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1.
The colonial and multicellular members of the Volvocales can be arranged in order of increasing size and complexity as the “volvocine series.” This series is often assumed to reflect an evolutionary progression. The flagellar apparatuses of previously examined algae are not consistent with a simple lineage. The flagellar apparatuses of Astrephomene gubernaculifera Pocock, Gonium pectorale Müller, Platydorina caudata Kofoid, Volvox rousseletii G. S. West, and V. carteri f. weismannia (Powers) Iyengar differ from one another, and there is no apparent progression inflagellar apparatus features from the simple to complex colonial forms. We examined the flagellar apparatuses of Volvulina steinii Playfair, Eudorina elegans Ehr., and Pleodorina illinoisensis Kofoid and found them to be similar to one another. The basal bodies are connected by a distal fiber that is offset to the anti side of the cell. Two microtubular rootlets originate on the inside of the basal bodies and extend toward the syn side. The other two rootlets are oriented perpendicular to the first two and are anti-parallel to each other. A coarsely striated component underlies the four-membered rootlets and extends to the basal bodies. A proximal fiber complex connects the two basal bodies. This complex consists of a branched striated component on the cis side of each basal body. One part extends toward the anti side of the cell, while the other extends into a fibrous component that runs between basal bodies. An additional structure extends in the anti direction from the trans side of each basal body. A fibrous component extends past one basal body in all four species. This component goes past the trans basal body in Volvulina steinii and the cis basal body in E. elegans and P. illinoisensis. The flagellar apparatuses of these organisms are similar to those of G. pectorale and Volvox carteri but different from the other colonial volvocalean algae examined. The algae examined in this study plus G. pectorale and V. carteri probably share a common evolutionary history that postdates the transition from the unicellular to colonial habit. Such a shared evolutionary history is a requirement of the volvocine hypothesis. However, we have not observed progressive changes in the flagellar apparatus correlated with increasing cell number, differentiation, and sexual specialization. Thus, it is possible, but not certain, that G. pectorale, Volvulina steinii, E. elegans, P. illinoisensis, and Volvox carteri may form part of a volvocine lineage.  相似文献   

2.
3.
Abstract

Flora of Popoli's gorges (Central Italy). — The results of floristic research developed from 1967 to 1969 at the Popoli's gorges (province of Pescara, in Abruzzo, Central Italy) are reported. Short accounts on the geographic position, on the geology and climate of the gorges are given, together with the floristic index of 696 entities, 4 of which are new for Abruzzo. For each species the biological and the phytogeographical categories are indicated; and for the whole of the flora the biological spectrum. This shows that this flora is a submediterranean one, with altitude influences. Critical remarks are developed about the taxonomy and distribution in the region of Abruzzo of several species wich looked particularly significant to the author.  相似文献   

4.
Astrephomene gubernaculifera Pocock is capable of growth on sodium acetate, even in the absence of light. From an evolutionary standpoint, it would be beneficial for this motile heterotrophic organism to be able to sense and swim to such an energy source. We used three assays to test for chemoattraction of A. gubernaculifera. In each case, there was strong chemoattraction to acetate. Propionate, a molecule structurally similar to acetate, also elicited a strong chemoattraction response, even though it was incapable of supporting growth in the dark in this strain. This implies that chemoattraction in A. gubernaculifera is based on a receptor‐mediated signaling response. Video analysis of colonies exhibiting the attraction response indicated that most of them remained motile in the vicinity of the acetate. This rules out the simplest possible model for accumulation in which colonies stop when they encounter increased acetate concentrations. We also tested a variety of other organic molecules for their ability to chemoattract A. gubernaculifera. Of the 11 sugars, 18 amino acids, and three other organic molecules tested, only the amino acid phenylalanine elicited chemoattraction.  相似文献   

5.
SYNOPSIS. The structure and certain aspects of the physiology of the sexual cycle, including mating and zygote germination, were studied in strains of the colonial green flagellate Astrephomene gubernaculifera. Mating type inheritance was analyzed in 4 crosses among strains with 7 chromosomes and 1 cross between strains with 4 chromosomes. Results in all cases indicated that mating type was under the control of a single pair of alleles. Twenty-six morphologically identical clones from separate geographic areas were studied with regard to sexual compatibility. On the basis of intercrossing, 6 sexually isolated groups were recognized. Complete gene flow (genetic compatibility) was found among the strains comprising intercrossing Group I.  相似文献   

6.
SYNOPSIS. A comparative physiologic study of 4- and 7-chromosome strains of Astrephomene gubernaculifera was done. The vitamins p-aminobenzoic acid, nicotinamide, biotin, thiamin HCl and vitamin B12 were tested for their ability to support growth. Only vitamin B12 was required for active growth altho the presence of thiamin HCl was necessary to produce structurally typical colonies. Astrephomene will not grow in the absence of an exogenous source of carbon. Of the 36 carbon sources tested, only pyruvate, butyrate, succinate and acetate permitted active growth. Sodium acetate was the best. Strains grew within the initial pH range of 5.0–7.5. At pH values above 8.0 growth declined rapidly. When media were buffered with TES (N-tris [hydroxymethyl]methyl-2-aminoethane-sulfonic acid) at an initial pH of 6.8 growth was enhanced. The organism grew at 15–40 C. Growth in the dark was slightly less than that in the light.  相似文献   

7.
Abstract

A new entomogenous Ascomycete found in cave: Cordyceps riverae.—A new species of entomogenous Cordyceps, belonging to Subgenus Racemella (Ces.) Sacc., found on an adult Lepidotteron in a cave near L'Aquila (Abruzzo, Italy) is described. The characters of this species, named Cordyceps riverae, are compared with those of other similar species of Cordyceps.  相似文献   

8.
The genus Meira Jacquelin du Val 1852 is revised, four lectotypes and a neotype are designated, a new synonymy is proposed and four new species from France – one from Alpes-Maritimes (Meira alpina n. sp.), two from Var (M. echinoides n. sp. and M. teloniensis n. sp.), one from Vaucluse (M. germanni n. sp.) and one from Italy, from Abruzzo (M. osellai n. sp.) are described,. Synonyms, bibliographic and ecological data are provided. Whole-body photos of the types of the old species and of the four new species, drawings of systematically important characters, keys and distribution maps are also presented.  相似文献   

9.
Lang, Norma J. (U. Texas, Austin.) Electron microscopy of the Volvocaceae and Astrephomenaceae. Amer. Jour. Bot. 50(3): 280-300. Illus. 1963.—Clonal cultures of Gonium sociale, G. pectorale, Pandorina morum, Eudorina elegans, Eudorina sp., Volvulina steinii, V. pringsheimii, Platydorina caudata, Pleodorina illinoisensis, P. californica, Volvox aureus, V. tertius, V. globator, V. barberi, and Astrephomene gubernaculifera representing the Volvocaceae and Astrephomenaceae in the Volvocales were examined with the electron microscope and their ultrastructure compared. The ultrastructure of the various organelles is basically similar in the species studied and no increase in cellular complexity is found to accompany the evolutionary trends evidenced in the Volvocaceae. The ultrastructure of a colonial cell is basically that of Chlamydotnonas. A cytoplasmic membrane having a unit membrane structure encompasses a cell and is continuous with the double-membraned flagellar sheaths. The flagella contain the typical 9 + 2 fibril arrangement with the 2 axial fibrils terminating in a cylinder at the flagellar base and the 9 peripheral pairs continuing into the cytoplasm as a basal body. The organelles comprising the cytoplasm are: mitochondria with plate-like cristae; dictyosomes composed of stacks of agranular cisternae; small, rough or smooth-surfaced vesicles; an endoplasmic reticulum of granule-bearing and agranular tubules, lamellae and broad cisternae; vacuoles which are either contractile, contain fine granular and fibrillar material, or have dense contents probably representing polyphosphate; lipid bodies; and dense granules 100–150 A which have been called ribosomes. The finely granular nucleoplasm is surrounded by a porous, double-membraned nuclear envelope and contains a centric nucleolus composed of dense, spherical granules. The outer membrane of the nuclear envelope bears granules and may have granular extensions into the perinuclear cytoplasm. Each extension appears to encompass one or several dictyosomes and has been termed an “amplexus.” The amplexi are agranular on the surface contiguous to a dictyosome. A double-membraned chloroplast envelope is continuous around the single, cup-shaped chloroplast. The basic chloroplast units are discs closed at each end, occurring in stacks of varying number parallel to the envelope. The presumed proteinaceous matrix of the basal pyrenoid is penetrated by elongated, tubular elements which connect with the lamellar discs. Multiple rows of granules, associated with individual discs, form the anterior stigma within the chloroplast envelope. The colonial matrix is not a structureless, mucilaginous material uniting the cells in colonies, but it has rather a highly complex structure especially around the periphery of the colony and the flagellar channels. The apparent substitution of a fibrillar layer of the colonial matrix for the discrete compact cell wall, such as is found in Chlamydomonas, implies a greater degree of complexity in the evolution of these colonial genera than is generally assumed.  相似文献   

10.
Summary A new species of Volvulina, V. pringsheimii, was isolated from Texas. This species differs from the well-known species of Volvulina, V. steinii, in having pyrenoids in the vegetative cells, a common gelatinous envelope surrounding the colony, a protoplasmic protrusion on the anterior end of each gamete, and spines on the secondary wall of the zygospore.This paper is dedicated to Professor Dr. E. G. Pringsheim on the occasion of his 80th birthday.  相似文献   

11.
We use a geodatabase to investigate the distribution patterns of an important subset of floristic reports recorded for the Parco Nazionale delle Foreste Casentinesi, Monte Falterona, Campigna in the northern Apennines, Italy. This database was analysed using spatial statistical techniques and a digital elevation model. Significant relationships between species presence, sampling effort and species richness were then analysed in relation to topographical variables and to an existing vegetation map. Report-based rarefaction techniques were used to compare areas having different numbers of species recorded. Overall, the analysis shows that some areas of the park are richer in species of conservation interest than others, and that these have been more intensely investigated. Meanwhile, for other areas, botanical knowledge is scarce or even absent. This has led to clustering and redundancy of floristic data in some areas. The study confirms that the existence of a complete and up-to-date geodatabase creates a valuable resource which enables information gaps to be bridged. Such gaps often exist in biological databases for rare and narrowly distributed species. The wider application of these analyses should also give useful indications of how the incidences of these species of conservation interest are associated with particular environmental variables.  相似文献   

12.
Riassunto

L'A. studia N. 87 entità di licheni raccolti nell'A. O. I. da ufficiali della Milizia Nazionale Forestale. Fra essi ci sono nuove per la scienza due specie: Chaenothecopsis africana, Theloschistes Sennii e 8 fra varietà e forme; molti sono nuovi per l'A.O.I. e per il Continente africano.  相似文献   

13.
14.
One hundred sixty one soil samples from the Parco Nazionale d'Abruzzo were analyzed. The keratinophilic fungi present in the soil samples were isolated and classified with the hair-bait method. The most common was T. ajelloi (28.6% of the total samples) followed by Chrysosporium keratinophilum (14.3%), C. sp. (11.2%), C. asperatum and Trichophyton sp. (6.8%), T. terrestre (5.6%), C. pannorum and C. state of Ctenomyces serratus (3.7%), C. tropicum (3.1%), M. cookei (2.5%) and the C. state of Arthroderma tuberculatum (1.9%). Other species, not belonging to the dermatophytes, were also isolated. The absence of dermatophytes was correlated with low human and animal population density.Altitude and vegetation did not seem to influence their distribution.  相似文献   

15.
Summary

The Author discovers and describes a new station of Stipa trichotoma Ness (Nassella trichotoma Hackel) in the «Selva di S. Rossore » (Pisa), where it represents an adventitious and probably newly naturalized species for the Tuscan Flora.

The Author refers on the preceedind foundings of this south-American plant in Italy, discussing the complicated sinonimy, and points out the opportunity for the constitution of-a new section Nassellopsis and the interest to include the species in the new edition of «Nuova Flora Analitica d'ltalia» of Adriano Fiori.  相似文献   

16.
Abstract

Germination and growth of ABIES ALBA mill. in different light and temperature conditions. — The results of a research on white fir from different localities are summarized as follows:

a) Germination of seeds from three italian localities (Tuscany, lat. 43°, 44'; Abruzzo, lat. 41°, 52'; Calabria, lat. 38°, 33') has been tested in several ecological conditions (temperature, light and chilling); it has been found that 22 °C, 8 hrs. of light and a 3 weeks prechilling at 5 °C, are stimulating conditions for all the seeds. The Cala-brian seeds seem the most reactive.

b) Growth in different photoperiodic conditions has been tested on seedlings from the Appennine, from France (lat. 49°, 10') and Poland (lat. 49°, 39'). Growth is evidently stimulated by long-day conditions in all the seeds experimented and growth acceleration touches its maximum in the Calabrian seedlings, provided they germinated at 12°C in the ligth.

It has been concluded that Calabrian Abies behaves as a Biotype, evidently distinguished from all the others, and an ecological explanation of this behaviour has been attemped.  相似文献   

17.
Abstract

Annual cycle of phytoplankton in the coastal waters of the « Parco Naturale della Maremma ». II. Flora and communities variations.—The hydrology of the marine coastal area of the Parco Naturale della Maremma and the annual cycle of phytoplankton standing crop have been examined in a preceding paper (Lenzi Grillini e Lazzara, 1978). In the present paper the species list and the main features of marine phytoplankton communities of the same area are reported as a result of an annual cycle of monthly collections effected in seven stations. The most conspicuous seasonal bloomings are due to Skeletonema costatum (Grev.) Cleve in February and to some species of the Chaetoceros gen. in November; the dinoflagellates play a minor role throughout the year, except for Gonyaulax minima Matz. with a light blooming episode in summer. The annual cycle of bottom living diatoms found in the samples appears to be very similar in its shape to the cycle of the pelagic species, as for the standing crop and for the species number. The community structure variations have been analyzed by means of diversity and dominance indexes and of species frequency diagrams. As it concerns the differences in species composition among the seven stations, the area in front of the rocky shore, with deeper and more saline waters, appears to be very homogeneous, whereas some differences have been observed in the shallow waters, in front of the sandy shore and under the influence of the Ombrone River mouth.  相似文献   

18.
Parastenocaris lorenzae n.sp. is described from rhithrostygal of the Sangro river (Abruzzo, Central Italy). Parastenocaris glacialis Noodt, 1952 is for the first time recorded from Italy. The presence of borealpine elements in ground waters of Central Apennines is briefly discussed.Contribution to the knowledge of the groundwater fauna in central Research supported by grants from M.P.I. (40%) and C.N.R. (Gruppo and southern Italy: XLIV. Nazionale di Biologia Naturalistica).  相似文献   

19.
A nematode parasitic of bronchial system of Rupicapra rupicapra (chamois) of Parco Nazionale del Gran Paradiso (Italian Western Alps) is described and the name Protostrongylus (Protostrongylus) rufescens boevi subspecies nova, is proposed.  相似文献   

20.
Huit espèces de Lasioglossum sont inventoriées de Nouvelle-Calédonie. Un nouveau sous-genre cleptoparasite endémique, avec une nouvelle espèce, Lasioglossum (Parachilalictus n. subg. ) neocaledonicum n. sp., est décrit. Les espèces endémiques suivantes du sous-genre Chilalictus sont nouvelles : Lasioglossum (Chilalictus) alticola n. sp., L. (C.) tchambae n. sp. et L. (C.) webbi n. sp. Une nouvelle sous-espèce, Lasioglossum (Chilalictus) polygoni austrocaledonicum n. ssp., est décrite de Nouvelle-Calédonie et d'Australie. Les espèces australiennes L. (Chilalictus) lanarium (Smith 1853) et L. (C.) instabilis (Cockerell 1914) sont découvertes pour la première fois en Nouvelle-Calédonie. Lasioglossum (Parasphecodes) sulthicum (Smith 1853) est la première espèce de ce sous-genre australien signalé en Nouvelle-Calédonie. L’émergence du parasitisme et la spéciation en condition insulaire font l'objet d'une discussion. Le cleptoparasitisme du nouveau sous-genre Parachilalictus n. subg. peut être établi en examinant un ensemble de caractères morphologiques convergents chez les groupes parasites de Halictidae dont les principaux sont la réduction de la brosse collectrice de pollen sur les pattes postérieures et l'aplatissement de la quille du labre. La forte ressemblance de Parachilalictus n. subg. avec les espèces de Chilalictus endémiques de Nouvelle-Calédonie et son absence en Australie suggère une spéciation locale et récente. Les deux nouvelles espèces endémiques décrites dans le sous-genre Chilalictus et dont Parachilalictus n. subg. pourrait avoir émergé ont une distribution montagnarde (L. alticola n. sp. , L. tchambae n. sp.). Dans le complexe L. polygoni (Cockerell 1929), la spéciation s'exprime par la variation de la densité et la force de la ponctuation. A basse altitude et le long de la côte ouest plus sèche, on trouve la sous-espèce typique polygoni. A des altitudes variant de 5 à 1150m, il existe clairement deux autres sous-espèces. La nouvelle sous-espèce austrocaledonica ne se trouve que dans la partie sud de l’île, en milieu ouvert de « maquis » tandis que la sous-espèce delobeli Pauly & Munzinger 2003 a une distribution plus étendue sur les massifs montagneux de la partie est, et a été rencontrée essentiellement le long de pistes forestières en forêt dense humide. Cette dernière sous-espèce habite aussi l'Australie.  相似文献   

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