Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Missing heritability and soft inheritance of morphology and metabolism in Arabidopsis
Kooke, R. - \ 2014
Wageningen University. Promotor(en): Harro Bouwmeester; Joost Keurentjes, co-promotor(en): Dick Vreugdenhil. - Wageningen University : Wageningen University - ISBN 9789462570412 - 283
arabidopsis - heritability - overerving - plantenmorfologie - metabolisme - plantenfysiologie - genetica - epigenetica - genetische variatie - arabidopsis - heritability - inheritance - plant morphology - metabolism - plant physiology - genetics - epigenetics - genetic variation

The plant phenotype is shaped by complex interactions between its genotype and the environment. Although the genotype is stable and determined by the genomic sequence, plants are able to respond flexibly to changes in environmental conditions by orchestrated signal transduction pathways. The genomic sequence may change with each generation through chromosome rearrangements, meiotic recombination and spontaneous mutations. Through natural selection on these randomly induced changes, genotypes become adapted to their local environment. Because different genotypes adapt to different environments, natural variation within species expands in time and gives rise to a wide variety of genotypes and phenotypes. The genetic architecture that specifies the phenotype can be investigated by analyzing different genotypes in the same environment and associate the phenotypic variation with molecular markers that discriminate the genotypes. Recent advances in next-generation sequencing technology enabled the fast sequencing of entire genomes, and in Arabidopsisthalianaalone, more than 1000 different genotypes have been fully resequenced. The sequencing allows the association of phenotypic variation with large numbers of single nucleotide polymorphisms (SNPs) that greatly enhance resolution in genome-wide association studies (GWAS).

GWAS on human diseases suffer from missing heritability that is most likely caused by the genetic architecture of the disease traits. Many variants of small effect or rare variants most likely determine a large part of the genetic variation and these variants are difficult to identify in GWAS due to lack of statistical power. In plants, several GWAS have been performed and they have identified previously validated genes and genes involved in monogenic disease resistance, but elucidating quantitative traits such as many agronomic important traits might be problematic in plants as well. Chapter 2 describes a GWA study in which quantitative morphological traits, such as leaf area, flowering time and branching were examined in 350 accessions of Arabidopsis for association with about 200,000 SNPs. The morphological traits showed extensive variation and were highly heritable, but GWA mapping could not identify the genetic variants that explain the heritability. Therefore, missing heritability was addressed using genomic selection models and these models confirmed the quantitative complex architecture of the morphological traits. Based upon these results, the heritability was assumed to be hidden below the significance threshold, and indeed lowering the significance threshold enabled the identification of many candidate genes that have been implicated to play a role in the phenotype directly or indirectly, in previous studies. One candidate gene was studied in more detail; natural variants of ACS11, an ethylene biosynthesis gene, associated significantly with the petiole to leaf length ratio. ACS11is indeed expressed in petioles and ectopically supplied ethylene abolished the difference in the phenotype of natural variants at this locus, strongly suggesting that ACS11is involved in the regulation of petiole growth.

However, lowering the significance threshold also increases the number of false-positive associations, non-causal alleles that co-segregate with the trait values. Because regulation of the morphological traits occurs at multiple intermediate levels, increased certainty on the associations can be obtained by performing GWA mapping on the intermediate levels from genotype to phenotype such as gene expression, and protein and metabolite content. Chapter 3 describes a literature survey into the multi-dimensional regulation of metabolic networks that are regulated by inputs from the clock, the communication between cells and between source and sink tissues, and the environment. The metabolic status of the plant can be seen as the final product of the interaction with the environment, and as such, it can serve as a blueprint for growth and development. Chapter 4 describes the abundant variation in enzyme activities and metabolites involved in primary carbon and nitrogen metabolism. The metabolite and enzyme activity data were analyzed together with plant biomass data, and many pleiotropic regulators were identified with opposite effects on primary metabolism and biomass formation. Natural variants in two stress-responsive genes were oppositely associated with biomass and many enzymes and metabolites involved in primary metabolism, suggesting that higher enzyme activities and higher levels of sugars and proteins might be needed to support plant resistance to stress at the expense of growth.

Some studies indicated that epigenetic variation, independent of the genetic SNPs, may contribute to missing heritability. Epigenetic inheritance is defined as the inheritance of phenotypic variation to future generations without changes in DNA sequence. Epigenetic variation is caused by variation in chromatin marks such as DNA methylation, histone modifications and small RNAs. Recently, a recombinant inbred line (RIL) population was developed in Arabidopsis where the chromosomes are differentially methylated in lines with an otherwise isogenic background by crossing wild-type Col-0 with a hypomethylated ddm1-2mutant. Chapter 5 describes the epigenetic regulation of morphology and phenotypic plasticity by studying morphological variation in 99 epiRILs under control and saline conditions. The morphology and plasticity trait values were associated with differentially methylated regions (DMRs) that were used as molecular markers in QTL mapping. Many QTLs for various morphological traits and phenotypic plasticity parameters co-located, suggesting pleiotropic epigenetic regulation of growth, morphology and plasticity. Furthermore, methylation variation in the promoter of a salt-tolerance gene, HIGH-AFFINITY K+TRANSPORTER1 (HKT1)associated significantly with leaf area, especially under saline conditions.

To gain more insight into the epigenetic regulation of plant growth and morphology, chapter 6 describes the epigenetic regulation of secondary metabolite levels in leaves and flowers and studies the relationship with the morphological traits determined in chapter 5. Many of the QTLs that were found for growth and morphology overlapped with the QTLs for metabolic traits, and suggest pleiotropic regulation. Furthermore, subsets of the metabolites correlated well with the morphological traits and might thus be regulated by the same loci. The majority of metabolite QTLs was detected for glucosinolates and flavonoids in the flowers, and methylation variation was observed for some of the biosynthetic pathway genes of these compounds when comparing Col-0 and ddm1-2, which indicates a role for epigenetic regulation of these biosynthesis pathways.

Although stable, natural epialleles have been found in plant species and the environment can induce hypo- and hypermethylation of DNA, it remains elusive whether environmentally-induced epigenetic changes can be inherited to subsequent generations, independent of genetic variation. Chapter 7 describes the transgenerational inheritance of phenotypic variation in progeny derived from a common Arabidopsis founder line. The progeny of stressed parents and grandparents showed variation in morphological traits, metabolite accumulation and gene expression. For example, many salt-responsive genes were up-regulated in progeny of salt-stressed grandparents. The responses to biotic (methyljasmonate) and abiotic (salt) stress differed strongly and this suggests that different environments can cause different transgenerational responses. Because all lines are derived from a single ancestor, epigenetic variation and not DNA variation is most likely causal for the phenotypic variation. Further studies are, however, needed to provide conclusive evidence for transgenerational inheritance.

Chapter 8 provides a synthesis of the work and discusses the GWA studies in the light of missing heritability, genetic architecture and the verification of candidate genes. The work on epigenetic regulation of phenotypic plasticity, morphology and metabolism is discussed in relation to Lamarckian soft inheritance that gained new enthusiasm after some recent discoveries in the field of epigenetics. And finally, the metabolomics work is discussed in the light of the growth-defense hypothesis that states that investments in defense occur at the expense of growth.

CO2 niet meer dan genoeg: Teelt van Tomaat in 2012 bij Improvement Centre met lichtafhankelijk doseren van CO2
Gelder, A. de; Warmenhoven, M.G. ; Dieleman, J.A. ; Klapwijk, P. ; Baar, P.H. van - \ 2014
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 1290)
glastuinbouw - tomaten - solanum lycopersicum - energiegebruik - kooldioxide - plantenmorfologie - kennisoverdracht - plantenontwikkeling - cultuurmethoden - proeven op proefstations - lichtsterkte - greenhouse horticulture - tomatoes - energy consumption - carbon dioxide - plant morphology - knowledge transfer - plant development - cultural methods - station tests - light intensity
Wageningen UR Glastuinbouw heeft met financiering van Kas als Energiebron en Samenwerken aan Vaardigheden onderzoek gedaan naar efficienter gebruik van CO2. In een kasproef bij GreenQ/Improvement Centre is een CO2 doseerstrategie getest, waarbij iets meer CO2 wordt gegeven dan er op basis van de hoeveelheid licht wordt opgenomen. Dit zorgt ervoor dat de CO2 concentratie in de kas bij open luchtramen net iets boven de buitenwaarde uit komt. Met deze doseerstrategie is met 17 kg/m² CO2 een productie gerealiseerd van 62.5 kg/m² tomaat (cultivar Komeett). Het energie gebruik was 26 m3/m². Uit de literatuur blijkt dat de weerstand die CO2 ondervindt vanuit de omgeving tot in de chloroplast, bij huidmondjes die voldoende openstaan, voor 40% bepaald wordt door het transport van CO2 door de celwand en het celvocht en voor 60% door de diffusie weerstand van kaslucht naar de intercellulaire ruimte. Een dun blad met veel sponsparenchym is daarom gunstig voor de CO2 binding. Het aantal huidmondjes per cm2 blad is daarbij minder maatgevend. Sluiting van de huidmondjes remt de fotosynthese binnen een minuut omdat de CO2 in het blad snel wordt opgebruikt. Vergelijking van de bladstructuur op twee hoogtes in het gewas met planten van hetzelfde ras in een andere proef lieten geen verschillen zien, niet in hoogte en niet in behandeling. Wageningen UR Greenhouse Horticulture developed a CO2 supply strategy in which slightly more CO2 is given than is taken up based on the amount of light. A test at GreenQ Improvement Centreresulted in a CO2 concentration in the greenhouse with open windows slightly above the outside value. With this supply strategy, 17 kg/m² CO2 supply resulted in a production level of 62.5 kg/m² tomato (cultivar Komeett). The energy consumption is 26 m3/m². When the stomata are open, the resistance of CO2 on the way from the environment into the chloroplast is for 40% determined by the transport of CO2 through the cell wall and the cytosol and for 60% by the diffusion resistance of greenhouse air to the intercellular space . A thin leaf with lots of spongy parenchym is therefore beneficial for CO2 binding. The number of stomata per cm2 leaf is therefore less important. Closing of the stomata inhibits photosynthesis within a minute because the CO2 in the leaf is then depleted. Comparison of the leaf structure at two heights in the crop with plants of the same variety in another compartment did not show differences, neither in height nor in treatment. This project was financed by Kas als Energiebron and Samenwerken aan Vaardigheden.
Characterization of African Bush Mango trees with emphasis on the differences between sweet and bitter trees in the Dahomey Gap (West Africa)
Vihotogbe, R. - \ 2012
Wageningen University. Promotor(en): Marc Sosef; B. Sinsin, co-promotor(en): Ronald van den Berg. - [S.l. : S.n. - ISBN 9789461734129 - 189
irvingia - domesticatie - bomen - plantenmorfologie - plantengeografie - genetische diversiteit - taxonomie - smaken - benin - west-afrika - irvingia - domestication - trees - plant morphology - phytogeography - genetic diversity - taxonomy - tastes - benin - west africa
An ecogeographic analysis of Oryza series Sativae in Asia and the Pacific
Banaticla-Hilario, M.C.N. - \ 2012
Wageningen University. Promotor(en): Marc Sosef, co-promotor(en): Ronald van den Berg; K.L. McNally. - S.l. : s.n. - ISBN 9789461733788 - 237
oryza - oryza sativa - oryza nivara - genetische bronnen van plantensoorten - plantengeografie - plantenecologie - diversiteit - in-situ conservering - plantenmorfologie - taxonomie - genetica - genenbanken - azië - oryza - oryza sativa - oryza nivara - plant genetic resources - phytogeography - plant ecology - diversity - in situ conservation - plant morphology - taxonomy - genetics - gene banks - asia

The non-cultivated speciesof the genus Oryza can provide a genetic arsenal of useful traits for improving the widely cultivated and consumed Asian rice (O. sativa). The diversity of these valuable plant resources must be well understood to ensure their effective in- and ex-situ conservation. In this thesis, we examined the ecogeographic variations within and between the three species of Oryza series Sativae in Asia and the Pacific. We looked at species differentiation from different spatial scales by analysing sympatric accession pairs of O. meridionalis and O. rufipogon and of O. nivara and O. rufipogon.

We conducted phenotypic analyses in Chapter 2. The strong influence of ecology on species morphology was demonstrated in the ordination and cluster analyses results where O. meridionalis and O. nivara grouped together and were separated from O. rufipogon. We detected greater differentiation of O. nivara and O. rufipogon in South Asia and positive correlations between spatial and intraspecific (interpopulation) morphological distances in continental Asia. We found significant correlations between geoclimatic factors and certain character measurements within species and observed that seedling height, culm number and diameter, leaf size, and anther length exhibit contrasting responses for O. nivara and O. rufipogon. We confirmed significant morphological differences between the three species, between the South and Southeast Asian populations of O. nivara, and between the Australasian and the non-Australasian populations of O. rufipogon and provided botanical descriptions to delineate O. meridionalis, O. nivara and O. rufipogon morphologically.

In Chapter 3, we genotyped the same set of accessions with 29 SSR markers and applied a variety of methods for genetic diversity analysis. Based on ordination and phylogenetic results, we verified that O. meridionalis is a genetically distinct species and that O. nivara and O. rufipogon overlap genetically across their geographic distribution. However, Bayesian clustering analysis recognized local-scale species separation of O. nivara and O. rufipogon implying stronger interspecific gene flow barriers in smaller spatial units. Concurrently, AMOVA indicated that the bulk (64%) of genetic variation in Asia Pacific series Sativae can be found among accessions and the lesser portions within accessions (26%) and among species (10%). We captured contrasting intraspecific variation patterns for O. nivara and O. rufipogon where the former exhibited low diversity, high population differentiation and isolation by distance mainly in South Asia while the latter displayed high diversity, low population differentiation and isolation by distance primarily in continental Southeast Asia. We established that altitude is correlated negatively to accession diversity and positively to local-scale species differentiation. Using Bayesian inference, we identified eight genetically distinct population groups: C1) Indian and Bangladeshi O. nivara; C2) Cambodian O. nivara; C3) Southeast Asian O. rufipogon; C4) O. meridionalis; C5) Nepalese O. nivara; C6) non-Cambodian Southeast Asian O. nivara; C7) Australasian O. rufipogon; and C8) South Asian O. rufipogon. Cluster analysis grouped the aromatic and japonica cultivar groups of O. sativa with O. rufipogon in South Asia and the indica and aus groups with O. nivara from Thailand and Cambodia, respectively. O. nivara from Nepal seemed genetically isolated from the other population groups. We also detected variation patterns that agreed with the results in Chapter 1 such as the South and Southeast Asian divisions of O. nivara, the divergence of Australasian populations from the rest of O. rufipogon and the greater differentiation of O. nivara and O. rufipogon in South Asia.

In Chapter 4, we conducted artificial crossing experiments to 15 selected parental accessions of O. meridionalis, O. nivara, and O. rufipogon and assessed the extent of several post-pollination isolating mechanisms in Oryza series Sativae. We observed reproductive incompatibility within and between the inbreeding species O. meridionalis and O. nivara and high intraspecific crossability of the outcrossing O. rufipogon where viable and non-sterile F1 hybrids were produced only by combinations with a parental distance that ranged from 1062 to 3813 kilometers. Insular Southeast Asian and/or Australasian accessions of O. rufipogon were the most reproductively successful parents. O. rufipogon exhibited significant pre-zygotic species isolation (in terms of seed set) and reduced post-zygotic isolation, and seemed symmetrically compatible with O. nivara and asymmetrically compatible with O. meridionalis. We obtained few annual hybrids with relatively high fertilities from crosses between O. rufipogon and O. nivara and numerous perennial hybrids with low fertilities from crosses between O. rufipogon and O. meridionalis. Crossability estimates did not show significant correlations with geographic distance between parents. However, we discerned reduced seed set and F1 fertility in interspecific combinations with sympatric parents compared to crosses with non-sympatric parents, indicative of reinforced species isolation in sympatry. We evaluated the F1 offspring of different cross combinations and found a mixture of intermediate and parental character traits in interspecific hybrids.

We discussed the taxonomic implications of the research results in Chapter 5 where we specifically dealt with the opposing views of lumping or splitting of O. nivara and O. rufipogon. We concluded that these two taxadeserve to be treated as separate species based on the following biosystematic evidence obtained from the thesis: 1) ecological distinction; 2) considerable prezygotic barriers; 3) opposing patterns of gene flow and genetic variation; 4) local-scale genetic divergence and 5) enhanced reproductive barriers under sympatric conditions. We identified ecogeography as a major driving force in the diversification of Oryza series Sativae in Asia and the Pacific and suggested that ecological speciation gave rise to O. nivara and O. rufipogon. We also presented recognizable geographic races within species.

Ultimately in Chapter 6, we emphasized the importance of our study in several aspects of rice science and identified results that agreed with prior Oryza diversity studies. At the same time, we presented previously unreported morphological and genetic variation patterns that were established in this thesis. We discussed the possible applications of the research results to wild rice conservation, covering in situ strategies as well as gene bank practices. We also highlighted the potential role of O. nivara in Asian rice domestication where it could have either directly given rise to the indica cultivar group or hybridized/introgressed with migrated japonica cultivars in India, eventually leading to the development of indica.

Plant Resources of Tropical Africa 16 Fibres
Brink, M. ; Achigan-Dako, E.G. - \ 2012
Wageningen, Netherlands : PROTA Foundation/CTA (Plant resources of tropical Africa 16) - ISBN 9789290814818 - 602
vezelgewassen - plantenvezels - soorten - genetische bronnen van plantensoorten - plantengeografie - plantenmorfologie - biologische naamgeving - taxonomie - plantenvermeerdering - tropisch afrika - fibre plants - plant fibres - species - plant genetic resources - phytogeography - plant morphology - biological nomenclature - taxonomy - propagation - tropical africa
This volume deals with the fibres of Tropical Africa. 515 ‘primary use’ fibres are described in 248 review articles. Many of the articles are illustrated with a geographic distribution map and a line drawing of the habit.
MADS on the move : a study on MADS domain protein function and movement during floral development in Arabidopsis thaliana
Urbanus, S.L. - \ 2010
Wageningen University. Promotor(en): Gerco Angenent, co-promotor(en): Richard Immink. - S.l. : S.n. - ISBN 9789085856245 - 138
arabidopsis thaliana - biologische ontwikkeling - bloemen - eiwitten - transcriptie - transcriptiefactoren - genexpressie - plantenmorfologie - eiwittransport - arabidopsis thaliana - biological development - flowers - proteins - transcription - transcription factors - gene expression - plant morphology - protein transport
In this thesis we investigated the behaviour of fluorescently-tagged MADS domain proteins during floral development in the model plant Arabidopsis thaliana, and explored the importance of intercellular transport via plasmodesmata for MADS domain transcription factor functioning. The MADS domain transcription factor family plays an important regulatory role in the development of flowers, among others by establishing the identities of the different floral organs. Although genetic screens and in vitro and in vivo studies on protein-protein and protein-DNA interactions provide important information on how MADS domain transcription factor complexes are able to regulate downstream target genes, understanding of the behaviour of MADS domain transcription factors in planta is still limited. Also, the extent to which intercellular movement of MADS domain transcription factors via plasmodesmata plays a role in developmental processes is poorly understood. Since the discovery of the GREEN FLUORESCENT PROTEIN (GFP) and the subsequent development of similar fluorescent tags, it has become possible to observe the subcellular localisation and behaviour of fluorescently-tagged proteins in living tissues with confocal laser scanning microscopy.
In Chapter 2 of this thesis, different methods of tagging the MADS domain transcription factors AGAMOUS (AG), SEPALLATA3 (SEP3), and FRUITFULL (FUL) for chromatin immunoprecipitation, chromatin affinity purification and in planta imaging are described. This research shows that the addition of a small peptide tag or a fluorescent tag to MADS domain proteins easily leads to transgene silencing and specific loss-of-function mutant phenotypes, especially when the tagged MADS box genes are expressed under the control of the constitutive CaMV35S promoter. Plants that express tagged MADS box genes from genomic fragments that include all or most of the regulatory elements, and therefore mimic the natural expression pattern as much as possible, show lower levels of loss-of-function phenotypes. In addition, these plants are also more useful for investigating biological relevant behaviour of the MADS domain proteins.
In Chapter 3, the spatio-temporal localisation patterns of GFP-tagged MADS domain transcription factors AG, SEP3, FUL and APETALA1 (AP1) during floral development are reported. These analyses demonstrate that there are several tissues, often epidermal cell layers, where MADS domain proteins could be detected, while the available literature describes an absence of mRNA in those tissues. This could indicate that there is intercellular transport of MADS domain proteins in meristematic tissues during floral development. The implications of the observed behaviour of the different MADS domain proteins for MADS domain protein functioning are discussed in this chapter.
In Chapters 4 and 5 we describe the different methods that were used to investigate whether MADS domain proteins are indeed able to transport between cells during floral development. The difficulties that we encountered in our attempts to investigate intercellular MADS domain protein transport with microinjection techniques and by using the photoconvertible fluorescent mEosFP-tag are discussed. In plants that specifically overexpress GFP-tagged MADS domain transcription factors AG, SEP3, APETALA3 (AP3), or PISTILLATA (PI) in the epidermis, we demonstrated with a photobleaching technique that all tested proteins were able to move within the epidermal cell layer. This mechanism of lateral epidermal movement provides an explanation for most of the unexpected MADS domain protein localisations that we found in the spatio-temporal localisation analyses in Chapter 3. Additionally, we demonstrate that epidermis-expressed GFP-tagged AG is able to move from the epidermis to the subepidermis in the centre of the floral meristem, which provides proof for the suggestions that AG acts non-cell-autonomously in the floral meristem. In these plants we also analyzed the effects of epidermal MADS domain protein expression on the plant phenotype. This showed, among others, that epidermis-expressed AG is able to fully complement its own mutant background, while epidermis-expressed AP3 is not.
In Chapter 6, we explore the mechanisms underlying the behaviour of GFP-tagged SEP3 during petal and stamen development that was observed in the spatio-temporal localisation studies described in Chapter 3. Just prior to the initiation of petal and stamen primordia GFP-tagged SEP3 proteins change their subcellular localisation from predominantly nuclear to more cytoplasmic, and at later stages GFP-tagged SEP3 protein seems to disappear in the middle of the primordia without the loss of SEP3 mRNA expression. These two processes could be regulated at a post-transcriptional level by two mechanisms that are discussed, namely 26s proteasome mediated SEP3 protein degradation and epidermal-oriented intercellular transport of SEP3 proteins. Additionally, we demonstrate that there are no clear indications that the observed GFP-tagged SEP3 behaviour is due to the presence of F-box protein UNUSUAL FLORAL ORGANS (UFO), which regulates petal and stamen development.
In Chapter 7, this thesis finishes with some concluding remarks on in planta imaging of MADS domain transcription factors and the possible mechanisms of MADS domain protein movement in the floral meristem. Furthermore, we speculate on the importance of MADS domain protein movement in establishing MADS box gene expression patterns and MADS domain protein gradients, and on the need for symplastically isolated domains for proper floral development.

LEDs en energiebesparing bij paprika: onderzoek in de praktijk bij VOF Dingemans
Nederhoff, E.M. ; Boer-Tersteeg, P.M. de; Schapendonk, A.H.C.M. ; Pot, C.S. ; Dueck, T.A. ; Bruins, M.A. ; Uenk, D. ; Steenhuizen, J.W. ; Snel, J.F.H. ; Marcelis, L.F.M. ; Kempkes, F.L.K. ; Sapounas, A. ; Driever, S.M. ; Verkerke, W. ; Warmenhoven, M.G. ; Janssen, H.J.J. - \ 2009
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 285) - 106
teelt onder bescherming - kassen - kunstlicht - licht - lichtgevende dioden - morfologie - plantenmorfologie - lichtsterkte - plantenontwikkeling - paprika - glastuinbouw - led lampen - protected cultivation - greenhouses - artificial light - light - light emitting diodes - morphology - plant morphology - light intensity - plant development - sweet peppers - greenhouse horticulture - led lamps
In een praktijkproef met met LED belichting, zijn stuurlichteffect op paprika (ras Derby) niet onomstotelijk bewezen, want lichtkleur en lichtintensiteit waren gekoppeld. Echter, belichtingen met een laag intensiteit (blauw licht, 20 µmol/m2/s, en rood licht, 46 µmol/m2/s) suggereren wel een aantal stuurlicht effecten. Bij rood licht waar belichting startte voor zonsopgang raakte de planten uit balans. De zetting was goed bij rood licht en slecht bij blauw licht. Halverwege het seizoen waren de planten onder blauw licht langer en hadden een groter bladoppervlak dan onbelichte planten, maar dit zou ook te danken kunnen zijn aan grotere beschikbaarheid van assimilaten onder blauw licht. Op basis van hetzelfde hoeveelheid licht (gram per mol), werd een verglijkbare productie berekend onder rood licht en SONT. Met de juiste gewassturing wordt verondersteld dat potentieel 5-10% meer productie kan worden bereikt door belichting met LEDs in vergelijking met SON-T lampen
Growth and development of true sago palm (Metroxylon sagu Rottbøll) : with special reference to accumulation of starch in the trunk : a study on morphology, genetic variation and ecophysiology, and their implications for cultivation
Schuiling, D.L. - \ 2009
Wageningen University. Promotor(en): Paul Struik. - [S.l.] : S.n. - ISBN 9789085858546 - 259
metroxylon sagu - sago - arecaceae - starch crops - plant development - growth analysis - plant morphology - agronomy - maluku - indonesia - ecophysiology - economic botany - metroxylon sagu - sago - arecaceae - zetmeelgewassen - plantenontwikkeling - groeianalyse - plantenmorfologie - agronomie - molukken - indonesië - ecofysiologie - economische botanie
Keywords: Metroxylon sagu, Arecaceae, starch crops, plant growth and development, plant morphology, inflorescence structure, electron microscopy, phenological scale, genetic variation, plant taxonomy, folk taxonomy, ethnobotany, leaf area, leaf area index, starch accumulation, starch distribution, plant ecophysiology, tropical lowlands, wetlands, traditional processing, estate cultivation, agronomy, Moluccas, Maluku.

True sago palm (Metroxylon sagu Rottbøll) is a stout, clustering palm adapted to swampy tropical lowland conditions. Each axis in a sago palm clump flowers once at the end of its life after having amassed a large amount of starch in its trunk. Man can harvest this starch by felling the trunk, pulverizing the pith and leaching the starch out with water, and use it like other starches for food or non-food purposes. It is a staple food mainly in eastern Indonesia and in Papua New Guinea where it is harvested mostly from semi-managed stands. For establishing sago palm as a full-fledged plantation crop, desirable because of its envisaged large yield potential as a perennial, its niche habitat, and its potential as a raw material provider for bio-ethanol production, the scientific base for establishing the right felling time to harvest the starch needed strengthening.

Between October 1988 and November 1990, 27 sago trunks in the Adult Vegetative (AV) or Generative (G) phase belonging to six varieties were selected from semi wild sago stands in the Moluccas, eastern Indonesia: 23 trunks (4 varieties) on the alluvial coastal plain near Hatusua village, Seram Island, and 4 trunks (2 varieties) on hilly terrain near Siri Sori Serani village, Saparua Island. These trunks were felled, dissected, morphologically described and sampled for the amount and distribution of starch they contained. The leafless parts of the trunks were 4.45 to 19.65 m long, had a mean starch density of 4.6 to 254 kg/m3 and contained five to 777 kg of starch (maximum found in a whole trunk: 819 kg).

To link starch content to age, the ages of the sampled trunks had to be estimated. To enable age estimation by counting leaf scars on the trunk, the leaf unfolding rate of 36 AV-phase palms around Hatusua (31 palms) and Siri-Sori Serani (5 palms) was monitored for varying periods between 1989 and 1992. Probably due to large variation in habitat and genetic make up, this rate varied from 2 to 14 leaves per year (mean 7.85), rendering number of leaf scars unfit as accurate age estimator. Also trunk height proved unfit for this purpose. From monitoring 5 G-phase palms, the G-phase could be subdivided into 3 sub-phases (G1, G2, G3), recognizable from the ground by the phased development of the successive orders of inflorescence branches. By combining gathered morphological and monitoring data, a phenological scale of a model palm was composed consisting of two parallel timelines of hidden and outwardly visible events: two years after the start of the Establishment (E) phase, the first AV-phase leaf is initiated in the apical growing point, to unfold only 2.5 years later; the initiation of the first AV-phase tissues is followed 12.5 to 14.5 years later by the initiation of the first G-phase tissues, followed 4 to 5.5 years later by the shedding of fruits, and finally by a 2- to 5-year Recycling phase (name proposed here) in which the axis decays and collapses. This scale, which accounts for the large time gap between initiation of trunk parts and their becoming visible, may help to correctly time cultural measures. The 27 sampled trunks could tentatively be ranked according to physiological age into 4 AV phase classes and 9 G phase classes.

Since the examined palms belonged to 6 different local varieties, their relative rareness or commonness had to be established to assess the validity of the findings. Based on literature and on interviews with informants, an overview of locally recognised sago palm varieties is presented. The number of unique variety names in 32 localities in Indonesia and Papua New Guinea totalled 325, ranging from 2 (spined vs unspined only) to 34 per locality. On the basis of this survey, the Hatusua varieties were considered average. The nomenclatural category folk variety (fovar, fv.) is proposed to unambiguously name local varieties by adding to the variety name an indication of the location where, and (if known) the ethnic/linguistic group by which that name is used.


Leaf area estimation methods were devised to enable investigation of the relationship between leaf area and starch content. In the AV-phase the Total leaf area (TLA) of a sago palm axis ranged from 200 m2 to 325 m2, one axis having an exceptional TLA of 388 m2. The TLA in the G-phase before fruiting mostly remained within the same range, possibly exceeding it for a short period early in that stage. The Leaf area index (LAI) of an individual axis showed an upward trend from 1 - 1.5 in the E-phase to 1.25 - 1.75 in the AV-phase, to more than 2 in the early G-phase, followed by a decrease to about 1.5 again in the late G-phase before fruiting. No fruiting palms were available for analysis. The TLA and LAI of a single trunk could not be linked to the mean starch density of its pith, nor to the total amount of starch the pith contained.
Generally, starch density in the trunk first increased with height above ground level, reached a maximum about half-way to two-thirds up the leafless part of the trunk, and then sharply dropped towards the top of the trunk. From the late AV phase onward the maximum starch density ranged from 238 to 284 kg/m3. The four trunks with the highest maximum starch densities, all closely around 280 kg/m3, belonged to three different varieties, suggesting that 280 kg/m3 may be considered the maximum starch storage capacity in the pith of any variety.
The starch distribution pattern in the leafless part of the trunk showed a tendency to evolve with age from two tailed (density gradually increasing from base, gradually decreasing towards top) to one tailed (density gradually increasing from base, sharply decreasing towards top). The differences in distribution pattern found strongly suggested that there must be other factors besides age and development phase affecting starch accumulation. Attempts to determine the effect of palm variety and of the environment mostly failed.

Potential yield of a model palm based on the maximum starch density of 280 kg/m3 was estimated at 840 kg of dry starch. That this amount is much higher than generally found may partly be due to poor recovery ratios, as the results of a traditionally processed trunk demonstrated: only 47% of the starch in the processed trunk part was recovered, and if the unharvested starch present in the traditionally discarded basal and top part of the trunk is taken into account, recovery drops to 44%.

In an attempt to establish the point in time at which a sago palm starts to be a nett consumer of its own starch, the course of the energy producing and consuming capacity of an axis during its life time was modelled based on the assumption that by the end of the AV-phase the existing TLA of the axis produces just the amount of energy needed to maintain existing biomass, to keep up the normal regular growth, and to fill new trunk with starch. Using this model, assimilate requirements for building and maintaining the inflorescence and the fruits could not be met by the production capacity of the leaves plus the starch reserves in the trunk. For this modelling approach to succeed in predicting the turning point from nett production to nett consumption of starch by a sago palm axis, additional data on chemical composition of its parts and on assimilation rate are needed.

Lack of precise data on the age of the sampled trunks and lack of uniformity of their genetic make up and growing conditions made it impossible to arrive at the sought-after detailed timetable of the evolution of trunk starch accumulation and depletion to base the right felling time of a sago palm on. The high starch density found in the trunk of a palm with half-grown fruits indicated that depletion of starch reserves by the palm itself may set in much later than generally assumed.
Once the course of starch accumulation in time in a single axis is unravelled, the next research question should be how this adds up in a clump - the actual production unit in a plantation - with axes of different age. Timing felling in such a situation should be aimed at maintaining a maximum starch accumulation rate for the plantation as a whole rather than at harvesting a maximum amount of starch per trunk.

Data sheets of each palm examined containing all primary and some secondary data, and including photographs, are appended in digital form.


Functional-structural plant modelling in crop production
Vos, J. ; Marcelis, L.F.M. ; Visser, P.H.B. de; Struik, P.C. ; Evers, J.B. - \ 2007
Dordrecht : Springer (Wageningen UR Frontis series vol. 22) - ISBN 9781402060335 - 269
gewasproductie - modellen - plantenfysiologie - plantenmorfologie - meting - planten - gewassen - concurrentie tussen planten - planteninteractie - crop production - models - plant physiology - plant morphology - measurement - plants - crops - plant competition - plant interaction
Functional-structural plant models (FSPMs) describe in quantitative terms the development over time of the three-dimensional (3D) structure of plants as governed by physiological processes and affected by environmental factors. FSPMs are particularly suited to analyse problems in which the spatial structure of the plant or its canopy is an essential factor to explain, e.g., plant competition (intra-plant, inter-plant, inter-species) and the effects of plant configuration and plant manipulation (e.g., pruning and harvesting) on yield and produce quality. This book describes the philosophy of functional-structural plant modelling and several tools for making FSPMs; it outlines methods for measuring essential parameters, including those pertaining to plant structure.
Lianas and trees in tropical forests in south China
Cai, Z.Q. - \ 2007
Wageningen University. Promotor(en): Frans Bongers, co-promotor(en): K.F. Cao. - [S.l.] : S.n. - ISBN 9789085046530 - 162
klimplanten - bosbomen - bomen - tropische bossen - biodiversiteit - plantenecologie - plantenmorfologie - china - ecofysiologie - climbing plants - forest trees - trees - tropical forests - biodiversity - plant ecology - plant morphology - china - ecophysiology
A European reference collection of rose varieties : final report
Vosman, B. ; Barendrecht, C.J. ; Esselink, D. ; Jones, H. ; Scott, E. ; Spellerberg, B. ; Tams, S. - \ 2006
Wageningen : Plant Research International - 59
rozen - rosa - cultivars - rassen (planten) - databanken - moleculaire biologie - foto's - gegevens verzamelen - plantenmorfologie - gegevensbeheer - roses - rosa - cultivars - varieties - databases - molecular biology - photographs - data collection - plant morphology - data management
An integrated pilot database was constructed containing administrative, morphological and molecular data as well as pictures of each variety. In spite of some encountered difficulties, it was demonstrated that two laboratories can produce substantially equivalent data and that the molecular data produced is useful as a tool for managing reference collections, prescreening and quality assurance
Contribution to the biosystematics of Celtis L. (Celtidaceae) with special emphasis on the African species
Sattarian, A. - \ 2006
Wageningen University. Promotor(en): Jos van der Maesen, co-promotor(en): Freek Bakker. - [S.l. ] : S.n. - ISBN 9085044456 - 142
celtis - ulmaceae - biosystematiek - soorten - taxonomie - plantenmorfologie - fylogenie - taxonomische revisies - biologische naamgeving - moleculaire taxonomie - afrika - celtis - ulmaceae - biosystematics - species - taxonomy - plant morphology - phylogeny - taxonomic revisions - biological nomenclature - molecular taxonomy - africa
Tillering in spring wheat : a 3D virtual plant modelling study
Evers, J.B. - \ 2006
Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Jan Vos; B. Andrieu. - Wageningen : s.n. - ISBN 9085043778 - 159
triticum aestivum - tarwe - plantenontwikkeling - uitstoeling - plantenmorfologie - modellen - licht - verrood licht - lichtrelaties - optische eigenschappen - bladoppervlakte-index - grondbedekking - triticum aestivum - wheat - plant development - tillering - plant morphology - models - light - far red light - light relations - optical properties - leaf area index - ground cover - cum laude
cum laude graduation (with distinction)
Teelthandleiding vezelvlas : morfologie
Paauw, J.G.M. - \ 2005
Kennisakker.nl 2005 (2005)15 april.
teelt - linum usitatissimum - vlas - plantenmorfologie - plantenanatomie - plantenfysiologie - vezelgewassen - akkerbouw - teelthandleidingen - cultivation - flax - plant morphology - plant anatomy - plant physiology - fibre plants - arable farming - cultivation manuals
In deze teelthandleiding wordt ingegaan op de kieming, vlasstengel, vertakking, de bloem, zaadbollen, zaad, afrijping en de vezel- en bladvorming bij vezelvlas.
Manipulating transplant morphology to advance post-transplant growth and yield in strawberry
Reekie, J.Y. - \ 2005
Wageningen University. Promotor(en): Paul Struik. - Wageningen : S.n. - ISBN 9085042615 - 126
fragaria ananassa - aardbeien - plantenmorfologie - verplanten - maaien - wortel spruit ratio - fragaria ananassa - strawberries - plant morphology - transplanting - mowing - root shoot ratio
Molecular analysis of plant architecture in Arabidopsis thaliana using activation tagging.
Chalfun Junior, A. - \ 2004
Wageningen University. Promotor(en): Maarten Koornneef; Gerco Angenent. - Wageningen : S.n. - ISBN 9085040361 - 144
arabidopsis thaliana - transposons - dna - mutanten - plantenontwikkeling - plantenmorfologie - moleculaire genetica - genexpressie - arabidopsis thaliana - transposable elements - dna - mutants - plant development - plant morphology - molecular genetics - gene expression
From signal to form: Nod factor as a morhogenetic signal molecule to induce symbiotic responses in legume root hairs
Esseling, J.J. - \ 2004
Wageningen University. Promotor(en): Anne Mie Emons. - [S.l.] : S.n. - ISBN 9085040558 - 152
fabaceae - peulgewassen - medicago truncatula - rhizobium - wortelharen - plantenmorfologie - celskelet - symbiose - stikstof - knobbelvorming - signaaltransductie - fabaceae - legumes - medicago truncatula - rhizobium - root hairs - plant morphology - cytoskeleton - symbiosis - nitrogen - nodulation - signal transduction
Teelthandleiding consumptieaardappelen : morfologie (bouw) van de aardappelplant
Veerman, A. - \ 2003
Kennisakker.nl 2003 (2003)15 sept.
solanum tuberosum - aardappelen - landbouwplantenteelt - teeltsystemen - plantkunde - plantenmorfologie - teelthandleidingen - potatoes - crop husbandry - cropping systems - botany - plant morphology - cultivation manuals
De aardappel maakt, evenals tomaat, aubergine, tabak, Spaanse peper en petunia, deel uit van de Solanaceae-familie. De geslachtsnaam waaronder de aardappel thuishoort, is Solanum. Tot dit geslacht behoren ook tomaat en bitterzoet. De volledige soortnaam van de cultuuraardappel is Solanum tuberosum L. De aardappelplant bestaat uit stengels, wortels en knollen
Uitgebreid sortiment kattekruid in kaart gebracht
Hoffman, M.H.A. - \ 2003
Tuin en Landschap 25 (2003)10. - ISSN 0165-3350 - p. 18 - 21.
nepeta - rassen (planten) - cultivars - rassenproeven - plantenveredeling - gebruikswaarde - ornamentele waarde - bloemen - bloei - overblijvende planten - tuinplanten - plantenmorfologie - nomenclatuur - taxonomie - biologische naamgeving - inspectie - evaluatie - sierplanten - bloeiende planten - varieties - variety trials - plant breeding - use value - ornamental value - flowers - flowering - perennials - bedding plants - plant morphology - nomenclature - taxonomy - biological nomenclature - inspection - evaluation - ornamental plants - flowering plants
PPO heeft van 1997 tot 2002 een groot sortiment Nepeta beoordeeld, d.w.z. het volledige Nederlandse handelssortiment aangevuld met nieuwe cultivars, een aantal botanische soorten, en nog onbenoemde selecties uit het veredelingsonderzoek. De planten zijn gekeurd door de KVBC en de Vereniging van Vasteplantenkwekers. In een tabel de uitslag van de sterrenkeuring van de KVBC en de belangrijkste morfologische en gebruikswaarde-kenmerken. Ook worden voorstellen gedaan voor verbeteringen in de naamgeving
Studies in Begoniaceae: VII
Wilde, J.J.F.E. de - \ 2002
Leiden : Backhuys (Wageningen University papers 2001-2) - 271
begoniaceae - begonia - taxonomische revisies - taxonomie - voortplanting - geografische verdeling - plantenecologie - identificatie - determinatietabellen - plantenmorfologie - nieuwe soorten - gabon - kameroen - taxonomic revisions - taxonomy - reproduction - geographical distribution - plant ecology - identification - keys - plant morphology - new species - cameroon
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