Morphologie végétale

Phytomorphology is the study of the physical form and external structure of plants. This is usually considered distinct from plant anatomy, which is the study of the internal structure of plants, especially at the microscopic level. Plant morphology is useful in the visual identification of plants. Recent studies in molecular biology started to investigate the molecular processes involved in determining the conservation and diversification of plant morphologies. In these studies transcriptome conservation patterns were found to mark crucial ontogenetic transitions during the plant life cycle which may result in evolutionary constraints limiting diversification. Plant morphology "represents a study of the development, form, and structure of plants, and, by implication, an attempt to interpret these on the basis of similarity of plan and origin". There are four major areas of investigation in plant morphology, and each overlaps with another field of the biological sciences. First of all, morphology is comparative, meaning that the morphologist examines structures in many different plants of the same or different species, then draws comparisons and formulates ideas about similarities. When structures in different species are believed to exist and develop as a result of common, inherited genetic pathways, those structures are termed homologous. For example, the leaves of pine, oak, and cabbage all look very different, but share certain basic structures and arrangement of parts. The homology of leaves is an easy conclusion to make. The plant morphologist goes further, and discovers that the spines of cactus also share the same basic structure and development as leaves in other plants, and therefore cactus spines are homologous to leaves as well. This aspect of plant morphology overlaps with the study of plant evolution and paleobotany. Secondly, plant morphology observes both the vegetative (somatic) structures of plants, as well as the reproductive structures.

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https://fr.wikipedia.org/wiki/Morphologie_végétale

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Catégories associées (203)

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Publications associées (24)

MSE-466: Wood structures, properties and uses

The presentation of tree growth and formation of wood anatomical structures, linked to the description of specific physical and mechanical properties, makes it possible to understand the different for

Glaïeul

Les Glaïeuls (Gladiolus) sont un genre de plantes de la famille des Iridacées qui compte plus de 260 espèces. Ce sont des plantes vivaces à cormes qui sont maintenant largement utilisées comme plantes ornementales en massifs ou pour la production de fleurs coupées. Le nom glaïeul dérive du latin gladius, signifiant « glaive ». Gladiolus, qui signifie « petit glaive » en latin, fait référence à la forme des feuilles. Ces dernières sont surmontées par une inflorescence en épi. Suivant les espèces, la taille de la plante est variable.

Fruit (botanique)

thumb|Différents fruits. Le fruit, en botanique, est l'organe végétal contenant une ou plusieurs graines. Caractéristique des Angiospermes, il succède à la fleur par transformation du pistil. La paroi de l'ovaire forme le péricarpe du fruit et l'ovule donne la graine. Ce qui est appelé « fruit » dans le langage alimentaire courant peut être biologiquement parlant un fruit ou un faux-fruit (pomme, ananas...). À l'inverse, un fruit biologique (ou un faux-fruit) peut être désigné couramment comme « légume » (avocat, tomate.

Histoire évolutive des végétaux

vignette|Arbre phylogénétique des plantes terrestres indiquant la taille du génome dans les principales familles. vignette|Arbre de parenté des végétaux. L’histoire évolutive des végétaux est un processus de complexification croissante, depuis les premières algues, en passant par les bryophytes, les lycopodes et les fougères, jusqu'aux complexes gymnospermes et angiospermes actuels. Bien que les végétaux plus primitifs continuent de prospérer, particulièrement dans leur milieu d'origine, chaque nouveau degré d'organisation évolue et développe de nouvelles capacités qui lui permettent de mieux s'adapter à de nouveaux milieux.

Recherche écologique: Madagascar en Colombie

Explore le voyage d'un écologiste de Madagascar à la Colombie, couvrant les tourbières, la restauration des sols et les plantations de palmiers à huile.

Espèces de bois : Picea Abies MSE-466: Wood structures, properties and uses

Explore les caractéristiques botaniques, la distribution et les utilisations de Picea Abies, communément connu sous le nom d'épinette de Norvège.

Anatomie du bois: Structures et fonctions des cellules MSE-466: Wood structures, properties and uses

Explore l'anatomie du bois, en se concentrant sur les structures cellulaires et les fonctions comme les nœuds et les anneaux annuels.

Genetic variation and evolutionary history of a mycorrhizal fungus regulate the currency of exchange in symbiosis with the food security crop cassava

Romain Savary, Cindy Dupuis

Most land plants form symbioses with arbuscular mycorrhizal fungi (AMF). Diversity of AMF increases plant community productivity and plant diversity. For decades, it was known that plants trade carbohydrates for phosphate with their fungal symbionts. However, recent studies show that plant-derived lipids probably represent the most essential currency of exchange. Understanding the regulation of plant genes involved in the currency of exchange is crucial to understanding stability of this mutualism. Plants encounter many different AMF genotypes that vary greatly in the benefit they confer to plants. Yet the role that fungal genetic variation plays in the regulation of this currency has not received much attention. We used a high-resolution phylogeny of one AMF species (Rhizophagus irregularis) to show that fungal genetic variation drives the regulation of the plant fatty acid pathway in cassava (Manihot esculenta); a pathway regulating one of the essential currencies of trade in the symbiosis. The regulation of this pathway was explained by clearly defined patterns of fungal genome-wide variation representing the precise fungal evolutionary history. This represents the first demonstrated link between the genetics of AMF and reprogramming of an essential plant pathway regulating the currency of exchange in the symbiosis. The transcription factor RAM1 was also revealed as the dominant gene in the fatty acid plant gene co-expression network. Our study highlights the crucial role of variation in fungal genomes in the trade of resources in this important symbiosis and also opens the door to discovering characteristics of AMF genomes responsible for interactions between AMF and cassava that will lead to optimal cassava growth.

2020

Disentangling the impacts of rising temperature and evaporative demand on plants water status

Laura Mekarni

This study focuses on two of the impacts of global warming (increasing temperatures and increasing vapor pressure deficit - VPD) on plants water status. Three different tree species were selected and young three-years-old trees were placed in conditioned chambers. A total of 6 chambers each accommodated 6 plants of each species. This report presents the results of two measurement sessions: a first session (at time t0) before which all the chambers were configured under the same so-called "normal" conditions, then a second session, after 45 days during which each chamber represented a different combination of temperature and VPD. The experimental set-up therefore allowed to decorrelate these two environmental variables which in nature are always positively correlated, making it difficult to understand the specific impacts of each one. A workflow for in-vivo microCT living trees scanning has been defined and improved during this study, and the resulting images allowed to assess correctly the embolism inside the living trees. It has been shown that the three species had a different sensitivity to temperature and VPD increase, and statistical analyses showed a significant effect of temperature and VPD respectively, as well as a significant interaction between those two climatic parameters in certain cases.

2020

Edge influence on understorey plant communities depends on forest management

Matteo Tolosano

Questions Does the influence of forest edges on plant species richness and composition depend on forest management? Do forest specialists and generalists show contrasting patterns? Location Mesic, deciduous forests across Europe. Methods Vegetation surveys were performed in forests with three management types (unthinned, thinned 5-10 years ago and recently thinned) along a macroclimatic gradient from Italy to Norway. In each of 45 forests, we established five vegetation plots along a south-facing edge-to-interior gradient (n = 225). Forest specialist, generalist and total species richness, as well as evenness and proportion of specialists, were tested as a function of the management type and distance to the edge while accounting for several environmental variables (e.g. landscape composition and soil characteristics). Magnitude and distance of edge influence were estimated for species richness per management type. Results Greatest total species richness was found in thinned forests. Edge influence on generalist plant species richness was contingent on the management type, with the smallest decrease in species richness from the edge-to-interior in unthinned forests. In addition, generalist richness increased with the proportion of forests in the surrounding landscape and decreased in forests dominated by tree species that cast more shade. Forest specialist species richness, however, was not affected by management type or distance to the edge, and only increased with pH and increasing proportion of forests in the landscape. Conclusions Forest thinning affects the plant community composition along edge-to-interior transects of European forests, with richness of forest specialists and generalists responding differently. Therefore, future studies should take the forest management into account when interpreting edge-to-interior because both modify the microclimate, soil processes and deposition of polluting aerosols. This interaction is key to predict the effects of global change on forest plants in landscapes characterized by the mosaic of forest patches and agricultural land that is typical for Europe.

WILEY2020

Culture sélective des plantes

La culture sélective des plantes, ou sélection végétale ou amélioration des plantes, est le processus par lequel l'être humain modifie une espèce végétale. Cette sélection peut avoir différents buts, dont l'adaptation à un usage agricole ou l'élaboration de variétés décoratives pour l'horticulture. Les critères visés sont divers et dépendent de l'utilisation finale de l'espèce ciblée; du point de vue agronomique il s'agit généralement d'améliorer la productivité, de modifier le goût, les qualités nutritionnelles, l'apparence ou encore la résistance aux maladies et aux insectes ravageurs.

Physiologie végétale

thumb|Un laboratoire de phytobiologie en 1901. La physiologie végétale, ou phytobiologie, est la science qui étudie le fonctionnement des organes et des tissus végétaux. Elle cherche à préciser la nature des mécanismes grâce auxquels les organes remplissent leurs fonctions.

Organisme (physiologie)

thumb|Les bactéries Escherichia coli sont des organismes unicellulaires. Un organisme (du grec organon, « instrument »), ou organisme vivant, est, en biologie et en écologie, un système vivant complexe, organisé et est le produit de variations successives au cours de l'évolution. Il est constitué d'une ou plusieurs cellules vivantes (on parle alors, respectivement, d'organisme unicellulaire ou pluricellulaire). Les organismes vivants sont classifiés en espèces partageant des caractéristiques génétiques, biologiques et morphologiques communes.