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Ep Heuvelink - One of the best experts on this subject based on the ideXlab platform.
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Simulation of leaf area development based on Dry Matter Partitioning and specific leaf area for cut chrysanthemum.
Annals of botany, 2002Co-Authors: Jeong Hyun Lee, Ep HeuvelinkAbstract:This work aims to predict time courses of leaf area index (LAI) based on Dry Matter Partitioning into the leaves and on specific leaf area of newly formed leaf biomass (SLAn) for year‐round cut chrysanthemum crops. In five glasshouse experiments, each consisting of several plant densities and planted throughout the year, periodic destructive measurements were conducted to develop empirical models for Partitioning and for SLAn. Dry Matter Partitioning into leaves, calculated as incremental leaf Dry mass divided by incremental shoot Dry mass between two destructive harvests, could be described accurately (R2 = 0·93) by a Gompertz function of relative time, Rt. Rt is 0 at planting date, 1 at the start of short‐days, and 2 at final harvest. SLAn, calculated as the slope of a linear regression between periodic measurements of leaf Dry mass (LDM) and LAI, showed a significant linear increase with the inverse of the daily incident photosynthetically active radiation (incident PAR, MJ m–2 d–1), averaged over the whole growing period, the average glasshouse temperature and plant density (R2 = 0·74). The models were validated by two independent experiments and with data from three commercial growers, each with four planting dates. Measured shoot Dry mass increase, initial LAI and LDM, plant density, daily temperature and incident PAR were input into the model. Dynamics of LDM and LAI were predicted accurately by the model, although in the last part of the cultivation LAI was often overestimated. The slope of the linear regression of simulated against measured LDM varied between 0·95 and 1·09. For LAI this slope varied between 1·01 and 1·12. The models presented in this study are important for the development of a photosynthesis‐driven crop growth model for cut chrysanthemum crops.
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Modelling fruit set, fruit growth and Dry Matter Partitioning
Acta Horticulturae, 1999Co-Authors: Leo F. M. Marcelis, Ep HeuvelinkAbstract:This paper discusses how fruit set, fruit growth and Dry Matter Partitioning can be simulated by models where sink strength (assimilate demand) and source strength (assimilate supply) are the key variables. Although examples are derived from experiments on fruit vegetables such as tomato, sweet pepper and cucumber, the theoretical basis holds for a wide range of crops including fruit trees. Dry Matter Partitioning is the end result of the flow of assimilates from source organs via a transport path to the sink organs. It appears to be primarily regulated by the sink strength of the sinks, with fruits being the major sinks in fruit trees or fruit vegetables. Source strength has only an indirect effect on Dry Matter Partitioning through effects on the number of fruits on a plant. The transport path is only of minor importance for the regulation of Dry Matter Partitioning at the whole plant level. The growth rate of a fruit depends on the source strength and the fraction of the assimilates partitioned into it. Dry Matter Partitioning was modelled as a function of the sink strengths of the plant organs, where sink strength of an organ is defined by its potential growth rate (potential capacity to accumulate assimilates). The potential growth rate has been shown to quantitatively reflect the sink strength of an organ. The potential growth of a fruit is a function of both its age and temperature. In several experiments and for different treatments it was shown that Dry Matter Partitioning into a fruit can be simulated as a function of its sink strength relative to that of the other plant organs. The number of fruits set per plant has a great impact on the Dry Matter Partitioning and fruit growth. Several experiments have shown that fruit set increases with source strength and decreases with sink strength. Consequently fruit set could be reasonably successful modelled as a function of sink and source strength. Finally it is shown how a photosynthesis-based model combined with submodels for fruit set, fruit growth and Dry Matter Partitioning can be used for predictions of yield and fruit size.
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Dry Matter Partitioning in Tomato: Validation of a Dynamic Simulation Model
Annals of Botany, 1996Co-Authors: Ep HeuvelinkAbstract:Abstract A model for dynamic simulation of Dry Matter distribution between reproductive and vegetative plant parts and the distribution among individual fruit trusses in glasshouse tomato, is validated. The model is part of the crop growth model TOMSIM and is based on the hypothesis that Dry Matter distribution is regulated by the sink strengths of the plant organs, quantified by their potential growth rates, i.e. the growth rates at non-limiting assimilate supply. Within the plant, individual fruit trusses are distinguished and sink strength of a truss is described as a function of its development stage. Truss development rate is a function of temperature only. The same potential growth curve, proportional to the number of fruits per truss, is adopted for all trusses. In a simple version of the model, vegetative plant parts are lumped together as one sink with a constant sink strength. In a more detailed version, vegetative sink strength is calculated as the sum of sink strengths of vegetative units (three leaves and stem internodes between two trusses). The model was validated for six glasshouse experiments, covering effects of planting date, plant density, number of fruits per truss (pruning at anthesis), truss removal (every second truss removed at anthesis), single- and double-shoot plants and a temperature experiment conducted in climate rooms at 17, 20 or 23 °C. Daily increase in above-ground Dry weight, average daily temperatures and number of set fruits per truss were inputs to the model. Both the simple and the more detailed model showed good agreement between measured and simulated fraction of Dry Matter partitioned into the fruits over time. For the simple version of the model, the slope of the lines relating simulated to measured fraction partitioned into the fruits (16 data sets), varied between 0.92 and 1.11, on average it was 1.04, implying 4% over-estimation for this fraction. For the detailed model these numbers were slightly better: 0.89, 1.08 and 1.01, respectively. The temperature experiment revealed no important direct influence of temperature on the ratio between generative and vegetative sink strength. Simulated truss growth curves showed reasonable agreement with the measurements, although both models over-estimated (17% on average) final Dry weight of the lower trusses (truss 1 –3) on a plant. Modelling Dry Matter Partitioning based on sink strengths of organs is promising, as it is a general, dynamic and flexible approach, showing good agreement between measurements and simulation for a range of conditions. Applicability of the model is, however, still limited as long as the number of fruits per truss (flower and /or fruit abortion) is not simulated, as this is a major feedback mechanism in plant growth.
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Dry Matter Partitioning in a tomato plant: one common assimilate pool?
Journal of Experimental Botany, 1995Co-Authors: Ep HeuvelinkAbstract:The influence of the distance (transport resistance) between source and sink on Dry Matter distribution between fruits and vegetative parts in tomato was studied. In two glasshouse experiments, a control treatment (single-shoot plants, no truss removal) was conducted, together with two double-shoot treatments: double-shoot plants with no trusses removed from one shoot and all trusses removed at anthesis from the other shoot (100-0) and double-shoot plants with every second truss removed from both shoots (50-50). Plant growth and Dry Matter distribution was recorded by periodical destructive harvests, during a period of about 100 d after anthesis of the first truss. In Experiment 2, plants were probably sink-limited. At the end of both experiments, 58-60% of Dry Matter was in the fruits for control plants, whereas for both double-shoot treatments this was 43% (Experiment 1) or 38% (Experiment 2). Until 60-65 d after first flowering, vegetative growth of the individual shoots in both double-shoot treatments was the same. Results supported the assumption of one common assimilate pool and showed no significant influence of distance (transport resistance) between source and sink on Dry Matter Partitioning.
Christa M. Hoffmann - One of the best experts on this subject based on the ideXlab platform.
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Importance of canopy closure and Dry Matter Partitioning for yield formation of sugar beet varieties
Field Crops Research, 2019Co-Authors: Christa M. HoffmannAbstract:Abstract Phenotyping of sugar beet canopy for yield estimate requires a close relationship between canopy characteristics and final sugar yield. The objective of the study was to identify the importance of early canopy closure and of Dry Matter Partitioning for high sugar yields, or more general, to study whether sugar beet yield is limited more by the source or by the sink capacity. Randomized field trials were conducted with two varieties (sugar type, yield type) in three sowing dates and four harvest dates at two sites in three years (2012–2014). Results showed very stable variety characteristics for all parameters and a linear increase of sugar yield with thermal time from September to November. Although variety 2 had reached canopy closure 100 GDD later and had a lower LAI and leaf yield than variety 1 throughout the growing season, it reached a higher sugar yield. That could be attributed to a higher RUE and a higher fraction of Dry Matter partitioned to sugar storage, while total Dry Matter did not differ distinctly. In the storage root, more cambial rings were formed, indicating a higher sink strength. Hence, sugar yield is more determined by Dry Matter Partitioning (sink) than by canopy formation (source), making phenotyping difficult.
Elias Fereres - One of the best experts on this subject based on the ideXlab platform.
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Planting density effects on Dry Matter Partitioning and productivity of sunflower hybrids
Field Crops Research, 1994Co-Authors: Francisco J. Villalobos, Victor O. Sadras, A. Soriano, Elias FereresAbstract:Abstract Dry Matter Partitioning and yield formation are key points for successful simulation of seed yield. The response of Dry Matter Partitioning and yield of sunflower (Helianthus annuus L.) to plant population was studied in field experiments performed at Cordoba, Spain in 1990 and 1991. Four hybrids (SW-101, Arbung E353, Sungro 385 and S530) were grown under irrigation at plant populations ranging from 0.5 to 10 plants m−2. The hybrids differed in the durations of the emergence-floral initiation (FI) and FI-anthesis periods but not in the duration of seed filling. The responses of biomass, seed number and yield to planting density were dependent on the hybrid. The leaf Partitioning coefficient decreased and the head Partitioning coefficient increased with increasing plant population, suggesting that the head has a priority for Dry Matter Partitioning. The number of seeds per head changed with plant population through changes in the number of flowers and in the fertility ratio of the central part of the capitulum. Single-seed mass decreased with increasing planting density while the amount of oil per seed was little affected, showing the dependence of oil accumulation on factors other than carbohydrate supply. Seed yield response to planting density followed a saturation-type curve with the plateau around 4.5 t ha−1, indicating that potential yields under irrigation can be achieved by using short-cycle cultivars if plant population is high enough. Increasing potential yield of the sunflower should focus on the improvement of the harvest index of the long-cycle hybrids.
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Effects of shading on Dry Matter Partitioning and yield of field-grown sunflower
European Journal of Agronomy, 1992Co-Authors: Francisco J. Villalobos, A. Soriano, Elias FereresAbstract:Abstract Crop simulation models require quantitative descriptions of the effects of irradiance on Dry Matter partition and yield. The objective of this work was to quantify the effects of reduced radiation intensity during different phenological stages on the growth, Dry Matter Partitioning and grain numbers of sunflower (Helianthus annuus, L.). A field experiment was carried out in 1990 with 50 per cent shading treatments. The earliest treatment began at crop emergence while the latest ended at first anthesis. Shading had little effect on plant leaf area growth but reduced biomass and yield. The Dry Matter: radiation quotient and specific leaf area increased with shading. Grain number per head was decreased by shading, with the greatest effect occurring when shading was applied prior to anthesis. All shading treatments increased Dry Matter Partitioning to stems, decreased assimilate Partitioning to the heads and had no effect on the Partitioning to leaves.
Francisco J. Villalobos - One of the best experts on this subject based on the ideXlab platform.
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Planting density effects on Dry Matter Partitioning and productivity of sunflower hybrids
Field Crops Research, 1994Co-Authors: Francisco J. Villalobos, Victor O. Sadras, A. Soriano, Elias FereresAbstract:Abstract Dry Matter Partitioning and yield formation are key points for successful simulation of seed yield. The response of Dry Matter Partitioning and yield of sunflower (Helianthus annuus L.) to plant population was studied in field experiments performed at Cordoba, Spain in 1990 and 1991. Four hybrids (SW-101, Arbung E353, Sungro 385 and S530) were grown under irrigation at plant populations ranging from 0.5 to 10 plants m−2. The hybrids differed in the durations of the emergence-floral initiation (FI) and FI-anthesis periods but not in the duration of seed filling. The responses of biomass, seed number and yield to planting density were dependent on the hybrid. The leaf Partitioning coefficient decreased and the head Partitioning coefficient increased with increasing plant population, suggesting that the head has a priority for Dry Matter Partitioning. The number of seeds per head changed with plant population through changes in the number of flowers and in the fertility ratio of the central part of the capitulum. Single-seed mass decreased with increasing planting density while the amount of oil per seed was little affected, showing the dependence of oil accumulation on factors other than carbohydrate supply. Seed yield response to planting density followed a saturation-type curve with the plateau around 4.5 t ha−1, indicating that potential yields under irrigation can be achieved by using short-cycle cultivars if plant population is high enough. Increasing potential yield of the sunflower should focus on the improvement of the harvest index of the long-cycle hybrids.
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Effects of shading on Dry Matter Partitioning and yield of field-grown sunflower
European Journal of Agronomy, 1992Co-Authors: Francisco J. Villalobos, A. Soriano, Elias FereresAbstract:Abstract Crop simulation models require quantitative descriptions of the effects of irradiance on Dry Matter partition and yield. The objective of this work was to quantify the effects of reduced radiation intensity during different phenological stages on the growth, Dry Matter Partitioning and grain numbers of sunflower (Helianthus annuus, L.). A field experiment was carried out in 1990 with 50 per cent shading treatments. The earliest treatment began at crop emergence while the latest ended at first anthesis. Shading had little effect on plant leaf area growth but reduced biomass and yield. The Dry Matter: radiation quotient and specific leaf area increased with shading. Grain number per head was decreased by shading, with the greatest effect occurring when shading was applied prior to anthesis. All shading treatments increased Dry Matter Partitioning to stems, decreased assimilate Partitioning to the heads and had no effect on the Partitioning to leaves.
Hartmut Stützel - One of the best experts on this subject based on the ideXlab platform.
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root growth and Dry Matter Partitioning of cauliflower under drought stress conditions measurement and simulation
European Journal of Agronomy, 2004Co-Authors: Henning Kage, M Kochler, Hartmut StützelAbstract:Field and container experiments were carried out in order to quantify root growth and Dry Matter Partitioning of cauliflower under drought stress conditions. Drought stress did not influence allometric relationships between leaf and stem Dry Matter and shoot and tap root Dry Matter. Drought stress, however, had an impact on the sink strength of the curd, thereby curd growth was delayed and curd Dry Matter production was more seriously depressed by a limited water supply than total Dry Matter. Drought stress did not modify a linear relationship between shoot Dry Matter and total root length, however, the specific root length of cauliflower was lower under drought stress conditions leading to a higher Dry Matter deposition in the fine root fraction. Also the vertical increment of rooting depth per degree day almost doubled under drought stress conditions. An existing model for Dry Matter Partitioning in cauliflower was adopted to include the effects of drought stress on Dry Matter Partitioning to the curd. Therefore, the initial increase of the curd's sink strength was made dependent on the plants relative growth rate during the vernalisation period. Furthermore, a simple descriptive root growth model was adopted to include drought stress impact on root growth. For this purpose the increase of rooting depth per degree day and the specific root length were made dependent on the average soil water potential in the rooted soil profile. The modified model modules predicted Dry Matter Partitioning and described the root length distribution of cauliflower sufficiently well using total Dry Matter production rate as input values.
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Predicting Dry-Matter Partitioning between individual cauliflower leaves using a source limitation/sink hierarchy model
The Journal of Horticultural Science and Biotechnology, 2003Co-Authors: Henning Kage, C. Alt, M Kochler, Hartmut StützelAbstract:SummaryData from a container and two field experiments were used to construct a model which describes Dry-Matter Partitioning between individual leaves of cauliflower. Thereby a combined source limitation/sink hierarchy approach is applied, assuming early sink-limited exponential growth followed by a source-limited growth phase. Increasing competition for assimilates from newly formed leaves with higher sink priority then decreases the availability of assimilates and determines the end of the growth phase of an individual leaf. Leaf senescence is assumed to start when the growth rate of an individual leaf approaches zero. The end of senescence, i.e. the time of leaf death, is described using an empirical temperature sum function. The model was able to describe (r2 = 0.97) and predict (r2 = 0.90 and 0.87) the Partitioning of Dry Matter between classes of leaves consisting of three and five individuals for the container and the field experiments, respectively. The parameter estimates obtained indicate that ...
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Nitrogen Status and Light Environment Influence Dry Matter Partitioning in Cauliflower
Journal of the American Society for Horticultural Science, 2001Co-Authors: C. Alt, Henning Kage, Hartmut StützelAbstract:Concepts of above-ground Dry Matter Partitioning in cauliflower ( Brassica oleracea L. (Botrytis Group)) as dependent on nitrogen (N) supply and light environment are presented. Leaf and stem Partitioning depends on a functional relationship between stem Dry weight and leaf area, independent of N status. Dry Matter Partitioning into the inflorescence is sink-limited (potential capacity) at the beginning, and source limited (daily available assimilates) later. The intrinsic specific growth rate of the inflorescence is dependent on leaf N content. The model is parameterized and evaluated with data from field experiments. Applied to an independent data set, the model predictions of proportions of inflorescence, leaf, and stem on total Dry Matter corresponded with measurements ( r = 0.84, 0.92 and 0.22, respectively) for different N fertilization rates and light treatments. ing environmental conditions. Models for development and Dry
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A simple empirical model for predicting development and Dry Matter Partitioning in cauliflower (Brassica oleracea L. botrytis)
Scientia Horticulturae, 1999Co-Authors: Henning Kage, Hartmut StützelAbstract:Abstract An empirical model derived from data of field experiments is presented that predicts development and Dry Matter Partitioning in cauliflower under conditions of unrestricted nutrient and water supply. The model is a combination of an empirical relationship between temperature sum and leaf number, a vernalisation model, an allometric approach of Dry Matter Partitioning between leaf and stem and an empirical logistic function describing the fraction of Dry Matter allocated to the curd depending on the temperature sum after the end of the vernalisation process. This model was incorporated in a simple Dry Matter production model which calculated Dry Matter production using the product of intercepted photosynthetic active radiation and light use efficiency. However, the parameter values light use efficiency and specific leaf area of the model had to be fitted to every experiment in order to get an acceptable description of cauliflower Dry Matter production. Applied to an independent data set the model was able to predict measurable parameters like leaf number ( r 2 = 0.73), the proportion of leaf, stem and curd on total Dry Matter ( r 2 = 0.55, 0.08 and 0.77) and the length of the growing season ( r 2 = 0.69).
