Sylvie Sabatier

Cirad - La recherche agronomique pour le développement | CIRAD · Joint research unit AMAP «Botany and Computational Plant Architecture »

The architectural plasticity forms observed in trees is a result of meristem functioning, which generates new organs and branches, and adjusts growth processes in response to heterogeneous climatic adaptations that affect biomass allocation. Analyzing this plasticity should enable the selection of adapted individuals for optimizing successful cropp...

La déforestation menace fortement l’environnement et la biodiversité dans le monde et particulièrement en Côte d’Ivoire. Il paraît nécessaire de développer des stratégies de restauration, de conservation et de gestion durable d’espèces pionnières issues des écosystèmes dégradés. L’étude vise à optimiser la culture de trois espèces forestières in...

The wild species of the Coffea genus present a very wide morphological, genetic, and biochemical diversity. Wild species are recognized more resistant to diseases, pests, and environmental variations than the two species currently cultivated worldwide: C. arabica (Arabica) and C. canephora (Robusta). Consequently, wild species are now considered as...

Les formes plastiques d'architecture observées chez les arbres résultent du fonctionnement des méristèmes, qui produisent de nouveaux organes et branches, et de l'ajustement des processus de croissance en réponse à des adaptations climatiques hétérogènes affectant l'allocation de la biomasse. L'analyse de cette plasticité devrait permettre de sélec...

Seed size is a critical factor that can impact the regeneration process of plant populations. The objective of this study is to identify optimal seeds for the cultivation of two overexploited native forest species in Côte d’Ivoire, namely Khaya senegalensis (Desr.) A.Juss., 1830 and Parkia biglobosa (Jacq.) R.BR. ex G. Don, 1830. A total of 1080 se...

Seed size is a key factor that can affect the regeneration process of plant populations. This study aims to identify efficient seeds that can optimise the cultivation of two overexploited native forest species in Côte d'Ivoire, namely Khaya senegalensis and Parkia bliglobosa . Sets of 1080 seeds per species were tested for their germination and see...

The group of Baracoffea includes 9 endemic deciduous species which are exclusively present in the dry forests of the West coast of Madagascar. They are particularly well adapted to xerophytic conditions. Deforestation and anthropic activities have caused a strong fragmentation of the Malagasy forests and considerably modified the natural forest eco...

La modélisation de la croissance et de l’architecture des plantes (modélisation structure-fonction des plantes ou FSPM) s’inscrit logiquement dans le cadre d’une discipline récente, dénommée « biologie intégrative ». Selon Gilbert Chauvet (1993) : « La biologie intégrative est une nouvelle science, dont le développement pose des difficultés théoriq...

Pterocarpus erinaceus est une espèce largement utilisée par les populations des zones sahéliennes et soudaniennes. Cependant, cette espèce est menacée par l’exploitation abusive des peuplements naturels. La présente étude vise à déterminer un idéotype de profondeur de semis des graines de Pterocarpus erinaceus pour relever le taux de germination de...

Seed size is a key factor that can affect the regeneration process of plant populations. This study aims to identify efficient seeds that can optimise the cultivation of three overexploited native forest species in Côte d'Ivoire, namely Khaya senegalensis, Pterocarpus erinaceus and Parkia bliglobosa. A germination potential and vigorous seedling te...

Les avancées technologiques de l’utilisation du bois et des plantes à haute valeur ajoutée dans la préservation de l’environnement. Les forêts occupent une place importante dans les écosystèmes mondiaux. Selon la FAO, les forêts représentaient 30% de la superficie terrestre en 2005 et 80% de cette superficie forestière sont situés dans les pays du...

Parkia biglobosa is a much-loved and over-exploited African savannah spe- cies for its socio-economic importance. Knowing and taking into account its architectural unit, which is the basis for diagnosing phenology, productivity and tree health, could provide a new perspective on its sustainable manage- ment. The aim of this study is to establish...

Architecture and structure-function modelling of native agroforestry species of Côte d'Ivoire

Key message The determination by non-destructive measurement of biomass and leaf area is of great interest to avoid any plant degradation. These data are necessary for biomass allocation and estimation of carbon distribution in trees using functional and structural growth models such as GREENLAB. Abstract Organ biomass and leaf area are important...

In Côte d'Ivoire, biodiversity is threatened by deforestation, which has spread to the savannah areas. Reforestation and agroforestry based on local species are the two solutions chosen by Côte d'Ivoire to cushion and mitigate the negative consequences of this phenomenon. Khaya senegalensis, Pterocarpus erinaceus and Parkia biglobosa are three indi...

Seed size and the growth environment are important variables that influence seed germination, growth and biomass of seedlings and future tree harvest and should thus be taken into account in agroforestry and reforestation programmes for endangered species like Pterocarpus erinaceus. In the present study, to assess seedling germination and vigour in...

Seed size and the growth environment are important variables that influence seed germination, growth and biomass of seedlings and future tree harvest and should thus be taken into account in agroforestry and reforestation programmes for endangered species like Pterocarpus erinaceus. In the present study, to assess seedling germination and vigour in...

Néré (Parkia biglobosa) is a wild species preferred and overexploited for its multiple uses by rural populations in Sub-Saharan Africa. The study of its germination and seedlings could constitute a prerequisite for its domestication, necessary for its conservation. This study aimed to assess the germination and morphology of seedlings taking int...

Passage à l’agriculture ou dégradation de la forêt, comprendre la notion de « zéro déforestation ». Pour supprimer la déforestation importée à l’horizon 2030, quels sont les instruments d’action publique efficaces ?

Currently, the whole world is facing the problem of global warming, the main cause of which is anthropogenic activity. In Madagascar, deforestation and other anthropogenic activities have caused severe forest fragmentation and have significantly altered natural forest ecosystems. One of the direct consequences is that nearly 75% of Malagasy coffee...

Interpretation of primary growth markers (modules) is neglected in sustainable resource management processes, yet it opens up prospects for long time series on tree crown development, necessary for their characterization in the current context of climate change. This study aimed to assess the morphological variation of crown shoots in Parkia biglob...

Pterocarpus erinaceus is over-exploited for its multiple uses. Its exploitation and trade are strictly prohibited in many countries, including Côte d'Ivoire, to prevent its extinction. It is nevertheless imperative to restore populations of this species, while accounting for its germinative capacities and its adaptation to changing climates. The ai...

Coffee is a beverage enjoyed by millions of people worldwide and an important commodity for millions of people. Beside the two cultivated species (Coffea arabica and Coffea canephora), the 139 wild coffee species/taxa belonging to the Coffea genus are largely unknown to coffee scientists and breeders although these species may be crucial for future...

Background and aims: Using internal trophic pressure as a regulating variable to model the complex interaction loops between organogenesis, production of assimilates and partitioning in functional-structural models of plant growth has attracted increasing interest in recent years. However, this approach is hampered by the fact that internal trophi...

One factor that determines a tree’s resilience capacity to drought is its level of interaction with aggravating biotic factors, such as bark beetles, which in turn depends on whether insect populations are at an endemic or epidemic stage. In a Mediterranean natural forest ecosystem, we investigated the ecophysiological characteristics of trees whic...

Background and aims: Like other clades, the Coffea genus is highly diversified on the island of Madagascar. The 66 endemic species have colonized various environments and consequently exhibit a wide diversity of morphological, functional, phenological features and reproductive strategies. The trends of interspecific trait variation, which stems fr...

Understanding the processes driving plant phenology is crucial for assessing how shifts in climate affect plant productivity and species’ distribution. Despite the key role of fine roots in carbon and nutrient cycling, root phenology is less well characterized than shoot phenology, due largely to methodological problems when measuring root systems...

Dans le contexte actuel d'accélération du changement climatique, l'étude des mécanismes d'adaptation à la sécheresse est primordiale pour la conservation des espèces et en particulier pour l'amélioration des espèces cultivées de caféiers. A ce stade, Baracoffea émergent un intérêt botanique et économique, regroupant les caféiers sauvages xérophytiq...

The rapid rate of deforestation in Côte d’Ivoire has led to loss of plant species diversity and also threatens some commercial tree species with extinction. Some reforestation and afforestation has been completed. However, for some species, the numbers of surviving transplants has declined. Hence, it is necessary to develop properly adapted and res...

Water and potassium are limiting factors for tree growth. Their influence on morphology and anatomy are well known, but their combined effects on tree growth remain to be clarified. A single clone of Eucalyptus grandis was analyzed under different treatments of rainfall exclusion and fertilization. Eight trees per treatment were sampled to investig...

The complex interaction loops between organogenesis, assimilate production and partitioning are a crucial core component of most functional-structural plant growth model; yet these three processes are seldom fully coupled and there is no consensus on how it should be done. In this context, the use of the internal trophic pressure as a regulating va...

Knowledge of plant architecture allows retrospective study of plant development, hence provides powerful tools, through modelling and simulation, to link this development with environmental constraints, and then predict its response to global change. The present study aims to determine some of the main endogenous and exogenous variables driving the...

The coffee tree is an important economic plant for several developing countries. Stem and leaf dry biomass, which are key traits of plant production, are used in functional-structural plant models to simulate plant growth and predict yield. These values are difficult to obtain since they classically rely on time-consuming protocols and require dest...

Background and aims: For a given genotype, the observed variability of tree forms results from the stochasticity of meristem functioning and from changing and heterogeneous environmental factors affecting biomass formation and allocation. In response to climate change, trees adapt their architecture by adjusting growth processes such as pre- and n...

Background and aims Plant phenology is a sensitive indicator of plant response to climate change. Observations of phenological events belowground for most ecosystems are difficult to obtain and very little is known about the relationship between tree shoot and root phenology. We examined the influence of environmental factors on fine root productio...

The number of organs produced by a plant varies among the individuals of a population. Taking these variations into account is an important step in understanding phenotypic variability. The aim of this study was to simulate stochastic development and growth in response to environmental change using GreenLab, an organ level functional-structural mod...

Key message: The chronology of periods of organogenesis and elongation is highlighted in Pinus halepensis. The two first growth units of an annual shoot are preformed inside the bud during the previous year. The following growth units are formed during the spring or summer of the current year. Context: Analysis of annual shoot length growth phenolo...

Key message: The chronology of periods of organogenesis and elongation is highlighted in Pinus halepensis. The two first growth units of an annual shoot are preformed inside the bud during the previous year. The following growth units are formed during the spring or summer of the current year. Context: Analysis of annual shoot length growth phenolo...

FSPM Plant and crop models are popular in the research community and there is increasing interest in their applications, from yield prediction to crop management optimization. A wide range of approaches and their software implementation can be found in the literature, with a large diversity in modelling scale (from plant organ to plot levels) and s...

Key messageA retrospective architectural analysis performed on planted teaks in Togo showed that the variation of wood radial properties were linked with tree ontogeny, and that these relationships depended on thinning practices and provenance.ContextVariability in growth, flowering and forking in individual trees according to origin and/or thinnin...

Plant architecture can be used to study plant development retrospectively thanks to time-dépendent morphological markers, particularly those corresponding to the winter break in temperate regions. The Aleppo Pine and the Turkish Pine are polycyclic species, thus they usually develop several consecutive growth units per year, making it sometimes dif...

Key message The surface area and dry biomass of leaves can be satisfactorily estimated from simple dimension measurements. These data are useful for estimating carbon allocation in trees using functional-structural growth models. Abstract Leaf area and leaf dry biomass are key parameters linked to plant production and they are used in functional-st...

This study aimed to identify robust indicators that summarize the respective importance of ontogeny and environmental constraints in tree development. In the proposed approach, tree growth data correspond to the retrospective measurement of annual shoot characteristics (e.g. length, number of branches) along the main stem. We applied segmentation m...

Basés sur le diagnostic architectural, quatre outils sont proposés pour diagnostiquer les arbres et évaluer leur réactivité face aux perturbations environnementales. Le diagnostic ontogénique, outil déjà utilisé, permet d'identifier le stade de développement de l'arbre. Des checklists de marqueurs architecturaux listent les critères pour décrire un...

The genetic diversity of endemic Madagascan Coffea species has not received any considerable attention, despite the high extinction threat facing most of the species on the island. In order to address this shortfall, we assessed and compared the genetic diversity and allelic richness of ex situ and in situ populations for four selected species, and...

Climate change and extreme events have a deep and long lasting impact on tree architectural development, through a limitation of branching rate, leaf or needle size and number, and changes in reproduction patterns. These limitation

This paper demonstrate that tree architectural development of is highly dependent on climate variations and accidents, particularly at the level of their branch ramification rate and polycyclism. Similarly, the number, size and life span of leaves on a twig vary annually with the climate. By means of a growth simulator, we show that the deficit of...

Understanding the mechanisms of plant adaptation to their habitat can help developing relevant conservation politics, which is a crucial issue for several Coffea species. This comes through an understanding of the links between genetic diversity and architectural plasticity. In this study, we investigated the biomass production and allocation strat...

Context Understanding the effects of exogenous factors on tree development is of major importance in the current context of global change. Assessing the structure development of trees is difficult given that they are large and complex organisms with lifespan of several decades. Aims We used a retrospective analysis to derive the ontogenetic trends...

Developmental plasticity, the acclimation of plants to their local environment, is known to be crucial for the fitness of perennial organisms such as trees. However, deciphering the many possible developmental and environmental influences involved in such plasticity in natural conditions requires dedicated statistical models integrating development...

Extension growth, number of internodes of the main stem, and sylleptic branches were recorded weekly during the 1994 growing season on 1-year-old Juglans regia L. cv. Lara scions. Date of sylleptic branch production and branch position on the main stem were also recorded. Two main stem types were distinguished according to their growth pattern: con...

In agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently, on the architecture of the tree species present. The influence of tree architecture on ligh...

Endogenous variations in the annual growth of trees suggest that similar trends would occur in phyllodes. In comparison to leaves, the characteristics of phyllodes are less well known, hence this study examines the effects of architectural position and age of tree on the phyllodes of Acacia mangium. Phyllodes were investigated on 1-, 2-, and 3-year...

A model for the vertical location of whorl and interwhorl branches was constructed for Atlas cedar (Cedrus atlantica Manetti). The vertical location of branches in the crown partly governs their further growth and mortality from which depend (i) the stem growth and form and (ii) the quality of lumber and veneer, including wood knots. The modeling m...

Neoformation is the process by which organs not preformed in a bud are developed on a growing shoot, generally after preformation extension. The study of neoformation in trees has been hindered due to methodological reasons. The present report is aimed at assessing the relative importance of preformation and neoformation in the development of shoot...

ARCHIMED software has been used to estimate the radiative environment of plant stands constituted by 3D virtual plants. The 3D virtual trees used for computation of radiative characteristics were built using the plant generator AMAPsim. Modelling of the functioning of meristems is based upon stochastic processes. The architecture of plants was desc...