Comportamento Di Un Carattere Teratologico Comparso in Navicula Minima Grun

Abstract

Behaviour of a teratological character present in «Navicula minima» Grun. — A teratological form with curved cells like the kidneys has been isolated from a culture of Navicula minima Grun, to follow the behaviour during the biological cycle. Alternately varied cells in the morphology of the frustules appeared in the descendants, deriving from a modification more or less evident in the initial teratological character. The main cause of this phenomenon can be found in the normalization process of the frustules that has been put in relation to a probable plasticity of the cellular Silicon walls. The cells, even though more or less deformed, have given origin to auxozygotes which, having terminated their growth, have formed perfectly normal frustules.     

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.     

Sulla Presenza di Ificellarioli e di Conidi in Mieobionti Lichenici Coltivati in « Vitro ». Riassunto

Abstract

On the presence of « hyphycellariola » (swollen celles) and conidia in three lichenized fungi cultivated « in vitro ». — The Authors refer to the presence of « cellariola » (and « hyphycellariola ») found in pure cultures « in vitro » of the mycobiont of Xanthoria parietina and describe the morphology of conidia in the fungus isolated from Sarcogyne similis and Acarospora fuscata.

As far as the « cellariola » and « hyphycellariola » are concerned, it is the first note relative to the mycobionts of Lichens.

The Authors report the data of the utilized medium and the morphological observations.

This previous studies will be intensified by further research.     

Ulteriore contributo alle conoscenze sul « Denti de cani » (X Haynaldoticum sardoum Meletti e Onnis)

Abstract

Further data on « Denti de cani » (X Haynaldoticum sardoum Meletti e Onnis). – The authors defin the taxonomic position of « Denti de cani » (X Haynaldoticum sardoum Meletti e Onnis). It is characterized by the presence of two forms differentiated for morphological features and behaviour.     

ULTRASTRUCTURE OF THE FILAMENTOUS HABIT IN THE DIATOM NAVICULA CONFERVACEA (KÜTZ.) GRUN.1

Frustules of the filamentous diatom Navicula confervacea (Kütz.) Grun. are united by the overlapping of marginal teeth located alongside the junction of valve face and mantle. Scanning and transmission electron microscopy show this connecting mechanism to differ from the previously reported inter-digitating spines or teeth in the genera Melosira, Stephanodisus, and Fragilaria.     

Insediamento e Diffusione di Buddleia Davidii Franch

Abstract

«Buddleya davidii» in «Valtellina» (North Italy), its settling and diffusion. — Vegetational areas where «Buddleya davidii» is naturalised in Valtellina are described and the subsequent phases are followed through 18 years.     

Protoplast Rotation, Cell Division and Frustule Symmetry in the Diatom Navicula bacillum

Navicula bacillum frustules, like those of many other naviculoiddiatoms, exist in two forms, cis and trans, which occur in theratio 1 cis: 2 trans. During interphase the protoplast bearsa constant relation to the orientation of the hypovalve, suchthat the nucleus lies on the same side as the first-formed halfof the hypovalve. Immediately before mitosis the plastid andnucleus migrate around the cell until the nucleus lies on theopposite side from its interphase position, where it then divides.After cytokinesis the new valves form with their primary halveson the same side as the recently divided nuclei. This and the180° rotation of the protoplast during the cell cycle explainthe 1 cis: 2 trans ratio. Navicula bacillum Ehrenb., cell symmetry, diatom systematics, plastid structure, protoplast rotation     

Sulla Terminologia dei Processi Apomittici

Summary

The Author observing the great disagreement of the terminology usually adopted for the apomictic phenomena, examines the whole series of the phenomena noted both in regards of the formation of the gametophyte and of the embryo. The forming of the gametophyte is fixed on the base of nature of its original cell, normally a haploid spore or »haplospore« (phenomenon of the »haplospory« following the regular meiosis), rarely a diploid spore or »diplospore« (phenomenon of the »diplospory« following the irregular meiosis, as for instance in the case of restitution nucleus, etc.). The original cell can be at least represented by the same cell that usually is the spore mother cell, whether for the outward causes, or for inward causes is lacking the usual reductional process. For the failure of the meiotic process, such a cell cannot be called »spore«.

A cell of the somatic tissue of the sporophyte can even become the original cell of the gametophyte always in case of the absence of the meiosis. These two last cases of apospory are respectively called: »somatic apospory« and »gonial apospory« (= germinal apospory) (Chiarugi 1926).

The formation of the embryo is fixed on the base of the nature of the fecundation. The principal phenomena of the fecundation are represented by the following cases: »amphigamy« (or eugamy, or gamy), »semigamy, »pseudogamy«, »apogamy« »parthenogenesis«. The A. uses the term »apogamy« both for the diploid eggs and for the haploid eggs in which the stimulation of the division is produced by the pollen-tube or by male nuclei, in absence of the gamy.

The term »parthenogenesis« is restricted to the division of the haploid or diploid eggs in which the stimulation is not caused by pollen-tube nor even for the great reason, by the male nuclei existing in it.     

Cadmium decontamination and reversal potential of teratological forms of the diatom Planothidium frequentissimum (Bacillariophyceae) after experimental contamination

While the induction of teratology by cadmium (Cd) on diatoms is already known, reversal kinetics are not well documented. This study aims to understand the viability of diatoms exhibiting teratological frustules and their reproduction capacities within a Cd‐impacted population to predict their return to normal diatom forms. We worked on a frequently encountered species in French hydrosystems: Planothidium frequentissimum (Lange‐Bertalot) Round & L. Bukhtiyarova. First, a 21‐d contamination phase highlighted increasing inductionof different teratological types in response to two levels of Cd contamination: 20 and 100 μg · L^?1. The deformity counting indicated that Cd firstly generated striae and mixed teratologies, then affected the central area and the valves. Second, a 28‐d decontamination phase demonstrated the Cd depuration capacity of Planothidium frequentissimum. Cd half‐lives appeared relatively low, ~6 d for the 100 μg · L^?1 condition. Moreover, the decontamination phase showed a decrease in teratology abundances, but a still incomplete recovery after 28 d. Deformations of the striae appeared to be the most sustainable phenotype since they were still significantly higher than in reference cultures at the end of the decontamination phase for both Cd cultures.     

Osservazioni sugli stadi iniziali della morfogenesi in coltura di alcune specie del genere Peyssonnelia Decaisne

Abstract

Researches on the morphogenesis of the genus Peyssonnelia Decaisne. — This paper reports the first result on morphogenetic researches in cultures of 3 species of the genus Peyssonnelia Decne. The development of Peyssonnelia rubra (Grev.) J. Ag. is of «Dumontia type »(CHEMIN, 1937) that one of Peyssonnelia squamaria (Gmelin) Decne. and of Peyssonnelia inamoena Pilger of «Naccaria type». According to our cultures results the morphogenesis of genus Peyssonnelia is of two type. Sample of P. squamaria and P. inamoena are collected in the gulf of Trieste (Nord Adriatic Sea) those of P. cfr. rubra in the Morlaix Bay (English Channel). Taxonomic value of the results are discussed.     

“Eumeiosi” e “Meiosi Apoomeotipica” Seguita da “Mitosi a Diplounivalenti” Nel Tessuto Somatico di Sambucus

Summary

The Authors describe in Sambucus nigra L the occurrence of the » apohomeotypic teiosis « followed by a »mitosis with diplounivalents « (Battaglia 1945, 1947) in ae somatic tissue of the style. The AA. observed also the occasional formation f four haploid nuclei and then the occurence of the »eumeiosis« (Battaglia 1945).     

Sulla penetrazione di Penicillium digitatum Sacc. e Penicillium italicum Wehmer nei frutti degli agrumi

Summary

The A., with a series of controls and investigations, accomplished on different groups of Oranges and following various forms of artificial infection with Penicillium digitatum and Penicillium italicum, renders evident the different reactions that these moulds have with regard to the resistance of the cuticle and the epidermic and under-epidermic stratums of the peel of the controlled fruits. Moreover the A. confirms that both the P. digitatum and the P. italicum can act as «parasite of injury» and as «parasite of contact».     

Identity and typification of Navicula hasta (Bacillariophyceae)

The name Navicula hasta is regularly applied to large, heavily silicified Navicula specimens with lanceolate outlines, protracted ends, and relatively coarse, radiate, and lineolate striae that are more irregularly spaced around the central area. As such, Navicula hasta has been reported from numerous localities such as brackish water fossil sediments, oligotrophic ancient lakes and postglacial lakes. When the data for distribution of Navicula hasta are summarized, this species appears to be geographically and temporally widespread with a broad range of ecologic tolerances. Published reports for size range show that diatomists during the last century have differing concepts of the species starting with the disagreement between the protologue and one of the figures given by Pantocsek. Furthermore, an informal ‘type’ of Navicula hasta reported in 1980 does not match the protologue and is not unambiguously based on material Pantocsek had in his hands when describing his new species. We studied published reports of Navicula hasta and investigated material reported to contain Navicula hasta and its allies from the type locality (Köpecz), one of the fossil deposits reported to contain N. hasta (Bodos) and from ancient and other younger lakes worldwide. From our analyses, we document the variation and underappreciated diversity within the Navicula hasta group and set the stage for formal recognition of new species in subsequent papers. Herein, we formally propose a lectotype from among the original illustrations and designate an epitype for Navicula hasta based on Pantocsek's Köpecz material. Additionally, two new species, Navicula krenneri spec. nov. and Navicula pseudohasta spec. nov. are described and a lectotype of Navicula superhasta Lange‐Bertalot and Metzeltin is proposed.     

Crepis Bursifolia L., Nuova Stabile Inquilina della Flora Ligustica della Riviera di Ponente

Abstract

«Crepis bursifolia » L., new permanent tenant of the flora in west ligurian coast. — The author declares the permanent presence of « Crepis bursifolia » L. in Liguria, and informs about new stations of this species along the western riviera. The relates, furthermore, the unfavourable results of his close investigation to verify the eventual presence of further station of « C. bursifolia » L. found by former researcher.     

Saxifraga Berica (Béguinot) D. A. Webb E Asplenium Lepidum Presl Sui Colli Berici

Abstract

«Saxifraga berica» (Béguinot) D. A. Webb and «Asplenium lepidum» Presl on the «Colli Berici». – We have identified a new association in the small caverns of the calcareous rocks in the hills of the north-eastern zone of the «Colli Berici», rising from the Italian plain near Vicenza. We have adopted for this association the name: ADIANTO-SAXIFRAGETUM BERICAE. This phytocoenose is characterized by the endemic «Saxifraga berica». We have found new stations of this remarkable plant and reported some features of this species to complete the diagnosis of D. A. Webb. In two station of this association we have found also the rare «Asplenium lepidum», new for this region.     

Le Piante e la Musica. Riassunto

Abstract

The Plants and the Music. — The valuable contribute that the Biology may offer to the scientific study of the « essence » of the Music is pointed out. The plants as Animals and as remotest ancestors of the humanity, contribute to form what the A. calls the « Promusic », that is the natural and necessary starting-point of the evolution of the Music, which is exclusive work of the man. The Plants particularly, although indirectly, showing wonderful instances of transformations and associations of simple in complex forms, as well of colours and scents, have certainly inspired to the Man the Harmony, which is just in Music the Art, unknown to the Ancients, in associating aesthetically sounds and timbres.     

Nuovi Dati Sulla Distribuzione Di Isoétes Malinvernianum in Lomellina

Abstract

New data on the distribution of « Isoëtes malinvernianum » in Lomellina. — The Author relates the discovery of many new stations of Isoëtes malinvernianum in Lomellina (Province of Pavia). Many observations carried out in these new localities and in the most part of the already recorded localities near Novara and Vercelli have allowed him to modify some convincements on the habitat of this well known endemism. So he reports that Isoëtes malinvernianum vegetates not only in the waters of « fontanile » but also in waters of the most different sources, that this species is not solitary but accompanied by many species as Callitriche palustris, Fontinalis antipyretica, Sagittaria sagittifolia, Vallisneria spiralis, Potamogeton crispa and few other species more. Isoëtes malinvernianum, besides, is not damaged by dredge works in the canals and is present not only in morainic soils and in the diluvial soils transformated in ferreto but also in the terraced flood named with old terms as « Terrazziano » or « Diluvium recente » and in the diluvial soils of the « Alluvium ». Now at least it is not possible to ascribe plant communities of which Isoëtes malinvernianum makes part to a well defined association.     

Ricerche Cariologiche e Embriologiche Sul Genere Rudbeckia (Asteraceae)

Summary

The author describes the different modalities of the cellularisation of the adult gametophyte of Rudbeckia laciniata L. The several cases are arranged according to the number and the type of differentiation of the cells of the gametopyte. Of each type it is stated the frequency, calculated in about 500 cases.

The author remarks that the differentiation of the single cells is owing to »an effect of the position«, which exists in the displacement of the nuclei of the gametophyte regarding the proendospermatic cell, to which cell, however, one can attribute a pre-eminent »power of organization«. The displacement of the nuclei is after all the consequente of the stage of the » polarisation «.     

Osservazioni Anatomiche Su Una Forma Teratologica Di Tulipa Orientalis Levier

Abstract

Anatomical observations upon a teratological form of TULIPA ORIENTALIS Levier. — The author illustrates a singular case of abnormal concomimitances in Tulipa orientalis Levier, which hears six flowers on the same scape: three of these flowers are disposed in a terminal « bouquet » and three at different heights in the scape.

Almost all the pistils of these flowers were tetracarpellate; one of them being greatly hypertrophic in respect of the others, and completely devoided of ovules.

Very interesting for its rarity and here observed for the first time for the Tulipa genus, is the presence of a very small and almost perfect supernumerary tetracarpellate pistil, joining the normal pistil of one of the terminal flowers, and the origine of which can't be ascribed to a simple scission, but only to an evident case of multiplication as the two pistils appear distinctely independent.