Osservazioni Sul Meccanismo Di Conversione Della Energia Luminosa In Energia Chimica Nel Processo Fotosintetico

Abstract

Contribution to the knowledge of the mechanism of light energy conversion into chemical energy during the photosinthetic process. — A general scheme for the pathways of electron transport in chloroplasts is discussed, in the light of the recent evidence for the existence of cyclic photophosphorylation in vivo. The possible function of cytochrome f is discussed.     

Reazioni Metaboliche All'auxina - VII Variazioni a Carico Di Metaboliti Della Glicolisi

Abstract

Metabolic responses to auxin. VII. Effects on glycolysis. — The detection of changes the of level of respiratory substrates could provide an indication on the site of action of auxin. The effects of indoleacetic acid on the contents in several glycolysis intermediates in isolated segments from the growing part of the third internode of etiolated pea seadlings were thus investigated.

Hexose phosphates, triose phosphates, phospho-enol-pyruvate, pyruvate and ethanol were determined enzymatically in the neutralized perchloric extracts from groups of segments incubated for 3 hours in the presence or in the absence of 5 × 10 ^?5 M indoleacetic acid. No significant difference appeared between the results on the perchloric extracts and those obtained after fractionation with barium and alcohol, according to Umbreit et al.

Acetaldehyde was measured as by Klotz. Pyruvate was determined also as a phenyl-hydrazone, according to Cavallini and Frontali; the same method was used for the determination of α-ketoglutarare and of an unknown compound, showing a chromatographic behavior similar to that of an uronic acid.

Auxin induced a modest but significant increase of hexose-6-phosphates (16%) and of fructose di-phosphate (38%). For glucose-1-phosphate and triose phosphates — present at very low concentration — no significant changes could be detected, α-ketoglutarate level appeared unchanged. The compound behaving as an uronic acid increased, in the auxin treated segments, by more than 100%.

A very definite response to auxin appeared at the level of pyruvate. acetaldehyde and alcohol. Pyruvate quite reproducibly increased by 60%, and acetaldehyde production was more than doubled. In contrast, alcohol decreased by about 40%.

These results are discussed in relation to the previous data on the effects of auxin on the oxidative metabolism, and, particularly, to the findings of an increased rate of CO-sensitive respiration and of the rise of the ATP, TPNH and red. glutathione levels in the auxin treated pea internode segments.     

Le Osservazioni Fitofenologiche Della Rete Italiana Nel 1929 (Annata VIII)

Abstract

Correlative techniques for estimating environmental requirements of species – variably termed ecological niche modeling or species distribution modeling – are becoming very popular tools for ecologists and biogeographers in understanding diverse aspects of biodiversity. These tools, however, are frequently applied in ways that do not fit well into knowledge frameworks in population ecology and biogeography, or into the realities of sampling biodiversity over real-world landscapes. We offer 10 “fixes” – adjustments to typical methodologies that will take into account population ecological and biogeographic frameworks to produce better models.     

Osservazioni E Considerazioni Sul Fenomeno Della Micorrizia al Piccolo San Bernardo

Riassunto

L'A. espone i resultati di osservazioni compiute sul fenomeno della micorrizia, constatando fra l'altro che esso si attenua nelle piante alpine coltivate nella Chanousia rispetto a quelle spontanee dei dintorni. Enuncia l'ipotesi che i componenti di un'associazione vegetale sieno fra loro strettamente collegati a causa del considerevole sviluppo del micelio micorrizogeno, che può passare anche dalle radicì di una specie a quella di un'altra.     

Saggi Sul Comportamento Della Cellula Vegetale di Fronte al Reattivo di Schiff

Riassunto

Sono state fatte diverse prove per la reazione di Schiff, di Feulgen e di Bauer su tessuti vegetali. Diversi tipi di membrane, fra cui quelle lignificate, sono risultati Schiff positivi. I nuclei sono risultati Feulgen positivi, con l'eccezione dei nuclei del gametofito maturo di Crinum sp., i quali sono tutti Feulgen negativi, meno quelli antipodali. L'amido e tutte le membrane sono risultati Bauer positivi.     

Fitoplanctonti Raccolti in Occasione Della Moria di Pesci Verificatasi Lungo la Costa Marchigiano-Romagnola Nel Maggio 1969

Abstract

Phytoplankton collected during the fishes death occured off the western middle Adriatic coasts in May 1969. — A taxonomic inventory of some phytoplankton samples taken during a « red bloom » occured off the Italian Adriatic coasts from Cattolica to Cervia is given and discussed. The most common species was Peridinium depressum Bailey. It is also noticeable the presence of many Ceratium species and of Oxytoxum sceptrum (Stein) Schroder, a dinoflagellate rare for the Adriatic sea. The study of hydrological data and the comparison of this list with that of the species collected six days before, 50 miles southward, let us suppose that, for an anomalous circulation of waters with mediterranean characteristic, a stock of tipic pelagic species were transported very close to our coasts. Particular favourable conditions allowed big development of Peridinium depressum and its metabolism was responsible of the Oxygen deficency that was noted and was the cause of the fishes' death.     

Reisolamento di una rara specie di Lievito: Trigonopsis variabilis Schachner

Zusammenfassung Trigonopsis variabilis, bisher erst einmal isoliert (1929), wurde in einem Traubenmost aus dem Weinbaugebiet des Staates S. Paulo, Brasilien, wieder aufgefunden. Es wird sein morphologisches und physiologisches Verhalten unter verschiedenen Kulturbedingungen beschrieben.