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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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Phylogenetworks : exploring reticulate evolution and its consequences for phylogenetic reconstruction
    Vriesendorp, B. - \ 2007
    Wageningen University. Promotor(en): Marc Sosef, co-promotor(en): Freek Bakker; Ronald van den Berg. - [S.l.] : S.n. - ISBN 9789085047032 - 180
    fylogenetica - evolutie - taxonomie - hybridisatie - bedektzadigen - terminologie - phylogenetics - evolution - taxonomy - hybridization - angiosperms - terminology
    Minerals are essential for humans, plants and animals and have an important micronutrient role in physiological and metabolic processes of plants. Next to this essential role of minerals, they can also be very toxic when available to the plant in elevated amounts. Plants therefore need to keep very tight control over the intracellular mineral concentrations in a process called metal homeostasis. Although the metal homeostasis mechanisms are supposed to be universal within plants, there are plant species that can tolerate and even accumulate large amounts of metals without any sign of toxicity. Thlaspi caerulescens J. & C. Presl (Brassicaceae), a close relative of the plant reference species Arabidopsis thaliana (Arabidopsis), is one of these natural metal hyperaccumulator species. The overall aim of this project is to unravel the molecular genetic mechanism of heavy metal tolerance and hyperaccumulation of the metal hyperaccumulating plant species T. caerulescens. To achieve this goal heterologous transcript profiling experiments were performed, which involved comparative microarray hybridization experiments of the hyperaccumulator T. caerulescens and Arabidopsis. Arabidopsis is used as the reference species for heterologous transcript profiling because of the availability of genetic resources and the complete genome sequence. The micronutrient zinc has an essential role in physiological and metabolic processes in plants as a cofactor or structural element. Thlaspi caerulescens can accumulate up to 3% of zinc on a dry weight basis without any sign of toxicity. The question postulated here is if this has drastic effects on the zinc homeostasis mechanism. We examined in detail the transcription profiles of roots of Arabidopsis and T. caerulescens plants grown under deficient, sufficient and excess supply of zinc (Chapter 2). A total of 608 genes were detected in Arabidopsis and 352 in T. caerulescens that responded transcriptionally to changes in zinc supply. Only 14% of these genes were also zinc-responsive in Arabidopsis. When comparing Arabidopsis and T. caerulescens at comparable zinc exposures, over 2200 genes were significantly differentially expressed. While a large fraction of these genes are of yet unknown function, many genes with a different expression between Arabidopsis and T. caerulescens appear to function in metal homeostasis, in abiotic stress response and in lignin biosynthesis. The high expression of lignin biosynthesis genes corresponds to the deposition of lignin in the endodermis. Contrary to Arabidopsis roots, which have one endodermal cell layer, we found there are two endodermal layers in T. caerulescens roots. This extra physical barrier could enhance the control of metal fluxes in the plant, in addition to the higher expression of metal transporters in the root. Cadmium is a widespread, naturally occurring non-essential element that is toxic for plants in higher concentrations. In chapter 3 we compare between and within species transcript profiles of Arabidopsis and T. caerulescens roots exposed to cadmium, with the aim to establish which genes are most likely to be relevant for the tolerance to cadmium exposure of T. caerulescens. The comparative transcriptional analysis of the cadmium response of roots of the T. caerulescens and Arabidopsis emphasizes the role of genes involved in lignin-, glutathione- and sulfate metabolism. Furthermore two transcription factors, MYB72 and bHLH100, with an altered expression after exposure to cadmium, are studied for their involvement in metal homeostasis. Analysis of a myb72 knock-out mutant showed enhanced sensitivity to excess zinc or iron deficiency. Rather than controlling Cd tolerance, this gene appears to be involved in iron homeostasis, affecting the response to Cd indirectly. Arabidopsis transformants overexpressing the transcription factor bHLH100 showed enhanced zinc and nickel tolerance, and although the exact role of this gene still needs to be resolved, the genes appears to have a role in metal homeostasis in Arabidopsis. T. caerulescens accessions exhibit distinct metal accumulation, translocation and tolerance characteristics. T. caerulescens accession Ganges can accumulate high amounts of cadmium and is extremely tolerant to cadmium, whereas the La Calamine accession is also tolerant to cadmium but accumulates much less cadmium compared to Ganges. The transcription profiles of leaves and roots of T. caerulescens accessions Ganges and La Calamine plants grown with and without cadmium were examined using the Qiagen-Operon Arabidopsis Genome Array and results are described in chapter 4. A total of 161 genes were differentially expressed between the two T. caerulescens accessions in response to changes in cadmium supply and 38 genes were differentially expressed in T. caerulescens accession Ganges leaves in response to cadmium. The comparative transcriptional analysis emphasizes that there are just minor differences between the two accessions but the genes which are differentially expressed could play an important role in the hyperaccumulation of cadmium in Ganges. The microarray data suggest that especially genes involved in cell wall modification and stress response relate to the major difference between the two accessions in cadmium hyperaccumulation. Plants have evolved a complex network of homeostatic mechanisms that serve to control the uptake, accumulation, trafficking and detoxification of metals. One potential mechanism for heavy metal detoxification in plants is the chelation of metal ions to ligands like organic acids, amino acids, peptides and polypeptides. This mechanism is important for the distribution of metal ions by keeping metal ions mobile within the plant. In plants metals are often found to be chelated to nicotianamine. Nicotianamine is formed by trimerization of S-adenosylmethionine, which is catalyzed by the enzyme nicotianamine synthase. Arabidopsis contains four nicotianamine synthase (NAS) genes. Also in T. caerulescens four full-length cDNAs encoding nicotianamine synthase members were identified (Chapter 5). The four genes were named TcNAS1-TcNAS4, analogous to the corresponding closest homologue in Arabidopsis. Arabidopsis plants over-expressing TcNAS1, TcNAS2, TcNAS3 or TcNAS4 that were tested for their response to growth on media with different zinc, iron, nickel or cadmium supply, provided evidence that the Thlaspi genes all have a genuine NAS function because they complement the NAS deficiency in specific triple knock-out Arabidopsis mutants. Evidence for a functional role in metal homeostasis was sought in studying the Arabidopsis single, double, triple and a quadruple nicotianamine synthase T-DNA insertion mutants. The combination of null mutations in three or four AtNAS genes, results in a severe phenotype that includes interveinal chlorosis and altered metal concentrations in leaves, roots and seeds. Arabidopsis transformants overexpressing TcNAS3 or TcNAS4 showed enhanced zinc and nickel tolerance compared to wild type plants. The research described in this thesis does contribute to a better understanding of heavy metal hyperaccumulation in T. caerulescens and it can be concluded that it seems unlikely that altered regulation and overexpression of single genes will be sufficient to convert metal nonaccumulators into hyperaccumulators. However, the possibility that overexpression of one or two key regulatory loci have this effect remains.
    Description of Pratylenchus dunensis sp. n. (Nematoda: Pratylenchidae), a root-lesion nematode associated with the dune grass Ammophila arenaria (L.) Link
    Peña, E. de la; Moens, M. ; Aelst, A.C. van; Karssen, G. - \ 2006
    Nematology 8 (2006)1. - ISSN 1388-5545 - p. 79 - 88.
    dutch coastal foredunes - molecular characterization - knot nematode - competition - descriptions - morphology - morphometrics - new species - plant pests - ribosomal DNA - wild relatives - Ammophila arenaria - Elymus farctus - Pratylenchus - Ammophila - Poaceae - Cyperales - monocotyledons - angiosperms - Spermatophyta - plants - eukaryotes - Elymus - invertebrates - animals - Pratylenchidae - nucleotide sequences - plant parasitic nematodes - nematoda - restriction fragment length polymorphism - intergenic DNA - taxonomy - beschrijvingen - morfologie - morfometrie - nieuwe soorten - plantenplagen - ribosomaal DNA - wilde verwanten - Ammophila arenaria - Elymus farctus - Pratylenchus - Ammophila - Poaceae - Cyperales - eenzaadlobbigen - bedektzadigen - Spermatophyta - planten - eukaryoten - Elymus - ongewervelde dieren - dieren - Pratylenchidae - nucleotidenvolgordes - plantenparasitaire nematoden - Nematoda - restrictiefragmentlengtepolymorfisme - intergeen DNA - taxonomie
    A root-lesion nematode, Pratylenchus dunensis sp. n., is described and illustrated from Ammophila arenaria (L.) Link, a grass occurring abundantly in coastal dunes of Atlantic Europe. The new species is characterised by medium sized (454-579 ¿ m) slender, vermiform, females and males having two lip annuli (sometimes three to four; incomplete incisures only visible with scanning electron microscopy), medium to robust stylet (ca 16 ¿ m) with robust stylet knobs slightly set off, long pharyngeal glands (ca 42 ¿ m), lateral field with four parallel, non-equidistant, lines, the middle ridge being narrower than the outer ones, lateral field with partial areolation and lines converging posterior to the phasmid which is located between the two inner lines of the lateral field in the posterior half of the tail, round spermatheca filled with round sperm, vulva at 78% of total body length and with protruding vulval lips, posterior uterine sac relatively short (ca 19 ¿ m), cylindrical tail (ca 33 ¿ m) narrowing in the posterior third with smooth tail tip and with conspicuous hyaline part (ca 2 ¿ m). Males occur abundantly and present similar characteristics except for smaller dimensions for all morphological characters, but the head region is more truncated in outline than the female, spicule length is ca 15 ¿ m and testis length is ca 195 ¿ m. Nucleotide sequences of the rDNA expansion region D2D3 differed from the morphologically similar species P. penetrans and P. brzeskii that also occur in coastal dunes. These differences are supported by PCR-RFLP of the ITS-rDNA. Pratylenchus dunensis sp. n. was also found parasitising roots of Elymus farctus Viv.
    Morphological, molecular, and differential-host characterization of Meloidogyne floridensis n. sp (Nematoda : Meloidogynidae), a root-knot nematode parasitizing peach in Florida
    Handoo, Z.A. ; Nyczepir, A.P. ; Esmenjaud, D. ; Beek, J.G. van; Castagnone-Sereno, P. ; Carta, L.K. ; Skantar, A.M. ; Higgins, J.A. - \ 2004
    Journal of Nematology 36 (2004)1. - ISSN 0022-300X - p. 20 - 35.
    myrobalan plum - enzyme phenotypes - perineal patterns - prunus-cerasifera - resistance - heteroderidae - rootstock - identification - polymorphism - javanica - descriptions - host range - hosts - morphology - morphotaxonomy - new species - parthenogenesis - peaches - plant pests - Meloidogyne - Meloidogyne arenaria - Meloidogyne chitwoodi - Meloidogyne fallax - Meloidogyne floridensis - Meloidogyne graminicola - Meloidogyne hapla - Meloidogyne incognita - Meloidogyne javanica - Prunus persica - Florida - Meloidogynidae - invertebrates - animals - eukaryotes - Prunus - Rosaceae - Rosales - dicotyledons - angiosperms - Spermatophyta - plants - Gulf States of USA - Southern States of USA - APEC countries - Developed Countries - North America - America - OECD Countries - South Atlantic States of USA - Southeastern States of USA - animal anatomy - nucleotide sequences - plant parasitic nematodes - nematoda - host parasite relationships - random amplified polymorphic DNA - taxonomy - USA - beschrijvingen - gastheerreeks - gastheren (dieren, mensen, planten) - morfologie - morfotaxonomie - nieuwe soorten - parthenogenese - perziken - plantenplagen - Meloidogyne - Meloidogyne arenaria - Meloidogyne chitwoodi - Meloidogyne fallax - Meloidogyne floridensis - Meloidogyne graminicola - Meloidogyne hapla - Meloidogyne incognita - Meloidogyne javanica - Prunus persica - Florida - Meloidogynidae - ongewervelde dieren - dieren - eukaryoten - Prunus - Rosaceae - Rosales - tweezaadlobbigen - bedektzadigen - Spermatophyta - planten - golfstaten van de VS - zuidelijke staten van de VS - APEC-landen - ontwikkelde landen - Noord-Amerika - Amerika - OESO-landen - zuid-Atlantische staten van de VS - zuidoostelijke staten van de VS - dieranatomie - nucleotidenvolgordes - plantenparasitaire nematoden - Nematoda - gastheer parasiet relaties - random amplified polymorphic DNA - taxonomie - VS
    A root-knot nematode, Meloidogyne floridensis n. sp., is described and illustrated from peach originally collected from Gainesville, Florida. This new species resembles M. incognita, M. christiei, M. graminicola, and M. hispanica, but with LM and SEM observations it differs from these species either by the body length, shape of head, tail and tail terminus of second-stage juveniles, body length and shape of spicules in males, and its distinctive female perineal pattern. This pattern has a high to narrowly rounded arch with coarsely broken and network-like striae in and around anal area, faint lateral lines interrupting transverse striae, a sunken vulva and anus, and large distinct phasmids. Molecular data from ribosomal IGS illustrate that M. floridensis n. sp. is different from the mitotic species M. arenaria, M. incognita, and M. javanica. Data from RAPDs confirm it and suggest that this new species lies in an intermediate phylogenetic position between the previous species and the meiotic species M. hapla, M. fallax, and M. chitwoodi. Differential host tests based on annual crops and on Prunus accessions are reported.
    Ovules, megagametophytes and embryos. Ultrastructural studies after cryofixation
    Thijssen, M.H. - \ 2003
    Wageningen University. Promotor(en): J.L. van Went, co-promotor(en): Anne Mie Emons. - [S.l.] : S.n. - ISBN 9789058088826
    planten - bedektzadigen - brassica - petunia - onbevruchte eitjes - cryopreservering - plantenembryo's - celultrastructuur - biologische technieken - plants - angiosperms - brassica - petunia - ovules - cryopreservation - plant embryos - cell ultrastructure - biological techniques
    Plant Resources of South-East Asia No. 11. Auxiliary plants
    Jansen, P.C.M. ; Oyen, L.P.A. ; Maesen, L.J.G. van der - \ 1997
    Leiden : Backhuys Publishers (Plant Resources of South-East Asia 11) - ISBN 9789073348660 - 389
    wilde planten - bedektzadigen - bosbouw - bomen - beplantingen - zuidoost-azië - dekgewassen - bosproducten anders dan hout - economische botanie - wild plants - angiosperms - forestry - trees - plantations - south east asia - cover crops - non-wood forest products - economic botany
    Legumes traditionnels du Cameroun, une etude agro-botanique
    Stevels, J.M.C. - \ 1990
    Agricultural University. Promotor(en): L.J.G. van der Maesen; M. Flach, co-promotor(en): F.J. Breteler. - Wageningen : Agricultural University - ISBN 9789067541510 - 262
    bedektzadigen - wilde planten - tuinieren - groenteteelt - sierplanten - kameroen - plantkunde - economische botanie - angiosperms - wild plants - gardening - vegetable growing - ornamental plants - cameroon - botany - economic botany

    Cameroon has a remarkable abundance of vegetable species. A great variety of local and introduced vegetable crops are grown and together with a significant number of wild and semi-wild plants, occasionally cultivated, form a valuable complementary food in the daily diet.

    Primarily the aim of this study is to present an inventory of traditional vegetable species in Cameroon, indicating their importance in local agriculture, their significance as food and their nutritional value. The second objective is a taxonomical study of these vegetable crops, in order to expose, and where feasible eliminate, the existing widespread confusion in their scientific nomenclature. Botanical descriptions and practical differential keys, based on those parts of the plants that are actually used, are provided. This study deals with 67 traditional vegetables, 20 species of which are discussed in greater detail. The materials and data were gathered mainly in Cameroon during the period 1975 - 1979, and subsequently elaborated upon at the Department of Plant Taxonomy of the Agricultural University, Wageningen, The Netherlands.

    Chapter I contains a general introduction. The working plan (chapter 2) clarifies the selection of the 20 primary species (paragraph 2.1). Further detailed information is supplied regarding the materials used and the applied methods of investigation (paragraph 2.2).

    Chapter 3 presents the five agro-ecological regions into which Cameroon can be divided (paragraph 3. 1). A review is given of the physical and biological environment (paragraph 3.2) and of the agriculture and animal husbandry (paragraph 3.3). Various aspects pertaining to vegetables are discussed, such as the different types of vegetable crops (paragraph 3.4. 1), local and introduced vegetables (paragraph 3.4.2), the inventory of the vegetables in the different agro- ecological regions (paragraph 3.4.3) and a classification of wild and/or cultivated species (paragraph 3.4.4). Finally the various types of vegetable production are dealt with (paragraph 3.5).

    Chapter 4 is based on nutritional research and surveys which have been carried out in Cameroon since 1953. The first part is devoted to a survey of food and nutrition in the different agro-ecological regions (paragraph 4. 1). In the second part an account is given of the preparation and utilisation of vegetables including their nutritional value (paragraph 4.2).

    Chapter 5 deals with the botanical study of the vegetable species. Differential keys to groups of species (paragraph 5. 1. 1) and to individual species (paragraph 5.1.2), based on characteristics of the edible product, are supplied. In the next paragraph (5.2) all 67 species are arranged in alphabetical order, primarily in family order and subsequently according to the genera and species. This paragraph also provides concise information concerning the 47 secondary species.

    The 20 primary species are considered in a final paragraph (5.3), also in alphabetical order.
    The format of the text in the paragraphs 5.2 and 5.3 is essentially similar for each species. In paragraph 5.2 the author and the original publication of the species are cited, along with the current synonyms, pertinent literature, vernacular names, the occurrence in each of the five agro-ecological regions, a concise botanical description, a few relevant notes, representative herbarium specimens from Cameroon and finally the applicability as a vegetable. Furthermore paragraph 5.3 provides an etymological explanation of the scientific name and the typification, while synonymy, literature, geographic distribution and botanical description are discussed at length. Notes in this paragraph elaborate the typification. Any other relevant questions are subsequently dealt with, such as the recurring confusion with other species of the same genus, infraspecific variation and the distinction of cultivar-groups or cultivars, some cytogenetic and evolutionary aspects, and the use as a vegetable. Finally all the herbarium material examined from Cameroon is listed.

    Each species is accompanied by a botanical drawing of the edible parts of the plant in paragraph 5.2. Species dealt with in paragraph 5.3 are fully illustrated. In some cases a photograph is added. In conclusion a general bibliography and indices of scientific and vernacular plant names are provided.

    Dictionary of cultivated plants and their regions of diversity : excluding most ornamentals, forest trees and lower plants
    Zeven, A.C. ; Wet, J.M.J. de - \ 1982
    Wageningen : Pudoc - ISBN 9789022007853
    oorsprong - distributie - vestiging - genenbanken - genetische bronnen - germplasm - hulpbronnenbehoud - genetische bronnen van plantensoorten - agronomie - bedektzadigen - wilde planten - flora - plantengeografie - wereld - plantkunde - nieuwe cultuurgewassen - economische botanie - origin - distribution - establishment - gene banks - genetic resources - germplasm - resource conservation - plant genetic resources - agronomy - angiosperms - wild plants - flora - phytogeography - world - botany - new crops - economic botany
    Vleesetende en insectenetende planten
    Anonymous, - \ 1979
    Wageningen : Pudoc (Literatuurlijst / Centrum voor Landbouwpublikaties en Landbouwdocumentatie no. 4317)
    bedektzadigen - bibliografieën - vleesetende planten - insectivore planten - angiosperms - bibliographies - carnivorous plants - insectivorous plants
    Vitality and metabolic properties of binucleate and trinucleate pollen species upon dehiscence
    Hoekstra, F.A. - \ 1979
    Landbouwhogeschool Wageningen. Promotor(en): J. Bruinsma. - Wageningen : Hoekstra - 87
    bedektzadigen - plantenfysiologie - stuifmeel - stuifmeelkieming - openspringen - angiosperms - plant physiology - pollen - pollen germination - dehiscence - cum laude

    Chapter 1

    Effects of various components upon germination in vitro were studied in order to develop an optimal germination medium for Compositae pollen. Equilibration of pollen in humid air, preceding germination, improved the reliability of results considerably.

    Irregular germination ability of pollen samples, originating from different collections, was studied by exposing flowering plants to different climatic conditions. High relative humidity and temperature at dehiscence cause a rapid decrease in pollen vitality. Data for an optimal germination medium and for acquisition of good pollen quality are presented.

    Chapter 2

    The respiration and vitality of ungerminated bi- and trinucleate pollen were studied in order to determine the influence of relative humidity and temperature on metabolic activity. The gas exchange, gerniination capacity and staining with tetrazolium bromide were followed under standardized conditions.

    A constant respiration rate occurred under conditions of high relative humidity (97 %). Per mg pollen, the trinucleate grains of Compositae and Gramineae respired 2 to 3 times as intense as 6 species of binucleate grains. Per unit of pollen protein the differences were even larger. In contrast to binucleate pollen, the longevity of trinucleate pollen was very short and the ability to germinate was lost twice as fast as the respiration capacity. This limits the use of tetrazolium bromide as an indicator of viability.

    At reduced relative humidities respiration was strongly restricted, but the longevity of bi- and trinucleate pollen considerably increased.

    Pollen of Gramineae, however, was very sensitive to changes in relative humidity; short exposure to low relative humidity decreased both the vitality and the capacity to respire.

    Chapter 3

    Bi- and trinucleate pollen generally differ in the extent of their mitochondrial development at anther dehiscence and in the rate of their attainment of maximum-phosphorylative capacity during germination in vitro, as judged from experiments with representatives of both groups.

    The typically trinucleate pollen of Aster tripolium L. immediately respired at a high rate, maintaining a high energy charge. Mitochondria attained maximum electron-transducing capacity within 2 min of incubation, while tube growth started within 3 min. In contrast, the binucleate pollen of Typha latifolia L. only gradually reached a relatively low rate of respiration, concomitant with a temporary decrease in energy charge, upon immersion in the germination medium. Development of the mitochondrial, electron-transducing system occurred in about 75 min, after which the first pollen tubes emerged. Starting from a poor differentiation, mitochondria became increasingly normal in appearance as germination proceeded.

    The binucleate pollen of Nicotiana alata Link et Otto and Tradescantia paludosa Anders. et Woods. showed intermediate characteristics: Nicotiana resembled Typha but mitochondria developed at a higher rate; Tradescantia germinated more rapidly and resembled the trinucleate pollen of Aster.

    Inhibitors of mitochondrial or cytoplasmic protein synthesis failed to affect the development of the mitochondrial, respiratory capacities during pollen germination. It is concluded that the duration of the lag period is determined by the level and rate of mitochondrial development and not by the division of the generative cell.

    Chapter 4

    The equal rates of water vapour absorption by both bi- and trinucleate pollen indicate that their widely-differing rates of respiration have an intrinsic, biochemical basis. This was investigated with various metabolic inhibitors that were previously introduced into dry pollen via anhydrous acetone

    The uncoupler, CCCP, inhibited the O 2 uptake of rapidly respiring pollen and stimulated that of slowly respiring types to similar absolute values, that probably reflect the rates of substrate transport across the mitochondrial membranes.

    The extent of inhibition of the O 2 uptake by oligomycin, DCCD, antimycin A, and SHAM, alone and in combinations, indicates that hardly any oxidative phosphorylation and anabolic activities occur in slowly respiring, binucleate pollen species, having low-developed mitochondria and high EC values. The presence of the alternative pathway was insignificant.

    In other binucleate pollen species, characterized by recognizable mitochondria and low EC values, a limited ATP synthesis was established. The low EC values point to imbalance between phosphorylative and anabolic activities.

    In rapidly respiring, trinucleate pollen, containing well- developed mitochondria, a significant activity of the alternative oxidase was found. The EC values were high notwithstanding the large demand for ATP, mounting to 1.7 μmol h -1mg pollen -1.

    In some pollen species, oligomycin highly stimulated the flow of electrons through the cytochrome pathway, which made an estimation of the ATP synthesis impossible.

    Chapter 5

    Under humid conditions both bi- and trinucleate pollen species incorporate very low amounts of leucine, 0.4 pmol min -1mg pollen -1on an average. During germination in vitro , however, the two types of pollen greatly differ in their capacity for protein synthesis.

    Binucleate pollen species such as Typha , which are characterized by slow respiration in humid air and prolonged lag periods during germination in vitro , contain large amounts of monoribosomes at dehiscence. Polyribosomes are formed soon after the pollen is wetted in the germination medium and a considerable incorporation of leucine is initiated after 10-15 min.

    More rapidly respiring, binucleate pollen, such as Tradescantia , showing a short lag period, may contain many polysomes at dehiscence already and incorporates leucine within 2 min of incubation.

    On the contrary, rapidly respiring, trinucleate Compositae pollen contains very limited amounts of ribosomal material and never attains any substantial level of incorporation.

    Cycloheximide completely inhibited both protein synthesis and tube emergence and growth in the slowly respiring binucleate pollen species. The more rapidly respiring types are less dependent on protein synthesis, while germination of the phylogenetically advanced, trinucleate Compositae pollen proceeds completely independently.

    It is concluded that the level of phylogenetic advancement of the male gametophyte is characterized by its overall state of metabolic development at dehiscence rather than by the number of its generative cells.

    Contribution a l'etude ethnobotanique des Wagenia de Kisangani, Zaire
    Bokdam, J. ; Droogers, A.F. - \ 1975
    Wageningen : Veenman (Mededelingen Landbouwhogeschool Wageningen 75-19) - 74
    bedektzadigen - oorsprong - distributie - vestiging - etnografie - antropologie - wilde planten - plantkunde - volkscultuur - democratische republiek kongo - nieuwe cultuurgewassen - gebruiken - volkenkunde - economische botanie - angiosperms - origin - distribution - establishment - ethnography - anthropology - wild plants - botany - folk culture - congo democratic republic - new crops - customs - ethnology - economic botany
    Dictionary of cultivated plants and their centres of diversity : excluding ornamentals, forest trees and lower plants
    Zeven, A.C. ; Zhukovsky, P.M. - \ 1975
    Wageningen : Pudoc - ISBN 9789022005491
    oorsprong - distributie - vestiging - agronomie - bedektzadigen - wereld - plantkunde - wilde planten - flora - plantengeografie - nieuwe cultuurgewassen - economische botanie - origin - distribution - establishment - agronomy - angiosperms - world - botany - wild plants - flora - phytogeography - new crops - economic botany
    Bevruchting
    Sneep, J. - \ 1975
    Wageningen : LH, Plantenveredeling - 54
    bevruchting - bestuiving - plantenembryo's - voortplanting - embryozak - bedektzadigen - fertilization - pollination - plant embryos - reproduction - embryo sac - angiosperms
    Tentative determination key to 600 trees, shrubs and climbers from the Ivory Coast, Africa, mainly based on characters of the living bark, besides the rhytidome and the leaf
    Outer, R.W. den - \ 1972
    Wageningen : Veenman (Mededelingen Landbouwhogeschool 72-18,19,20,21) - 4
    planten - identificatie - bedektzadigen - bosbouw - bomen - floëem - schors, bomen - plantenmorfologie - ivoorkust - bladeren - plantenfysiologie - plants - identification - angiosperms - forestry - trees - phloem - bark - plant morphology - cote d'ivoire - leaves - plant physiology
    Enige veldkenmerken van de voornaamste plantenfamilies met boomvormige vertegenwoordigers in Suriname
    Boerboom, J.H.A. - \ 1971
    Wageningen : [s.n.] (Celos rapporten no. 55) - 72
    bedektzadigen - bosbouw - suriname - bomen - angiosperms - forestry - suriname - trees
    Rotylenchulus borealis n.sp. with a key to the species of Rotylenchulus
    Loof, P.A.A. ; Oostenbrink, M. - \ 1962
    Nematologica 7 (1962)1. - ISSN 0028-2596 - p. 83 - 90.
    differentiële diagnose - vruchten - nieuwe combinatie - nieuwe soorten - boomgaarden - wortels - bodem - aardbeien - Fragaria - Nederland - Rosaceae - Rosales - tweezaadlobbigen - bedektzadigen - Spermatophyta - planten - eukaryoten - Benelux - ontwikkelde landen - landen van de Europese Unie - Koninkrijk der Nederlanden - OESO-landen - West-Europa - Europa - Balkan - Zuid-Europa - Middellandse-Zeegebied - Joegoslavië - taxonomie - differential diagnosis - fruits - new combination - new species - orchards - roots - soil - strawberries - Fragaria - Netherlands - Rosaceae - Rosales - dicotyledons - angiosperms - Spermatophyta - plants - eukaryotes - Benelux - Developed Countries - European Union Countries - Kingdom of the Netherlands - OECD Countries - Western Europe - Europe - Balkans - Southern Europe - Mediterranean Region - Yugoslavia - taxonomy
    Rotylenchulus borealis n.sp. is described and illustrated from specimens collected from the roots of grasses near Arnhem, Netherlands. Dimensions of males and of immature and mature females are given. The species occurs in other localities in the Netherlands and has been found in soil around plum, apple and strawberry roots; a single immature female has also been recorded from a potato field in Yugoslavia. Adult females of R. borealis occur predominantly only on the roots of grasses near fruit trees-possibly this is because the soil type of most large Dutch orchards is suitable for the nematode. A key to the 6 described species of Rotylenchulus and a differential diagnosis for R. borealis are given. R. leiperi is cited as a new combination for Leiperotylenchus leiperi Das, 1960. T.D.W.
    Der Transport von Pratylenchiu penetrans (Nematoda) mit Pflanzgut. [English title not available]
    Oostenbrink, M. - \ 1957
    Zeitschrift fuer Pflanzenkrankheiten Pflanzenpathologie und Pflanzenschutz 64 (1957)7/10. - ISSN 0044-3271 - p. 484 - 490.
    parasieten - aardappelen - wortels - bodem - knollen - Pratylenchus - Pratylenchus penetrans - Solanum tuberosum - ongewervelde dieren - dieren - eukaryoten - Pratylenchidae - Solanum - Solanaceae - Solanales - tweezaadlobbigen - bedektzadigen - Spermatophyta - planten - plantenparasitaire nematoden - Nematoda - plantmateriaal - parasites - potatoes - roots - soil - tubers - Pratylenchus - Pratylenchus penetrans - Solanum tuberosum - invertebrates - animals - eukaryotes - Pratylenchidae - Solanum - Solanaceae - Solanales - dicotyledons - angiosperms - Spermatophyta - plants - plant parasitic nematodes - nematoda - planting stock
    Pratylenchus penetrans and P. pratensis were shown not to be parasites of the potato tuber although potato roots can harbour considerable populations. Normally stored tubers from infested fields would not be a source of infestation. Nursery stock of various trees can be a carrier of the eelworms, particularly P. penetrans, but if planted in nematode-free soil the stock produces healthy roots and little, if any, damage is caused. J.B.G.
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