Nuovi reperti di intersessualità nelle Cucurbitacee

Abstract

The aim of this paper is to investigate differences in plant species composition between managed and unmanaged forests, and to assess if these difference give rise to a higher plant diversity in the unmanaged forest. Furthermore our aim is to relate forest structure to differences in plant species composition, identifying the structural attributes more strongly related to the unmanaged forest vegetation. We compared an old-growth forest and a managed highforest in the Abruzzo Lazio and Molise National Park (Central Italy). Plant species composition and diversity, deadwood components and live structure have been analyzed. We used permutational multivariate analysis of variance to test the response of species composition to management factor; furthermore, we compared species richness and beta diversity. Redundancy analysis has been used to relate plant species abundances to structural variables; the importance of dead and living wood components has been compared through variation partitioning. Plant species composition proved to be significantly different in the two sites, and the old-growth stand showed a higher plant diversity. From a structural point of view, we found differences especially in the amount and quality of deadwood, and in the diameter class distribution. These variables are also the most important in determining the old-growth stand plant species composition according to redundancy analysis. Variation partitioning confirmed the greater importance of the deadwood variables. Our results suggest that including deadwood surveys in traditional forest inventories could help in finding forests with both structural and floristic old-growth properties to be considered in conservation programmes. The imitation of natural dynamics, through the creation of gaps avoiding deadwood removal, could be an effective strategy for restoring old-growth conditions, also in terms of plant diversity.     

Impiego delle sezioni di coleoptile di alcune varietà italiane di frumento nel dosaggio biologico di sostanze promotrici ed inibitrici della crescita

Abstract

Growth response of coleoptile sections from four Italian cultivars of wheat to some growth regulators.—The following Italian wheat varieties were used to obtain the coleoptile sections used throughout the experiments: Funo, S. Pastore, Abbondanza, Generoso.

The growth substances tested were Indolacetic acid (IAA), Abscisic acid (ABA), Kinetin and Gibberellic acid.

The colcoptile response of each variety was tested with three different concentrations for each growth regulator in combination with two sucrose concentrations and three different pH levels.

The experiments indicated that the coleoptiles from the variety « Funo » react linearly to incresing IAA and ABA concentration resulting the best one to be used in this bioassay.     

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.     

Segnalazione e descrizione di lieviti nelle „acque di vegetazione” delle olive

Questo lavoro vede la luce con un ritardo di circa otto anni, per le difficultà inerenti lo stato di guerra. A causa delle stesse ragioni, le collezioni dei lieviti isolati e studiati è andata perduta; ma data la frequenza e la relativa loro costanza nel substrato d'isolamento, non dovrebbe essere difficile reisolarli, se desiderato.     

Osservazioni sulla sessualità di ceratonia siliqua L.

Summary

In Ceratonia Siliqua the development of the female gametophyte is of the normal monomegasporial, eightnucleated type. The albumen is nuclear. The microspore tetrads divide simultaneously.     

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.     

Sul trasporto dei glucidi nelle piante superiori: I. — Aspetti biochimici

Abstract

CARBOHYDRATE TRANSLOCATION IN HIGHER PLANTS. I. - BIOCHEMICAL ASPECTS. — The concentration of soluble sugars and of hexose phosphates and the activity of several enzymes involved in hexose activation and polysaccaride synthesis have been investigated, separately, in the phloematic tissue and in the medullar parenchyma of Cucurbita Pepo internodes.

In the phloematic tissue (including sieve tubes, companion cells and phloematic parenchyma) the concentration of free hexoses appeared of about 50% lower, and that of glucose-6-P and of sucrose of about 100% higher then in the medullar parenchyma. Consistent amounts of raffinose were found only in the phloematic tissue. Paper chromatograms of the sieve tube exudate showed the presence of raffinose and sucrose in a ratio close to unity, and no appreciable amounts of free hexoses.

Determination of enzyme activity on preparations obtained from homogenates from the two types of tissue by repeated ammonium sulfate precipitation showed in the phloematic tissue a high activity of the enzymes hexokinase, UDP-kinase, UDPG-pyrophosphorylase and inorganic pyrophosphatase. The presence in the same tissue of galactosekinase, UDP-Gal-pyrophosphorylase and UDPG-epimerase was also ascertained.

On a protein basis, the activity of UDPG-pyrophosphorylase, inorganic pyrophosphatase and hexokinase appared about 3 times higher in the phloematic tissue than in the parenchyma; while this difference between the two tissues was not so marked for phosphofructokinase, and very small for other enzymes such as ATP-ase and phosphomono-esterase.

These results suggest that the very high activity, in the phloem cells neighbouring the sieve tubes, of the enzyme system catalyzing oligopolysaccaride synthesis could be an important component of the mechanism involved in the accumulation of oligopolysaccarides in the sieve tubes, and thus in sugar translocation. A scheme is proposed according to which the ATP and UTP energy would be utilized by the phloem cells to reach and to maintein a concentration of soluble sugars consistently higher than that prevailing in the contiguous tissues.     

Le Infezioni Con “Stubborn” Ottenute per Trauma E Il Grado di Recettività dei Tipi di Grano

Abstract

Dioecy ensures cross pollination but pollen must travel from male to female plants, sometimes covering long distances. The present study concerns the reproductive strategy of two Italian dioecious plants: Mercurialis annua L. and Bryonia dioica L. The former is anemophilous and the latter is entomophilous; the latter has nectar and pollen as rewards. The distribution of pollen grains on the stigma is very different in the two species, reflecting the different types of pollination. In both species there is a number-dependent mechanism of pollen germination on the stigma. This mechanism could enhance male gametophytic competition.     

Contributo allo Studio delle morfosi che si riscontrano sui Serpentini (possibilità di chemiomorfosi)

Summary

The ?. takes in consideration the chemical composition of Stachys recta var. serpentini ashes, taken from the serpentine substratum of Monte Ferrato near Florence to compare it to Stachys recta typica, taken from Monte Rinaldi near Florence; besides the structure and composition of their substrata. He points out the greater quantity of Mg and Ni in Stachys recta var. serpentini and its substratum than in Stachys recta typica and its substratum. Lastly he notices that clorures and sulphates are in a superior quantity in the serpentine soil than in normal soil, while in some other cases the contrary has been related (see Novak). So that the A. believes that the Mg and Ni quantity, caracteristic differentieting the two plants and their substrata, has a determined importance for the porpuse of the serpentine morphosis.     

Un antico relitto atlantico ai piedi delle Alpi Apuane: Trichomanes speciosum Willd., entità nuova per la flora italiana

Abstract

An Atlantic relict on the Apuan Alps: Trichomanes speciosum Willd., new to Italy.—In Versilia, at the foot of the Apuan Alps, has been found the fern Trichomanes speciosum Willd., new genus for the Italian flora and old relict witness, like Hymenophyllum tunbrigense (L.) Smith, of an Atlantic climate which still persists in deep valleys, dug on paleozoic quartz schists, on the tirrenic coast of the Apuan Alps.