

Chromatic variability of tepals in species of Crocus L. of South-eastern Alps.—The anthocyanidins causing the color of tepals of some species of Crocus L. in the Italian South-eastern Alps were determined and characterized. The genus Crocus of this region is represented by four entities: C. napolitanus Mord. & Loisel., C. albiflorus Kit. ex Schult., C. reticulatus Stev. ex Adam. and C. weldenii Hoppe ex Baker.

The distribution of anthocyanidins in the four entities confirms the existence of a systematic distance among the species belonging to Reticulati and the species belonging to Anulati. Two anthocyanidins, i.e. delphynidin and petunidin, which are always present in other entities, have not been found in C. weldenii; this species is characterized by the only presence of malvidine.

The anthocyanidins assume therefore in this case a chemotaxonomic meaning.     

Ricerche Sul Meristema Apicale della Radice. VII L'attività di Alcuni Enzimi Della Glicolisi,del Ciclo di Krebs e di Quello dei Pentoso Fosfati

Abstract

Studies on root apical meristem. VII. Activities of some enzymes of glycolysis, of the Krebs cycle and of the pentose phosphate cycle. — The enzymes assayed are: aldolase, glyceraldheyde-3-phosphate: NAD oxidoreductase, triosephosphate isomerase, fumarate hydratase, aconitate hydratase, glucose-6-phosphate: NADP oxidoreductase, 6-phosphogluconate: NADP oxidoreductase. The determinations were made on pea roots (Pisum sativum cv. Alaska) which were obtained by germinating seeds on moist vermiculite, in the dark, at 25° C, either for 2 or 7 days. In both cases samples were collected from the meristematic zone (0-2 mm from the apex) and from the extending zone (2-4 mm from the apex). All the enzymes determined are present both in the meristematic and in the extending zone of the root. If referred to a fresh weight basis, their activities are always greater in the meristem; if referred to a dry weight or to a protein basis, the values in the meristematic zone are nearly equal to, or higher than those in the extending zone. With respect to the development of the cell in the root from the meristematic to the vacuolated state, the present results indicate that the change in volume is accompanied by increases is the enzymes tested.     

L'Azione dell'Ossigeno Liquido Sulla Germinabilità dei Semi Duri di Ginestrino (Lotus Corniculatus L.) e di Ladino (Trifolium Repens L.)

Abstract

Comparative researches on morphology and physiology of PICEA and LARIX. Fresh weight and chlorophyll content in seedlings kept at various light intensities. — The fresh weight and the chlorophyll content of lots of seedlings from Larix decidua and Picea excelsa grown on sand for 12 days in climatic cell at 25 [ddot]C with 86% relative humidity and a light intensity of 90, 250, 500, 1.000, 2.000 and 4.000 lux were determined.

The fresh weight of Picea seedlings is not significantly affected by all light intensities except for 4.000 lux, where it is 20% higher. Even in dim light (90 lux) the fresh weight of Picea seedlings is only 7% inferior to that of the lot kept at 2.000 lux.

The results obtained in Larix are remarkably different; its fresh weight is more influenced by the light intensity: at 4.000 lux, e. g., the fresh weight is considerably higher (more than 20%) than the arithmetical mean of all the lots, while at 90 lux it appears greatly inferior (30%) to the lot kept at 2.000 lux.

No correlation exhists between fresh weight and chlorophyll content variations.

In Larix only the difference between seedlings kept at 250 lux and 90 lux is very strong. In the latter the chlorophyll content for g. f. w. is 40% inferior to the average of all the lots. At the maxime intensities the chlorophyll content of Larix seedlings appears to be particularly increased, while that of Picea seedlings is slightly inferior to that observed at 2.000 lux.

These figures are in agreement with the special ecology of the two plants and particularly with the light need of Larix, as it is clearly demonstrated by the fresh weight and chlorophyll content per g. f. w. and by the different ratio in chlorophyll contents of the lots of seedlings kept at 2.000 and 4.000 lux.     

Le Stipule e la Fillotassi di “Tropaeolum Majus” L

Riassunto

Le stipule della plantula di Tropacolum majus L. sono emergenze occasionali, che nella pianta adulta sono sostituite nella loro funzione dalla lamina dei nomofilli. La sua fillotassi sparsifolia è derivata dalla oppositifolia per crescenza asimmetrica spiralata della periferia dell'asse.     

Indagini Sui Pollini Fossili di Alcune Località Della Calabria (Sila Piccola e Serre) Con Osservazioni Sulla Vegetazione Attuale

Abstract

Researches into the fossil pollens in some localities of Calabria (Sila Piccola and Serre), with observations about the present vegetation. — This study concerns two groups of localities both in the province of Catanzaro (Calabria): the former in Sila Piccola and the latter in Serre. The authors refer the principal local characteristics of the two regions: geological nature, short pedological notes and climate. Some tables are shown (tab. 1, 2 and 3) with thermic and pluviometric data of some localities nearest to the studied areas. BAGNOULS and GAUSSEN'S xerothermic diagram (fig. 2) is made for these localities. Great evidence is given to the fresh and oceanic character of the climate of the tablelands of the Serre, in relation to the more continental one of the Sila Piccola with its rigorous winters and dry, hot summers. This seems to justify the difference of distribution of the arboreous vegetation existing between the two regions. In fact, in the Sila Piccola, the vegetation belt between 1000 and 1500 mts., is occupied by woods almost entirely of Pinus laricio, while in the Serre, the same vegetation belt is occupied by Abies alba and Fagus silvatica. These two latter species can be found in Sila Piccola above 1500 mts. The authors shortly describe the pollen analysis of several peat bogs, and the criteria used for the floristic surveys and stational tests. In the Sila Piccola five areas are examined (fig. 3), three in the Serre (fig. 7). From the borings made in the Sila it is possible to obtain the pollen diagram for three localities (Spinarva, Tirivolo, Macchia dell'Orso, figg. 4, 5 and 6). On the contrary, in no areas of the Serre any fossil pollen has been found. In fig. 8 the forest cycles of the Sila Piccola are synchronized with those of other localities in the North and Central Apennines. The examination of the pollen diagrams allows some considerations: the pine-woods of the Sila (presumably Pinus laricio) have rather ancient origin in the post-glacial period. In the past they had a larger diffusion also in areas where now grow woods of Fagus silvatica with Abies alba (Spinarva and Macchia dell'Orso) and in some periods with a climate different from the present one. The pollen diagram of Spinarva shows that the antagonism we found in the Sila, as in the whole of the Apennines, between Abies alba and Fagus silvatica, is characterized by three distinct phases. The discovery of the pollen of Picea (figs. 4 and 6), is very interesting because it proves the presence of the red spruce in the calabrian mountains during the post-glacial period. The authors describe the localities where the borings were made together with the tests of the structure of the arboreous vegetation surrounding such localities, and the floristic surveys. As to the woods of Pinus laricio, we notice the lack of a characteristic florula. In fact, this is very heterogeneous. Nevertheless the prevailing species have a helio-xerophilous character, according well with the character of Pinus laricio itself. The beech-woods of the Sila Piccola generally have a high density and as regard the cultivation are of contemporary type. In their interior we notice few mesophilous species with rare species with more helio-xerophilous character. The presence of many young plants of Abies alba is very important. These vegetate with difficulty in the interior of the dense beech-wood. Where the arboreous canopy diminuishes, and in the glades, the silver fir develops and grows vigorously (fig. 13). Thus we observe, in the Sila Piccola, a dynamic competition, still existing, between Abies and Fagus, just as in the past. The authors suggest to favour the expansion of silver fir in the beech-wood, on the occasion of cultural interventions in the forest, in order to reach a suitable balanced mixture between these two species. It is interesting to note the presence of Ranunculus brutius and Phyteuma trichocalycinum (figs. 9 and 10) in the beech-woods of the Sila Piccola. The analysis of the vegetation and that of the climatic elements and the relevés made in the fir-wood of Serra San Bruno, show that the higher parts of the Serre are particulary suitable for a mesophilous vegetation, dominated by Fagus silvatica and Abies alba. As regards Pinus laricio, we may say that, in the region of the Serre, it does not find very favourable conditions for developing. The authors, finally, suggest some cultural directions to be followed in the reafforestations in the region of the Serre.