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Michael Dingkuhn - One of the best experts on this subject based on the ideXlab platform.
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simulation of inflorescence dynamics in oil palm and estimation of environment sensitive phenological phases a model based analysis
Functional Plant Biology, 2013Co-Authors: Jeanclaude Combres, Lauriane Rouan, Isabelle Mialetserra, Jeanpierre Caliman, Benoit Pallas, Serge Braconnier, Jeanchristophe Soulie, Michael DingkuhnAbstract:For oil palm, yield variation is in large part due to variation in the number of harvested bunches. Each successively-produced Phytomer carries a female (productive), male or aborted inflorescence. Since Phytomer development takes 3–4 years and nearly two Phytomers are produced per month, many inflorescences develop in parallel but have different phenological stages. Environment-dependent developmental rate, sex and abortion probability determine bunch productivity, which, in turn, affects other Phytomers via source–sink relationships. Water deficit, solar radiation, temperature and day length are considered key external factors driving variation. Their impact is difficult to predict because of system complexity. To address this question we built a simple model (ECOPALM) to simulate the variation in number of harvested bunches. In this model, trophic competition among organs, expressed through a plant-scale index (Ic), drives sex determination and inflorescence abortion during specific sensitive phases at Phytomer level. As a supplemental hypothesis, we propose that flowering is affected by photoperiod at Phytomer level during a sensitive phase, thus, contributing to seasonal production peaks. The model was used to determine by parameter optimisation the influence of Ic and day length on inflorescence development and the stages at which inflorescences are sensitive to these signals. Parameters were estimated against observation of number of harvested bunches in Ivory Coast using a genetic algorithm. The model was then validated with field observations in Benin and Indonesia. The sensitive phases determined by parameter optimisation agreed with independent experimental evidence, and variation of Ic explained both sex and abortion patterns. Sex determination seemed to coincide with floret meristem individualisation and occurred 29–32 months before bunch harvest. The main abortion stage occurred 10 months before harvest – at the beginning of rapid growth of the inflorescence. Simulation results suggest involvement of photoperiod in the determination of bunch growth dynamics. This study demonstrates that simple modelling approaches can help extracting ecophysiological information from simple field observations on complex systems.
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phenology growth and physiological adjustments of oil palm elaeis guineensis to sink limitation induced by fruit pruning
Annals of Botany, 2009Co-Authors: Sandrine Legros, Denis Fabre, Anne Clementvidal, Isabelle Mialetserra, Jeanpierre Caliman, Fahri Arief Siregar, Michael DingkuhnAbstract:† Background and Aims Despite its simple architecture and small phenotypic plasticity, oil palm has complex phenology and source –sink interactions. Phytomers appear in regular succession but their development takes years, involving long lag periods between environmental influences and their effects on sinks. Plant adjustments to resulting source –sink imbalances are poorly understood. This study investigated oil palm adjustments to imbalances caused by severe fruit pruning. † Methods An experiment with two treatments (control and complete fruit pruning) during 22 months in 2006– 2008) and six replications per treatment was conducted in Indonesia. Phenology, growth of above-ground vegetative and reproductive organs, leaf morphology, inflorescence sex differentiation, dynamics of non-structural carbohydrate reserves and light-saturated net photosynthesis (Amax) were monitored. † Key Results Artificial sink limitation by complete fruit pruning accelerated development rate, resulting in higher Phytomer, leaf and inflorescence numbers. Leaf size and morphology remained unchanged. Complete fruit pruning also suppressed the abortion of male inflorescences, estimated to be triggered at about 16 months before bunch maturity. The number of female inflorescences increased after an estimated lag of 24 –26 months, corresponding to time from sex differentiation to bunch maturity. The most important adjustment process was increased assimilate storage in the stem, attaining nearly 50 % of dry weight in the stem top, mainly as starch, whereas glucose, which in controls was the most abundant non-structural carbohydrate stored in oil palm, decreased. † Conclusions The development rate of oil palm is in part controlled by source– sink relationships. Although increased rate of development and proportion of female inflorescences constituted observed adjustments to sink limitation, the low plasticity of plant architecture (constant leaf size, absence of branching) limited compensatory growth. Non-structural carbohydrate storage was thus the main adjustment process.
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phenology and growth adjustments of oil palm elaeis guineensis to photoperiod and climate variability
Annals of Botany, 2009Co-Authors: Sandrine Legros, Anne Clementvidal, Isabelle Mialetserra, Jeanpierre Caliman, Fahri Arief Siregar, Michael DingkuhnAbstract:† Background and Aims Oil palm flowering and fruit production show seasonal maxima whose causes are unknown. Drought periods confound these rhythms, making it difficult to analyse or predict dynamics of production. The present work aims to analyse phenological and growth responses of adult oil palms to seasonal and inter-annual climatic variability. † Methods Two oil palm genotypes planted in a replicated design at two sites in Indonesia underwent monthly observations during 22 months in 2006‐2008. Measurements included growth of vegetative and reproductive organs, morphology and phenology. Drought was estimated from climatic water balance (rainfall ‐ potential evapotranspiration) and simulated fraction of transpirable soil water. Production history of the same plants for 2001‐ 2005 was used for inter-annual analyses. † Key Results Drought was absent at the equatorial Kandista site (0855 0 N) but the Batu Mulia site (3812 0 S) had a dry season with variable severity. Vegetative growth and leaf appearance rate fluctuated with drought level. Yield of fruit, a function of the number of female inflorescences produced, was negatively correlated with photoperiod at Kandista. Dual annual maxima were observed supporting a recent theory of circadian control. The photoperiodsensitive phases were estimated at 9 (or 9 þ 12 � n) months before bunch maturity for a given Phytomer. The main sensitive phase for drought effects was estimated at 29 months before bunch maturity, presumably associated with inflorescence sex determination. † Conclusion It is assumed that seasonal peaks of flowering in oil palm are controlled even near the equator by photoperiod response within a Phytomer. These patterns are confounded with drought effects that affect flowering (yield) with long time-lag. Resulting dynamics are complex, but if the present results are confirmed it will be possible to predict them with models.
Bruno Andrieu - One of the best experts on this subject based on the ideXlab platform.
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Rose bush leaf and internode expansion dynamics: analysis and development of a model capturing interplant variability
Frontiers in Plant Science, 2013Co-Authors: Sabine Demotes-mainard, Jessica Bertheloot, Rachid Boumaza, Lydie Huche-thelier, Gaëlle Gueritaine, Vincent Guérin, Bruno AndrieuAbstract:Bush rose architecture, among other factors, such as plant health, determines plant visual quality. The commercial product is the individual plant and interplant variability may be high within a crop. Thus, both mean plant architecture and interplant variability should be studied. Expansion is an important feature of architecture, but it has been little studied at the level of individual organs in bush roses. We investigated the expansion kinetics of primary shoot organs, to develop a model reproducing the organ expansion of real crops from non destructive input variables. We took interplant variability in expansion kinetics and the model's ability to simulate this variability into account. Changes in leaflet and internode dimensions over thermal time were recorded for primary shoot expansion, on 83 plants from three crops grown in different climatic conditions and densities. An empirical model was developed, to reproduce organ expansion kinetics for individual plants of a real crop of bush rose primary shoots. Leaflet or internode length was simulated as a logistic function of thermal time. The model was evaluated by cross-validation. We found that differences in leaflet or internode expansion kinetics between Phytomer positions and between plants at a given Phytomer position were due mostly to large differences in time of organ expansion and expansion rate, rather than differences in expansion duration. Thus, in the model, the parameters linked to expansion duration were predicted by values common to all plants, whereas variability in final size and organ expansion time was captured by input data. The model accurately simulated leaflet and internode expansion for individual plants (RMSEP = 7.3% and 10.2% of final length, respectively). Thus, this study defines the measurements required to simulate expansion and provides the first model simulating organ expansion in rosebush to capture interplant variability.
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Plasticity of winter wheat modulated by sowing date, plant population density and nitrogen fertilisation: Dimensions and size of leaf blades, sheaths and internodes in relation to their position on a stem
Field Crops Research, 2011Co-Authors: Tino Dornbusch, Christian Fournier, Rim Baccar, Jillian Watt, Jonathan Hillier, Jessica Bertheloot, Bruno AndrieuAbstract:Mathematical models to describe crop-environment interaction on organ scale need to take crop or plant architecture into account. Up to now, architectural plant models are largely descriptive and parameters need to be estimated for each species, cultivar and environment. Required measurements are extensive and time-consuming. Hence investigating morphological patterns and their modulation as a response to environmental conditions may help to reduce measurement efforts and to predict plant architecture in crop models. In this paper, we describe the plasticity of winter wheat - expressed as the dimensions and sizes of leaf blades, sheaths and internodes in relation to their position on a stem - under the climatic conditions of the Paris region. Results are discussed with respect to: (i) genotypic variability, (ii) inter-annual variability, (iii) sowing date and plant population density, (iv) Nitrogen fertilisation and (v) tiller rank. Eight wheat cultivars grown in the same season showed similar patterns of leaf and internodes dimensions in relation to their position on the stem. For the cultivar 'Soissons', main stem architecture at flowering was remarkably stable when similar growth conditions were reproduced in the different seasons. Increased plant population density yielded longer juvenile, but shorter adult leaf blades and sheaths. Earlier sowing led to an increase in the number of juvenile Phytomers - growing before the onset of stem elongation - on the main stem, whereas the number of adult Phytomers was almost identical. Further there were little differences in the size of leaf blades, sheaths and internodes between the main stem and axillary tillers. We found remarkable differences in the size of adult leaf blades and sheaths in different growing seasons, with different timing of nitrogen fertilisation and we discuss decreased availability of nitrogen in the soil in spring as a likely cause. Data presented here can be used to enlarge the understanding of wheat plasticity regarding the regulation of organ size by temperature, light, plant-available nitrogen and size-mediated effects towards a mechanistic modelling of these responses.
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cessation of tillering in spring wheat in relation to light interception and red far red ratio
Annals of Botany, 2006Co-Authors: Jochem B Evers, Bruno Andrieu, P C StruikAbstract:? Background and Aims The production of axillary shoots (tillering) in spring wheat (Triticum aestivum) depends on intraspecific competition. The mechanisms that underlie this competition are complex, but light within the wheat canopy plays a key role. The main objectives of this paper are to analyse the effects of plant population density and shade on tillering dynamics of spring wheat, to assess the canopy conditions quantitatively at the time of tillering cessation, and to analyse the relationship between the tiller bud and the leaf on the same Phytomer. Methods Spring wheat plants were grown at three plant population densities and under two light regimes (25 % and 100 % light). Tiller appearance, fraction of the light intercepted, and red : far-red ratio at soil level were recorded. On six sampling dates the growth status of axillary buds was analysed. Key Results Tillering ceased earlier at high population densities and ceased earlier in the shade than in full sunlight. At cessation of tillering, both the fraction of light intercepted and the red : far-red ratio at soil level were similar in all treatments. Leaves on the same Phytomer of buds that grew out showed more leaf mass per unit area than those on the same Phytomer of buds that remained dormant. Conclusions Tillering ceases at specific light conditions within the wheat canopy, independent of population density, and to a lesser extent independent of light intensity. It is suggested that cessation of tillering is induced when the fraction of PAR intercepted by the canopy exceeds a specific threshold (0·40-0·45) and red : far-red ratio drops below 0·35-0·40
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towards a generic architectural model of tillering in gramineae as exemplified by spring wheat triticum aestivum
New Phytologist, 2005Co-Authors: Jochem B Evers, J Vos, Christian Fournier, Bruno Andrieu, Michael Chelle, P C StruikAbstract:Summary • This paper presents an architectural model of wheat (Triticum aestivum), designed to explain effects of light conditions at the individual leaf level on tillering kinetics. Various model variables, including blade length and curvature, were parameterized for spring wheat, and compared with winter wheat and other Gramineae species. • The architectural model enables simulation of plant properties at the level of individual organs. Parameterization was based on data derived from an outdoor experiment with spring wheat cv. Minaret. • Final organ dimensions of tillers could be modelled using the concept of relative Phytomer numbers. Various variables in spring wheat showed marked similarities to winter wheat and other species, suggesting possibilities for a general Gramineae architectural model. • Our descriptive model is suitable for our objective: investigating light effects on tiller behaviour. However, we plan to replace the descriptive modelling solutions by physiological, mechanistic solutions, starting with the localized production and partitioning of assimilates as affected by abiotic growth factors.
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Dynamics Of Internode And Stem Elongation In Three Cultivars Of Maize
Agronomie, 2002Co-Authors: Cj Birch, Bruno Andrieu, Christian FournierAbstract:The kinetics of elongation of individual internodes, the peduncle and panicle of maize were studied in field experiments in Gatton (Australia) using two tropical cultivars, and compared to similar data previously collected in Grignon (France) on a temperate cultivar. Data for Phytomer initiation and organ extension and appearance were related to thermal time calculated from the temperature in the growing zone. Extension of internodes was analysed using a four stage framework:- an initial exponential stage, transition to rapid extension, rapid (linear) extension and transition to final length. The kinetics of internode extension were similar in Gatton and Grignon, though the rates of processes differed. Transition from stage 1 to stage 2 coincided with collar emergence. The commencement of rapid extension of the peduncle coincided with a transient reduction in the rates of extension of vegetative internodes. Further work is needed to assess whether they are effects of genotype only, or genotype and environment.
Yuanchao Fan - One of the best experts on this subject based on the ideXlab platform.
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a sub canopy structure for simulating oil palm in the community land model clm palm phenology allocation and yield
Geoscientific Model Development, 2015Co-Authors: Yuanchao Fan, Olivier Roupsard, M Bernoux, Le G Maire, O Panferov, Martyna M Kotowska, Alexander KnohlAbstract:Abstract. In order to quantify the effects of forests to oil palm conversion occurring in the tropics on land–atmosphere carbon, water and energy fluxes, we develop a new perennial crop sub-model CLM-Palm for simulating a palm plant functional type (PFT) within the framework of the Community Land Model (CLM4.5). CLM-Palm is tested here on oil palm only but is meant of generic interest for other palm crops (e.g., coconut). The oil palm has monopodial morphology and sequential phenology of around 40 stacked Phytomers, each carrying a large leaf and a fruit bunch, forming a multilayer canopy. A sub-canopy phenological and physiological parameterization is thus introduced so that each Phytomer has its own prognostic leaf growth and fruit yield capacity but with shared stem and root components. Phenology and carbon and nitrogen allocation operate on the different Phytomers in parallel but at unsynchronized steps, separated by a thermal period. An important phenological phase is identified for the oil palm – the storage growth period of bud and "spear" leaves which are photosynthetically inactive before expansion. Agricultural practices such as transplanting, fertilization and leaf pruning are represented. Parameters introduced for the oil palm were calibrated and validated with field measurements of leaf area index (LAI), yield and net primary production (NPP) from Sumatra, Indonesia. In calibration with a mature oil palm plantation, the cumulative yields from 2005 to 2014 matched notably well between simulation and observation (mean percentage error = 3 %). Simulated inter-annual dynamics of PFT-level and Phytomer-level LAI were both within the range of field measurements. Validation from eight independent oil palm sites shows the ability of the model to adequately predict the average leaf growth and fruit yield across sites and sufficiently represent the significant nitrogen- and age-related site-to-site variability in NPP and yield. Results also indicate that seasonal dynamics of yield and remaining small-scale site-to-site variability of NPP are driven by processes not yet implemented in the model or reflected in the input data. The new sub-canopy structure and phenology and allocation functions in CLM-Palm allow exploring the effects of tropical land-use change, from natural ecosystems to oil palm plantations, on carbon, water and energy cycles and regional climate.
Alexander Knohl - One of the best experts on this subject based on the ideXlab platform.
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a sub canopy structure for simulating oil palm in the community land model clm palm phenology allocation and yield
Geoscientific Model Development, 2015Co-Authors: Yuanchao Fan, Olivier Roupsard, M Bernoux, Le G Maire, O Panferov, Martyna M Kotowska, Alexander KnohlAbstract:Abstract. In order to quantify the effects of forests to oil palm conversion occurring in the tropics on land–atmosphere carbon, water and energy fluxes, we develop a new perennial crop sub-model CLM-Palm for simulating a palm plant functional type (PFT) within the framework of the Community Land Model (CLM4.5). CLM-Palm is tested here on oil palm only but is meant of generic interest for other palm crops (e.g., coconut). The oil palm has monopodial morphology and sequential phenology of around 40 stacked Phytomers, each carrying a large leaf and a fruit bunch, forming a multilayer canopy. A sub-canopy phenological and physiological parameterization is thus introduced so that each Phytomer has its own prognostic leaf growth and fruit yield capacity but with shared stem and root components. Phenology and carbon and nitrogen allocation operate on the different Phytomers in parallel but at unsynchronized steps, separated by a thermal period. An important phenological phase is identified for the oil palm – the storage growth period of bud and "spear" leaves which are photosynthetically inactive before expansion. Agricultural practices such as transplanting, fertilization and leaf pruning are represented. Parameters introduced for the oil palm were calibrated and validated with field measurements of leaf area index (LAI), yield and net primary production (NPP) from Sumatra, Indonesia. In calibration with a mature oil palm plantation, the cumulative yields from 2005 to 2014 matched notably well between simulation and observation (mean percentage error = 3 %). Simulated inter-annual dynamics of PFT-level and Phytomer-level LAI were both within the range of field measurements. Validation from eight independent oil palm sites shows the ability of the model to adequately predict the average leaf growth and fruit yield across sites and sufficiently represent the significant nitrogen- and age-related site-to-site variability in NPP and yield. Results also indicate that seasonal dynamics of yield and remaining small-scale site-to-site variability of NPP are driven by processes not yet implemented in the model or reflected in the input data. The new sub-canopy structure and phenology and allocation functions in CLM-Palm allow exploring the effects of tropical land-use change, from natural ecosystems to oil palm plantations, on carbon, water and energy cycles and regional climate.
Jeanpierre Caliman - One of the best experts on this subject based on the ideXlab platform.
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simulation of inflorescence dynamics in oil palm and estimation of environment sensitive phenological phases a model based analysis
Functional Plant Biology, 2013Co-Authors: Jeanclaude Combres, Lauriane Rouan, Isabelle Mialetserra, Jeanpierre Caliman, Benoit Pallas, Serge Braconnier, Jeanchristophe Soulie, Michael DingkuhnAbstract:For oil palm, yield variation is in large part due to variation in the number of harvested bunches. Each successively-produced Phytomer carries a female (productive), male or aborted inflorescence. Since Phytomer development takes 3–4 years and nearly two Phytomers are produced per month, many inflorescences develop in parallel but have different phenological stages. Environment-dependent developmental rate, sex and abortion probability determine bunch productivity, which, in turn, affects other Phytomers via source–sink relationships. Water deficit, solar radiation, temperature and day length are considered key external factors driving variation. Their impact is difficult to predict because of system complexity. To address this question we built a simple model (ECOPALM) to simulate the variation in number of harvested bunches. In this model, trophic competition among organs, expressed through a plant-scale index (Ic), drives sex determination and inflorescence abortion during specific sensitive phases at Phytomer level. As a supplemental hypothesis, we propose that flowering is affected by photoperiod at Phytomer level during a sensitive phase, thus, contributing to seasonal production peaks. The model was used to determine by parameter optimisation the influence of Ic and day length on inflorescence development and the stages at which inflorescences are sensitive to these signals. Parameters were estimated against observation of number of harvested bunches in Ivory Coast using a genetic algorithm. The model was then validated with field observations in Benin and Indonesia. The sensitive phases determined by parameter optimisation agreed with independent experimental evidence, and variation of Ic explained both sex and abortion patterns. Sex determination seemed to coincide with floret meristem individualisation and occurred 29–32 months before bunch harvest. The main abortion stage occurred 10 months before harvest – at the beginning of rapid growth of the inflorescence. Simulation results suggest involvement of photoperiod in the determination of bunch growth dynamics. This study demonstrates that simple modelling approaches can help extracting ecophysiological information from simple field observations on complex systems.
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phenology growth and physiological adjustments of oil palm elaeis guineensis to sink limitation induced by fruit pruning
Annals of Botany, 2009Co-Authors: Sandrine Legros, Denis Fabre, Anne Clementvidal, Isabelle Mialetserra, Jeanpierre Caliman, Fahri Arief Siregar, Michael DingkuhnAbstract:† Background and Aims Despite its simple architecture and small phenotypic plasticity, oil palm has complex phenology and source –sink interactions. Phytomers appear in regular succession but their development takes years, involving long lag periods between environmental influences and their effects on sinks. Plant adjustments to resulting source –sink imbalances are poorly understood. This study investigated oil palm adjustments to imbalances caused by severe fruit pruning. † Methods An experiment with two treatments (control and complete fruit pruning) during 22 months in 2006– 2008) and six replications per treatment was conducted in Indonesia. Phenology, growth of above-ground vegetative and reproductive organs, leaf morphology, inflorescence sex differentiation, dynamics of non-structural carbohydrate reserves and light-saturated net photosynthesis (Amax) were monitored. † Key Results Artificial sink limitation by complete fruit pruning accelerated development rate, resulting in higher Phytomer, leaf and inflorescence numbers. Leaf size and morphology remained unchanged. Complete fruit pruning also suppressed the abortion of male inflorescences, estimated to be triggered at about 16 months before bunch maturity. The number of female inflorescences increased after an estimated lag of 24 –26 months, corresponding to time from sex differentiation to bunch maturity. The most important adjustment process was increased assimilate storage in the stem, attaining nearly 50 % of dry weight in the stem top, mainly as starch, whereas glucose, which in controls was the most abundant non-structural carbohydrate stored in oil palm, decreased. † Conclusions The development rate of oil palm is in part controlled by source– sink relationships. Although increased rate of development and proportion of female inflorescences constituted observed adjustments to sink limitation, the low plasticity of plant architecture (constant leaf size, absence of branching) limited compensatory growth. Non-structural carbohydrate storage was thus the main adjustment process.
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phenology and growth adjustments of oil palm elaeis guineensis to photoperiod and climate variability
Annals of Botany, 2009Co-Authors: Sandrine Legros, Anne Clementvidal, Isabelle Mialetserra, Jeanpierre Caliman, Fahri Arief Siregar, Michael DingkuhnAbstract:† Background and Aims Oil palm flowering and fruit production show seasonal maxima whose causes are unknown. Drought periods confound these rhythms, making it difficult to analyse or predict dynamics of production. The present work aims to analyse phenological and growth responses of adult oil palms to seasonal and inter-annual climatic variability. † Methods Two oil palm genotypes planted in a replicated design at two sites in Indonesia underwent monthly observations during 22 months in 2006‐2008. Measurements included growth of vegetative and reproductive organs, morphology and phenology. Drought was estimated from climatic water balance (rainfall ‐ potential evapotranspiration) and simulated fraction of transpirable soil water. Production history of the same plants for 2001‐ 2005 was used for inter-annual analyses. † Key Results Drought was absent at the equatorial Kandista site (0855 0 N) but the Batu Mulia site (3812 0 S) had a dry season with variable severity. Vegetative growth and leaf appearance rate fluctuated with drought level. Yield of fruit, a function of the number of female inflorescences produced, was negatively correlated with photoperiod at Kandista. Dual annual maxima were observed supporting a recent theory of circadian control. The photoperiodsensitive phases were estimated at 9 (or 9 þ 12 � n) months before bunch maturity for a given Phytomer. The main sensitive phase for drought effects was estimated at 29 months before bunch maturity, presumably associated with inflorescence sex determination. † Conclusion It is assumed that seasonal peaks of flowering in oil palm are controlled even near the equator by photoperiod response within a Phytomer. These patterns are confounded with drought effects that affect flowering (yield) with long time-lag. Resulting dynamics are complex, but if the present results are confirmed it will be possible to predict them with models.