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The present study aims to characterize the floristic diversity and the demographic structure of the woody groups of cork oak (Quercus suber L.) of the forest of Ouled Bechih (Souk Ahras). Floristic and dendrometric data were collected in four plots of 900 m² and regeneration was assessed. The flora inventory has identified 25 species belonging to 25 genera and 18 families. The Asteraceae family is the most common (20%), followed by the Fabaceae, Oleaceae and Rosaceae (8%). The other families include species that are very poorly represented (4%). The diameter and height structures show a concentration of adult individuals in all the stands. In the perspective of rehabilitation and sustainable management of forest ecosystems, this study provides additional information on the current state of cork oak stands in the Ouled Bechih forest. [ABSTRACT FROM AUTHOR]

As an eclectic scientist, Théodore Monod is well known for his works on deserts, crustaceans, fishes, botany, desert geology, archaeology, ethnology and the history of science. He was one of the first ecologists, protector of nature and life. He devoted himself to more than twenty scientific disciplines during his career. For many scientists he was the specialist of their own discipline, but in fact he was a specialist of many branches of natural sciences. His 100 publications in ichthyology constitute a remarkable body of work even if they represent only 5% of his writings. This written work is considerable: 2167 scientific articles, notes and books for the general public were published in about 80 years. It is therefore delicate to propose a selection that illustrate the eclecticism of their author. In this paper we concentrate on the works in ichthyology. As soon as he was appointed to the Museum in 1922, he was sent to Mauritania for a year to study fish and crustaceans and also their fishing. These two animal groups have always been his passion and his specialty in zoology. Anatomist, he knew how to observe, draw and interpret all the organisms he studied. The books he wrote alone or in collaboration have become references for all ichthyologists and carcinologists. Thanks to his "insatiable and devouring" curiosity of nature, throughout his missions at sea, his explorations of oceanic islands, he collected until the end of his life tens of thousands of samples. His entry, as an assistant, in a laboratory dedicated to overseas fisheries forced him to familiarize with both fish and tropical countries. The contribution of Theodore Monod to the study of fish and fishing was vast. His work concerns both the fundamental aspects and the applications of ichthyology and can be divided into six major themes: "Fishes and fisheries", "Systematics, phylogeny, biogeography", "Biology of fishes", "Anatomy and functional morphology", "Inventories and catalogs of species", "History of Ichthyology". Among his 100 scientific publications on fishes, we note some master works such as the "Contribution to the fauna of Cameroon" (1927), his work on "The fishing industry in Cameroon" (1928), his work on the systematics of Clupeidae (1961), the numerous anatomical studies on tropical species such as the balastids (1958 to 1960) and elopids. We also note his voluminous work on the urophore complex of the Teleosteans (1968), the work on the cephalic osteology of the Scaridae, started in Dakar 60 years before publication, and completed in collaboration in Paris (1994, 1997). Finally, it is essential here to mention the eminent role played by Théodore Monod in the launching of the series of regional Catalogues/Check-lists of fishes ("the Clof..."). The first of these catalogs, the Clofnam ("Checklist of the fishes of the north-eastern Atlantic and the Mediterranean, 1973"), in which he participated very actively as author and mainly co-editor, served as a model for the whole series. While remaining African at heart and in love with deserts, Théodore Monod remained faithful to the sea and to marine fishes, as much in the subjects of his research as in his scientific functions. [ABSTRACT FROM AUTHOR]

New records of alien plants escaped from cultivation in Algeria. — In this contribution are reported three vascular species new to the alien flora of Algeria and continental North Africa, reported outside the cultures in the Skikda region (northeastern Algeria). Duranta erecta and Justicia adhatoda are considered casual, Tecomaria capensis is considered naturalized. The latter is established in a relic of a maquis of Quercus suber and shows a significant potential for more spreading. Thus, T. capensis should be monitored to prevent a prompt potential invasiveness in Algeria. [ABSTRACT FROM AUTHOR]

A new pteridophyte for the Algerian flora: Isoëtes delilei (Isoëtaceae). — In the present work we report a new pteridophyte for Algeria: Isoëtes delilei, a species presents in France, Spain and Portugal, and recently discovered in Morocco. This species is on the world and national red lists in the countries where it is reported. With the only one station here reported, it is certainly a critically endangered species in Algeria, needing urgent protection measures. [ABSTRACT FROM AUTHOR]

A first investigation on the horticultural flora of the Annaba region (North-East Algeria): Biodiversity and socio-ecological interest. -- The present study was undertaken with the aim of improving knowledge and proposing a first checklist of horticultural plants present in public and private green spaces in the region of Annaba (northeastern Algeria). During the period from 2018 to 2021, a total of 164 taxa recorded. The results obtained are given in terms of floristic composition, forms of life, type of nativity and socio-ecological interest of the plants observed. However, the real impact of potentially invasive species on plant communities and ecosystems deserves urgent assessment with specific studies. [ABSTRACT FROM AUTHOR]

This article discusses the collaborative process that led to the conception of the exhibition Kuru. L'art d'un monde en mutation held in 2019 at the Botanical Garden of Neuchâtel, Switzerland. This project, which brought together San Naro artists from Botswana, anthropologists and museum professionals, aimed to rethink the museum's approach to contemporary San art and to develop more inclusive modes of exhibition. This article documents the strategies of representation of the Self and the Other mobilized in this context and proposes a reflection on the contributions, the stakes and the limits of this collaboration at the intersection of art, anthropology and botany. It highlights the unintended effects, constant adaptations, and persistent asymmetries at work in the exchanges, and discusses the value of making sense of these interactional dynamics within the museum space. [ABSTRACT FROM AUTHOR]

The dates and camel milk present the traditional staple dish among the populations of the south of our country. It is considered a rich and complete nutritional source. However, due to the high temperatures in these areas and the lack of refrigeration means, excess milk from camels is consumed in fermented form. The aim of this study is to assess the effect of fermentation and addition of date syrup on the physicochemical and microbiological quality of camel milk. The analysis of all samples of camel milk collected in the region of Ouargla, Algeria, are analyzed before and after fermentation with the addition of date syrup at different concentrations of 0%, 3% and 6%. Monitoring showed that fermentation leads to slow acidification over time, with maximum acidification for the 6% date syrup concentration. Nutritional quality is investigated by biochemical analyzes, which revealed a significant decrease in the levels of total dry matter, lactose and total proteins which went from 119.8, 43.6 and 32.4 respectively to the levels of 112.5, 25.3 and 28.0 g/l to T96H of fermentation. But the fat content has stabilized during fermentation, which is 36.6 g/l. The hygienic quality is investigated by microbiological analyzes, which have shown that the lactic acid bacteria exhibit maximum growth for the 3% and 6% concentrations in date syrup by comparing with the initial load. At the same time, this flora inhibits the growth of exogenous flora, either pathogenic or contaminant. These results indicate that the fermentation of milk by adding date syrup in moderate concentrations promotes the development of the lactic flora of camel milk and promotes the improvement of the hygienic and nutritional quality of camel milk. These results seem to be an asset for promoting local products. [ABSTRACT FROM AUTHOR]

Solanum rostratum (Solanaceae): a new invasive xerophyte for the flora of Algeria. - The authors report in this paper the presence of a new taxa for the Algerian flora. It is Solanum rostratum, an invasive plant well known for its high spreading capacity and a threat potential to natural and anthropogenic ecosystems. Some reflections resulting from this discovery are mentioned in particular the economic and ecological values of the plant as well as the threats linked to its possible spread across the country. [ABSTRACT FROM AUTHOR]

The Cape marigold (Arctotheca calendula): a new exotic species for the Algerian flora. - The authors report the recent discovery in Algeria of a xenophyte belonging to the Asteraceae. Arctotheca calendula, native to South Africa, was observed for the first time, in the northeast of the country (Oriental Numidia). [ABSTRACT FROM AUTHOR]

On the occurrence of Atriplex canescens (Amaranthaceae) in Algeria: ecology, taxonomy and biogeography. - Atriplex canescens var. gigantea is recorded for the first time for the non-native flora of Algeria. The description of the finding locality, taxonomic notes and detailed distribution are provided. [ABSTRACT FROM AUTHOR]

Through Anchomanes difformis (Blume) Engl. (Araceae), the present survey is a plea for the purposes of the valorization of the plants to purgative virtues of our native soil. The methanolic crude extracts of the rhizomes (ER) and of the binomial leaves-stems (EF) of this plant, were the subject of phytochemical investigatings by a bio guided approach. The phytochemical screening of EF and ER showed that A. difformis contains flavonoids, reducing compounds, alkaloids, sterols, terpenes, proteins, coumarins, catechic tannins, saponosides and quinones. The pharmacological survey achieved with EF and ER on the duodenum of rabbit, put in evidence that only ER manifests laxative properties. The qualitative analysis by TLC of the ethylic acetate excerpt (ER2) gotten from ER by liquid-liquid extraction, revealed the presence of secondary metabolites as sterols, triterpenes, coumarins, flavonoids, alkaloids and anthraquinones that would be to the joint-stock origin conjugated of its noted laxative properties. [ABSTRACT FROM AUTHOR]

Tetrodontium ovatum (Funck) Schwägr. is recorded as new for the French bryoflora, based on a sample collected in the region of Haute-Savoie. Data on its autoecological features are provided. Additionally, its diagnostic characters are discussed and an identification key to Tetrodontium species in France is proposed. [ABSTRACT FROM AUTHOR]

The genus Leptolejeunea (Spruce) Schiffn. was newly discovered for La Reunion Island. The species Leptolejeunea maculata (Mitt.) Schiffn. was sampled living as epiphyllous in the framework of research surveys on the dynamics of bryological vegetation on lowlandlava flows. This species was until now only recorded in Mauritius Island for the Mascarenes archipelago. [ABSTRACT FROM AUTHOR]

Abstract: Palaeobotanical material has been collected from the Callovian of Beni Barka, 4km south of Tataouine (South Tunisia). The fossil plants originate from a limestone formation just below the carbonate bar, that delimits the Beni Oussid member which belongs to the marls and limestones of Tataouine Formation. The floristic composition is marked by the presence of Pteridophytes: Piazopteris branneri (White) Lorch and Coniferophytes: Brachyphyllum trauti Barale et Contini, Pagiophyllum cf. crassifolium Schenk, Araucarites sp., Podozamites sp. This flora was present in a margino-littoral platform situated between the African continent to the south and the South-Tethyan ocean to the north. The autochthony of the locality is demonstrated. Comparisons are made with the floras situated at the northern and southern margins of the Tethys Sea. A sub-tropical climate was present, favouring the development of a ripisilve flora of conifers, with an underwood of ferns. [Copyright &y& Elsevier]

Abstract: The concept of biodiversity hotspot at the regional and global scale has contributed to the improvement of the conservation strategies. The need for precise evaluation is often hampered by lapses of knowledge in some Mediterranean regional hotspots. The objective of the present work is to analyse the diversity of endemic and rare flora in the northern part of Algeria. According to the bibliographical data that are available, the most remarkable areas for endemism are the Oran''s coast, the Great Kabylia, and the Small Kabylia. As far as rare species are concerned, coastal Numidia comes first, then the Algiers surroundings. This group ‘Kabylias–Numidia–Kroumiria’ comprises an unrecognised regional hotspot, made of forests, mountains and coastal ecosystems and threatened by human activities. In the face of growing threats, it is urgent to reinforce national and international policies of conservation and to cooperate for a better floristic knowledge of all the areas mentioned above. To cite this article: E. Véla, S. Benhouhou, C. R. Biologies 330 (2007). [Copyright &y& Elsevier]

Abstract: Archaeological palynology with regards to long pollen records. Pollen analyses from archaeological deposits or from framing prehistoric occupation layers are a contribution to the knowledge of the flora, environment and climate conditions synchronous of occupations of a territory by Hominids. Palynological results are compared with glacial and interglacial episodes from long pollen sequences. Palaeoenvironmental and palaeoclimatic data are interpreted and placed within the Quaternary and Prehistory chronological framework. The Ca’ Belvedere di Monte Poggiolo and La Pineta open-air sites (Italy) and the Vallonnet cave (South-East of France) show evidences for an early colonization of the European Mediterranean basin during the Early Pleistocene. Pollen analyses undertaken in those prehistoric sites have provided new data on the Hominid and their surrounding landscapes. These data are faced with some Early Pleistocene climatic cycles recorded in long and continuous pollen sequences. To cite this article: J. Renault-Miskovsky, V. Lebreton, C. R. Palevol 5 (2006) . [Copyright &y& Elsevier]

Abstract: Pollen analysis of Santa Lucia superiore cave (Italy) reports at local scale the lowland Ligurian vegetation during the Lower Pleniglacial (75 to 57 Kyr BP). The pollen profile shows two AP extensions during a steppe-landscape episode in Liguria. The dry and cold phases caused the establishment of a steppe-landscape (NAP 92%) with Artemisia, Ephedra, Poaceae and Chenopodiaceae, similar to those mentioned in the Latium during the Pleniglacial. The increase of moisture generated a first arboreal extension (Pinus, Betula, Corylus, Ulmus), which engendered the formation of an open-forest landscape (AP 43%). The second arboreal extension (AP 55%) was due to an increase of moisture and higher temperatures, which allowed the development of Mediterranean trees and shrubs (Quercus ilex, Olea, Phillyrea). This warming up occurred probably simultaneously with a secondary transgression during the glacial sea-level change. The upper part of the profile shows an open vegetation, which indicates the return of a steppe-landscape. Pollen data, replaced in the multidisciplinary studies of the site, are well correlated with the fauna and sediment data. [Copyright &y& Elsevier]

Abstract: Palynological analysis of an amber-bearing lignitic clay bed from the Uppermost Albian of Archingeay (Charente-Maritime, France). An amber-bearing lignitic clay bed from Archingeay village (Charente-Maritime, France) yielded a well-preserved, rich and variegated palynoflora, whose origin is mixed between land plants and marine microflora. Its detailed analysis, through light and scanning electron microscopes, led to fulfil its inventory, then to propose a palaeoenvironmental reconstruction and to draw the palaeoclimate which prevailed over the region: an estuarine area under a rather humid, temperate to hot climate. A variety of ferns and resin-producing conifers grew near the shore-side and in the inward land; the angiospermous affinity is worthy of interest, although rather little diversified. Filamentous ‘algae’ grew in the rivers. The marine microflora, moderately diversified, comprises chitinous foraminifer linings, acritarchs and dinoflagellate cysts, among which the Uppermost Albian guide taxa are present; the predominance of neritic species remains somewhat moderate. To cite this article: J. Dejax, E. Masure, C. R. Palevol 4 (2005) . [Copyright &y& Elsevier]

The Late Jurassic – Early Cretaceous series encountered in South-East Tunisia, formely considered globally as Purbecko-Wealdian in age, has the most complete palaeobotanical record of all North-Gondwana. Thanks to the stratigraphical results of the last years and to new field researches, it was possible, for the first time, to evidence an Oxfordian flora at the base of this series (Bir Miteur Formation). This flora, constituted of impressions and axes of Pteridophytes and Gymnosperms, is encountered within different types of plant-bearing levels. The study of deposit facies and sequential analysis of this Oxfordian formation allowed the identification of corresponding sedimentary environments and to infer their palaeoecological meaning. The discovery of exceptional specimens provided new informations about the general morpho-anatomy of Alstaettia, a very peculiar tree fern of a now extinct type. This Oxfordian flora is an interesting key-point in the evolution of North-Gondwanian flora at the Jurassic/Cretaceous transition. [Copyright &y& Elsevier]

Accumulation of Cd in the organs of young tomato plants (Lycopersicon esculentum var. Ibiza F1), as well as its effects on growth, peroxidasic activity, and root ultrastructure were evaluated. Plants previously cultivated in a basic nutrient solution and then treated for 10 days with different concentrations of CdCl[sub 2] (0, 5, 10, 20, 50, 100 µM) accumulated high quantities of cadmium in their root tissues and showed reduced growth. Increased peroxidasic activity observed at this level reflects a state of oxidative stress induced by cadmium. An ultrastructural study of the root apex showed a strong vacuolization in the meristematic cells as well as deposition of electron-dense material in vacuoles and plastids. On either side of the cell wall, a medullated-like and (or) vesicular membrane system developed over a significant periplasmic space. Results suggest an endocellular metal accumulation leading to a disorganization of membrane systems, probably related to the onset of an oxidative state of stress.Key words: cadmium, tomato, peroxidases, ultrastructure, root.[Translated by editorial staff]Ce travail a pour objectif d'évaluer l'accumulation du Cd au niveau des organes de jeunes plants de tomate (Lycopersicon esculentum var. Ibiza F1) ainsi que ses effets sur la croissance, l'activité peroxydasique et l'ultrastructure de la racine. Les plantes préalablement cultivées sur une solution nutritive de base puis traitées pendant 10 jours avec différentes concentrations de CdCl[sub 2] (0, 5, 10, 20, 50, 100 µM) ont montré une forte accumulation du cadmium au niveau des tissus racinaires, accompagnée d'une réduction de la croissance. L'augmentation de l'activité peroxydasique décelée à ce niveau, reflète un état de stress oxydatif induit par le cadmium. L'étude ultrastructurale effectuée dans la région apicale de la racine a mis en évidence une intense vacuolisation au niveau des cellules méristématiques ainsi que des dépôts denses aux électrons dans les vacuoles et les plastes. De part et d'autre de la paroi, un système membranaire d'aspect myélinique et (ou) vésiculaire se développe dans un espace périplasmique important. Ces résultats suggèrent une accumulation endocellulaire du métal, conduisant à une désorganisation des systèmes membranaires probablement en relation avec l'installation d'un état de stress oxydatif.Mots clés : cadmium, tomate, peroxydases, ultrastructure, racine. [ABSTRACT FROM AUTHOR]

In a chalk grassland of the Seine valley in northwestern France, vegetation and seed bank were compared according to their composition, diversity, and spatial structure through use of a spatial sampling design. The results show (i) that it is possible to establish a successional gradient from short grasslands to early stages of forests with vegetation data; (ii) that there is a weak correspondence between vegetation and seed bank (mean similarity 41%), which was mainly dominated by opportunistic annual or biennial species (Hypericum perforatum, Blackstonia perfoliata); (iii) that there are differences between spatial patterns of vegetation and seed bank. These spatial patterns often exhibit a time lag and represent different levels of heterogeneity. The spatial heterogeneity of the seed bank and its independence from the vegetation structure were interpreted according to the functioning of the two compartments and their type of exchanges (through seed rain and seedling recruitment).Key words: chalk grassland, biodiversity, spatial pattern, succession, seed bank, synchronic approach.Dans une pelouse calcicole de la vallée de la Seine au nord-ouest de la France, la végétation et le réservoir de graines du sol ont été comparés selon leur composition, leur diversité et leur structure spatiale, grâce à un plan d'échantillonnage spatialement explicite. Les résultats montrent (i) que l'on peut reconstituer un gradient de succession des stades de pelouses rases aux stades pré-forestiers, à partir des données de la végétation; (ii) qu'il existe une faible correspondance entre la végétation et le réservoir de graines (similarité moyenne de 41 %), dominé essentiellement par des espèces annuelles ou bisannuelles (Hypericum perforatum, Blackstonia perfoliata); (iii) qu'il existe des différences entre les patrons spatiaux de la végétation et du réservoir de graines. Ces patrons spatiaux sont souvent décalés et présentent des niveaux d'hétérogénéité différents. L'hétérogénéité spatiale du réservoir de graines et son indépendance vis-à-vis de la structure de la végétation sont interprétées selon les modes de fonctionnement et les modalités des échanges (pluie de graines, recrutement des semis) entre les deux compartiments.Mots clés : pelouse calcicole, biodiversité, patron spatial, succession, banque de graines, approche synchronique. [ABSTRACT FROM AUTHOR]

Four different plant management treatments, corresponding with different existing growing practices, were compared for flower production of Rosahybrida L. cv. Meiqualis plants grown for 1 year in a greenhouse in the south of France. Two of them used shoot bending during plant formation and subsequent production management. The harvest level practiced on the thickest stems differentiated these two treatments. Two other treatments consisted in using shoot removal and pruning during plant formation. In the first one, during production management, unmarketable shoots were removed by pinching, whereas they were bent and left on the plant in the second one. This last treatment resulted in the highest yield of marketable stems and stem quality after 1 year, although the treatment using shoot bending during plant formation and production associated with a high harvest level on the thickest stems produced the largest quantity during autumn and winter. The results are discussed with reference to different yield components determined by the different plant management treatments applied, such as inter-flush cycle time, bud sprouting, occurrence of certain types of unmarketable stems (blind shoots and bowed peduncled stems), and development of new bottom breaks.Key words: shoot bending, bottom breaks, blind shoots, bowed stems, production, Rosahybrida L.Dans la pratique horticole, il existe de nombreux modes de conduite des plantes applicables au rosier cultivé sous serre, pour la production de fleurs coupées. Ces modes diffèrent selon les traitements appliqués lors des phases de formation des plantes après plantation et de récoltes des tiges. Quatre d'entre-eux ont été comparés pendant 1 an sur des plantes de Rosa hybrida L. cv. Meiqualis cultivées sous serre, dans le sud de la France. Deux des traitements expérimentés incluaient un pliage des rameaux pendant la phase de formation de la plante et durant la conduite de production de fleurs. Le niveau de récolte pratiqué plus ou moins haut sur les tiges les plus grosses différenciait ces deux traitements. Deux autres traitements correspondaient à un ébourgeonnage suivi d'une taille pendant la formation de la plante. Dans le premier, durant la conduite de production, les tiges non commercialisables étaient ôtées par pincement, alors qu'elles étaient pliées et laissées sur la plante dans le second. C'est ce dernier traitement qui a conduit à la plus grande quantité de tiges commercialisables produites et à la meilleure qualité au bout d'un an. Cependant, le traitement qui incluait le pliage de rameaux pendant la formation de la plante et la conduite de production, associé à un niveau élevé de récolte sur les tiges les plus grosses, a conduit aux plus grandes quantités produites durant l'automne et l'hiver. Les résultats sont discutés en relation avec différentes composantes de la production déterminées par les conduites appliquées, telles que la durée des cycles inter-floraisons, le niveau de débourrement des bourgeons, la fréquence d'apparition de certains types de tiges non commercialisables (axes avortés, tiges à pédoncule tordu), l'émission de gourmands.Mots clés : pliage, gourmands, tiges avortées, tiges tordues, production, Rosahybrida L. [ABSTRACT FROM AUTHOR]

Palynological investigation from the Lower Palaeolithic site of La Pineta (Isernia, Molise) reports the environmental and climatic conditions of an old human occupation site in Italy, between the end of the Lower Pleistocene and the beginning of the Middle Pleistocene. The pollen record shows that the end of the Lower Pleistocene was marked by an arid episode. This is related to change in the climatic cycles periodicity from 41 to 100 ka, which occurred between 900 and 800 ka. The post-archaeological layers show new favourable moisture conditions at the beginning of the Middle Pleistocene, when the 100 ka cycles prevail. To cite this article: V. Lebreton, C. R. Palevol 1 (2002) 11–17. [Copyright &y& Elsevier]

This study reveals that morphogenesis of grapevine plants (Vitis vinifera L.) produced in vitro under carbon dioxide enriched atmosphereis largely determined by the morphogenetic pattern of vitroplants on which microcuttings were harvested. The presence of tendrils on shoots or shoot parts from which microcuttings were made was essential to obtain a high percentage of adult vitroplants with ternary sequence of tendrils. Therefore, under in vitro culture conditions, the ability of the axillary meristem to produce tendrils is closely correlated with the ability of the apical meristem from which it originated. The interest of these results is discussed from a fundamental standpoint. It allows to suggest an improved process of adult vitroplants production under high carbon dioxide level in which the relative importance of the selection of microcuttings and the number of subcultures is defined.Key words: maturation, micropropagation, tendrils, Vitis vinifera.Cette étude démontre l'existence d'une corrélation entre la morphogenèse de plants de vigne (Vitis vinifera L.) produits in vitro, sous atmosphère enrichie en gaz carbonique, et les caractéristiques morphogénétiques des vitroplants sur lesquels les microboutures ont été prélevées. La présence de vrilles sur les rameaux ou parties de rameaux à partir desquels les microboutures sont confectionnées est en effet indispensable pour l'obtention d'un pourcentage élevé de vitroplants adultes avec la séquence ternaire de production des vrilles. Les capacités d'un méristème axillaire d'un vitroplant à édifier des vrilles sont donc corrélées avec celles du méristème terminal qui lui a donné naissance. Outre leur intérêt fondamental qui est discuté, ces résultats permettent de proposer une amélioration du procédé de production des vitroplants adultes, sous atmosphère enrichie en gaz carbonique, dans laquelle l'importance relative de la sélection des microboutures et du nombre de subcultures est précisément définie.Mots clés : maturité, micropropagation, Vitis vinifera, vrilles. [ABSTRACT FROM AUTHOR]

Nitrate exsorption in relation to light was studied in four wheat (Triticum aestivum L.) cultivars, Sais, Jouda, Marchouch, and Khair, using four experimental treatments: intact plants, excised roots, defoliated plants, and decapitated plants. Data show that nitrate exsorption was dramatically reduced from excised roots compared to controls. This efflux reduction was also observed from the roots of decapitated plants. On the contrary, defoliation triggered a significant increase in the quantity of exsorbed NO[sub 3] [sup –] , as compared to intact plants. This increased efflux was much more dramatic when defoliated plants were exposed to darkness; nitrate exsorption from roots was then 8 to 10 times larger than from excised roots. In 21-day-old wheat plantlets, the aboveground parts are the main site for efflux regulation at the root level. Both leaves and apex are the aboveground organs responsible for this regulation. Indeed, the efflux was reduced by the leaves and, on the contrary, stimulated by the apex. Light was involved in controlling this efflux. This control involves a flow, between the aboveground parts and the roots, of two types of factors, one of which (or both) being sensitive to light. The first factor is of apical origin, whereas the second is of foliar origin. However, the chemical nature of these two types of photosensitive factors involved in NO[sub 3] [sup –] ions efflux regulation remains to be determined.Key words: nitrate, efflux, light, darkness, common wheat.[Journal translation]L'exsorption des nitrates en relation avec la lumière a été étudiée chez quatre cultivars de blé tendre (Triticum aestivum L.), Sais, Jouda, Marchouch et Khair, dans quatre conditions expérimentales : plantes intactes, racines excisées, plantes défoliées et plantes décapitées. Les résultats obtenus montrent que l'exsorption des nitrates est fortement diminuée chez les racines excisées comparativement aux plantes témoins. Cette diminution est aussi observée chez les plantes décapitées. La défoliation provoque, au contraire, une augmentation significative de la quantité de NO[sub 3] [sup –] exsorbé par rapport aux plantes intactes. Cette augmentation de l'efflux est beaucoup plus spectaculaire lorsque les plantes défoliées sont exposées à l'obscurité; les racines exsorbent alors 8 à 10 fois plus de nitrates que les racines excisées. Chez les plantules de blé âgées de 21 jours, la partie aérienne est le site principal de régulation de l'efflux au niveau des racines. Les feuilles et l'apex constituent conjointement les organes de la partie aérienne responsables de cette régulation. En effet, l'efflux est freiné par les feuilles et stimulé, au contraire, par l'apex. La lumière est impliquée dans le contrôle de cet efflux. Ce contrôle met en jeu un trafic, entre la partie aérienne et les racines, de deux types de facteurs dont l'un et (ou) l'autre sont sensibles à la lumière. Le premier facteur est d'origine apicale, alors que le second est d'origine foliaire. Il reste toutefois à déterminer la nature chimique de ces deux types de facteurs photosensibles impliqués dans le processus de contrôle de l'efflux des ions NO[sub 3] [sup –] dans le milieu.Mots clés : nitrate, efflux, lumière, obscurité, blé tendre. [ABSTRACT FROM AUTHOR]

Organic and mineral components have been analysed on 18 dicotyledonous species of permanent grassland communities. Multivariate analysis revealed an opposition between a macromolecular pool (cellulose and lignin) and a nutrient pool (potassium and phosphorus, nitrogen). The first pole is characterized by Tragopogon pratensis L. (Compositae) and Galium mollugo L. (Rubiaceae), the second by Anthriscus sylvestris (L.) Hoffm. (Umbelliferae) and Geranium sylvaticum L. (Geraniaceae). The most thermo-helio-xerophilous species (Knautia arvensis (L.) Coult and Tragopogon pratensis) belong to the first group, whereas the second group includes the cool-environment species (like Alchemilla xanthochlora Roth.), which reveals an ecophysiological determinism. Moreover, correlations between the biochemical and ecological structure, and other interrelated parameters, including sclerophylly, have been shown. Compared to lignous and sempervirent plant communities, the grassland species have lower phenolic and lignin contents but higher glucide and nutrient (potassium and phosphorus) contents, which is in accordance with their food value. For this herbaceous community, the C/N ratio indicates the same general equilibrium between cell-wall macromolecules and nitrogen than for two other plant communities (mainly ligneous) previously studied, with some differences revealing distinct trends from the same general metabolic sheme.Key words: dicotyledonous plant communities, biochemical organization, C/N ratio, ecophysiology.Les constituants organiques et minéraux de 18 dicotylédones de prairies permanentes ont été analysés. Après analyse multivariable, une bipolarisation apparaît entre un pool macromoléculaire (cellulose et lignine) et un pool d'éléments biogènes (potassium et phosphore, azote). Comme espèces caractéristiques, on peut citer, dans le premier cas, le Tragopogon pratensis L. (Composées) et le Galium mollugo L. (Rubiacées), et dans le second cas, l'Anthriscus sylvestris (L.) Hoffm. (Ombellifères) et le Geranium sylvaticum L. (Géraniacées). Au premier pôle correspondent les espèces les plus hélioxérothermophiles (Knautia arvensis (L. Coult) et Tragopogon pratensis), au second les espèces de milieux frais (comme l'Alchemilla xanthochlora Roth.), traduisant ainsi l'existence d'un déterminisme écophysiologique. En outre, des corrélations apparaissent entre cette organisation biochimique et écologique, et d'autres paramètres eux-mêmes liés, comme la sclérophyllie. Comparées à d'autres communautés végétales, ligneuses et sempervirentes, les formations prairiales sont déficitaires en composés phénoliques et en lignine, plus riches par contre en glucides et en éléments biogènes (potassium et phosphore), ce qui justifie leur valeur alimentaire. Pour cette communauté herbacée, le rapport C/N illustre le même équilibre général entre macromolécules pariétales et azote que pour deux autres communautés végétales (à dominante ligneuse) précédemmment étudiées, les différences observées traduisant des orientations distinctes à partir d'un schéma métabolique commun.Mots clés : communautés végétales dicotylédones, organisation biochimique, rapport C/N, écophysiologie. [ABSTRACT FROM AUTHOR]

Litter falls and their contributions to soil nutriments were measured in five distinct facies of a mangrove in French Guyana. These facies were characterized by their distance from the sea, their floral composition (Laguncularia racemosa (L.), Avicennia germinans (L.) Stearn, Rhizophora spp.), and their structural features. Data were analyzed according to facies and to species for litters, as well as to seasons for the nutriments. This mangrove produced respectively 8.8 and 8.7 t·ha[sup –1] ·year[sup –1] of litter at the pioneer and senescent stages submitted to strong environmental constraint and 12.5 and 12.6 t·ha[sup –1] ·year[sup –1] for young and mature stages where developmental conditions are optimum. Nitrogen and carbon inputs were estimated to 1.3 × 10[sup –2] and 6.4 t·ha[sup –1] ·year[sup –1] , respectively. Litter appeared rich in phosphorous, corresponding with the high concentrations characterizing the sediments. For a given species, magnesium and calcium concentrations were constant between facies, whereas potassium and sodium concentrations varied according to the distance from the sea. Differences were perceived between species for all nutriments except sodium. Results are discussed in relation with the ecophysiological characteristics of the mangrove trees and the specific sedimentology of Guyana coast and are replaced in the perspective of an improved knowledge of the carbon and mineral balances in tropical coastal ecosystems.Key words: mangrove, French Guyana, litter, carbon balance, mineral nutriments, spatial variations.[Journal translation]Les auteurs ont mesuré les chutes de litière et les apports au sol en nutriments d'une mangrove de Guyane française dans laquelle cinq faciès sont distingués selon leur distance à la mer, leur composition floristique (Laguncularia racemosa (L.) Gaertner f., Avicennia germinans (L.) Stearn, Rhizophora spp.) et leurs caractéristiques structurales. Les résultats sont analysés en fonction des faciès et des espèces pour les litières, ainsi que des saisons pour les nutriments. La mangrove produit respectivement 8,8 et 8,7 t ha[sup –1] a[sup –1] de litière pour les stades pionnier et sénescent soumis à des contraintes écologiques fortes, et 12,5 et 12,6 t ha[sup –1] a[sup –1] pour les stades jeune et adulte où les conditions de développement sont optimales. Les apports en azote et carbone sont évalués respectivement à 1,3 × 10[sup –2] et 6,4 t ha[sup –1] a[sup –1] . La litière s'avère riche en phosphore, ce qui est en accord avec les fortes teneurs en cet élément caractérisant les sédiments. Pour une espèce donnée, les concentrations de magnésium et de calcium sont stables d'un faciès à l'autre, alors que celles du potassium et du sodium varient selon l'influence maritime. Des différences apparaissent entre espèces pour tous les éléments à l'exception du sodium. Les résultats sont discutés en fonction des caractéristiques écophysiologiques des palétuviers et des particularités sédimentologiques de la côte guyanaise et sont replacés dans la perspective d'une meilleure connaissance des bilans carbonés et minéraux des écosystèmes côtiers tropicaux.Mots clés : mangrove, Guyane française, litière, bilan carboné, éléments minéraux, variations spatiales. [ABSTRACT FROM AUTHOR]

Seeds of tomato (Lycopersicum esculentum L. cv. Gribovsky‐1180) and carrot (Daucus carota L. cv. Santanet) were irradiated by continuous light of different wavelengths (white, blue, green, red, far‐red and He‐Ne laser) and different power density. Free radical output was measured using Electron Spin Resonance spectra (ESR). The dependence of the content of free radicals (FR) on the light power density was established. The yield of FR in the seeds irradiated with monochromatic light of the same power density was inversely proportional to the wavelength. The ESR spectra showed maximum absolute number of FR for white light. Successive irradiations gave cumulative effects on the output of free radicals in both directions: increase by the action of white light and decrease by the action of red and far‐red light. The contact of irradiated seeds with steam decreased the amount of FR. [ABSTRACT FROM AUTHOR]

Local cooling (1.5°C) of the stem (on 2 or 4 cm) a Vicia faba L. cv. Aguadulce for 15 h stops the exogenous IAA transport from the apical bud and causes a high accumulation of tracers above and at the level of the cooled zone. This clamping effect is reversed after removal of the cooling system. If the cooling system is maintained for 48 h, about 25% of the exported radioactivity passes the cooled zone. However, the percentage IAA transmitted decreases to about 6.6% if the cooled zone is sufficiently wide (4 cm) and the temperature lowered to 0.7°C±0.3°C. Using a cooling system of 4 cm (0.7±0.3°C) partially releases the lowermost axillary buds (ax1 and ax2) from apical dominance. Yet, the rate of growth of the axillary buds is generally lower than the growth rate after decapitation of the plant. [ABSTRACT FROM AUTHOR]

The study of the sensitiveness of 16 varieties or lines of Triticinae against two races of Pseudocercosporella herpotrichoides shows that, whatever the strain used, the importance of the attacks is much less serious on seedlings of Ae. ventricosa no. 11, Ae. squarrosa no. 15, Ae. squarrosa no. 33 and Roazon. Roazon was the least sensitive among the Triticum. It is obvious that Ae. ventricosa is the most resistant one in all varieties or lines used. [ABSTRACT FROM AUTHOR]

Pedunculate oak seedlinbgs were inoculated in the nursery with three ectomycorrhizal fungi. Results are discussed in connexion with the type of inoculom and the interactions between microbial populations in the substrate. [ABSTRACT FROM AUTHOR]

This article discusses the epidemiology of Marssonina brunnea , a leaf parasite of cultivated poplars. The relationship between outbreaks of the disease and ripening of ascospores, and the release of conidia in spring was studied in the year 1972 and 1973 in the north and the east of France. Climatic conditions play an important role in the occurrence of primary infection. During the growing season, spores are released after each rainfall, but the number of spores trapped varies considerably. It is very high after heavy rainfall.

Ectendomycorrhizae of Pinus mugo + Boletusedulis ssp. edulis and Pinus cembra + Suillus variegatus formed in pure culture, These associations have not been suspected hitherto in nature because sporocarps do not occurs [ABSTRACT FROM AUTHOR]

Ectendomycorrhizae obtained by growing Pinus sylvestris and Rhizopogon rubescens in vitro were compared with ectomycorrhizae of the same association produced in vivo as described by FONTANA et al. (1967). [ABSTRACT FROM AUTHOR]

The fungus forms an extremely thick mantle and a strongly developed Hartig net. [ABSTRACT FROM AUTHOR]