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  • 1.
    Andersson, Lars
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Bostrom, Ullalena
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Forkman, Johannes
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Hakman, Inger
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Liew, Josefine
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Sprouting capacity from intact root systems of Cirsium arvense and Sonchus arvensis decrease in autumn2013In: Weed research (Print), ISSN 0043-1737, E-ISSN 1365-3180, Vol. 53, no 3, p. 183-191Article in journal (Refereed)
    Abstract [en]

    Perennial weeds are often controlled by mechanical means, which aim at stimulating axillary and adventitious buds to sprout. This happens when the apical dominance of the main shoot is removed by defoliation or when the underground system is fragmented. By repeating the measures, the result is a depletion of storage compounds, which weakens the plants and reduces their capacity to grow and reproduce. However, timing is critical. Earlier research has indicated that emergence from fragments of Sonchus arvensis cease during a period in autumn, while the seasonal pattern of sprouting in Cirsium arvense appears to be inconsistent. We studied the emergence pattern of defoliated plants with undisturbed root systems, from late summer to early spring. Potted plants grown outdoors were exhumed at regular intervals, put under forcing conditions for 4weeks, after which shoots above and below soil level were counted and weighed together with the remaining root systems. In both species, the number and weight of emerged shoots decreased during a period in the autumn. In C.arvense, underground shoots were constantly produced during the same period, while fewer underground shoots were present in S.arvensis. For the latter species, apical dominance does not fully explain the effect; thus, endodormancy might be involved. Root weight increased until withering and did not explain the lack of emergence. Our results suggest an impaired sprouting capacity of undisturbed root systems of C.arvense and S.arvensis during SeptemberOctober, which has implications for the timing and method of control of these species.

  • 2. Andersson, Lars
    et al.
    Boström, Ullalena
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Liew, Josefine
    Karlsson, Laila
    Milberg, Per
    Dormancy in reproductive vegetative buds of perennial species dominating the agricultural weed flora in Scandinavia.2008Conference paper (Other academic)
  • 3. Andersson, Lars
    et al.
    Boström, Ullalena
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Liew, Josefine
    Magnuski, Eva
    Milberg, Per
    SPROUTING CAPACITY OF UNDERGROUND LATERAL BUDS OF RHIZOMATEOUS PERENNIAL WEEDS VARY WITH SEASON2010Conference paper (Other academic)
  • 4.
    Andersson, Lars
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Boström, Ullalena
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Liew, Josefine
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Karlsson, Laila
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Milberg, Per
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Spirehvile i rødder og rhizomer i de vigtigste rodukrudtsarter - resultater fra svenske forsøg.2010In: Proceedings Plantekongres 2010, 2010, p. 330-331Conference paper (Other academic)
  • 5.
    Boström, Ullalena
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Andersson, Lars
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Forkman, Johannes
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Hakman, Inger
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Liew, Josefine
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Seasonal variation in sprouting capacity from intact rhizome systems of three perennial weeds.2013In: Weed research (Print), ISSN 0043-1737, E-ISSN 1365-3180, Vol. 53, no 5, p. 387-398Article in journal (Refereed)
    Abstract [en]

    The three rhizomatous perennials Elytrigia repens, Equisetum arvense and Tussilago farfara are all problematic in Scandinavian agriculture, due to their low susceptibility to soil cultivation. While repeated soil tillage is a fundamental part of the integrated control of these species, it is highly energy consuming and inefficient during periods when little sprout regrowth occurs. Substituting cultivation with mowing will reduce the environmental impact and labour costs, but its efficiency will still depend on the capacity of plants to sprout. Therefore, we studied the seasonal pattern in emergence and rhizome biomass allocation from July to April in six populations for each of the species. Plants were grown outdoors in pots buried in soil and exhumed at regular intervals in a two-year experiment. In all three species, biomass allocation to rhizomes continued until late in the autumn. Emergence was severely impaired in E.arvense and T.farfara in September-October, while in E.repens, there was no such reduction in the number of emerged shoots. However, in the latter species, the shoot/rhizome ratio decreased and remained low until the plants had been exposed to a period of low temperatures. The increase in shoot/rhizome ratio for E.repens coincided with the resumed capacity to emerge for E.arvense and T.farfara. These results imply that there is no need to repeat a defoliation of E.arvense and T.farfara, if carried out in September-October. However, removal of the aerial plant parts early in the autumn is important to interrupt the upload of storage compounds to the rhizome systems of all species.

  • 6. Eriksson, T.
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Progress and prospects in tissue culture and in vitro propagation of spruce.1989In: International Symposium on Application of Biotechnological Methods and Recent Accomplishments of Economic Value in Asia, Chulalongkom University, Bangkok, 5-9 November 1989., 1989Conference paper (Refereed)
  • 7. Eriksson, T.
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Progress in tissue culture and in vitro propagation of spruce.1990Conference paper (Refereed)
  • 8. Fowke, Larry C.
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Somatic embryogenesis in conifers1988In: Plant Cell Biotechnology. NATO ASI Series H: CellBiology, Vol. 18, p. 75-80Article, review/survey (Other academic)
  • 9. Gorbatenko, O
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Desiccation-tolerant somatic embryos of Norway spruce (Picea abies) can be produced in liquid cultures and regenerated into plantlets2001In: International journal of plant sciences, Vol. 162 (6), p. 1211-1218Article in journal (Refereed)
  • 10. Gorbatenko, O.
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The effect of Brefeldin A on the Golgi apparatus in Norway spruce cells1995In: Kluwer Academic Publishers. Current Issues in Plant Molecular and Cellular Biology. Proceedings of the VIIIth International Congress on Plant Tissue and Cell Culture, Florence, Italy, 12-17 June, 1994 / [ed] M. Terzi, R. Cella & A. Falavigna, 1995Conference paper (Refereed)
  • 11. Griffiths, G.
    et al.
    Hakman, Inger
    Inst, of Physiological Botany, Univ. of Uppsala.
    Tillberg, E.
    Hellman, M.
    Stymne, S.
    Stobart, K.
    The biosynthesis of triacylglycerols in oil-seeds with a perspective view on the role of plant growth regulators.1988In: Monograph / British Plant Growth Regulator Group, ISSN 0952-6463, no 17, p. 11-33Article in journal (Refereed)
  • 12.
    Hakman, Inger
    Department of Botany, Stockholm University .
    Correction1992In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 84, no 2, p. 318-318Article in journal (Refereed)
  • 13.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Embryology in Norway spruce (Picea abies) - an analysis of the composition of seed storage proteins and deposition of storage reserves during seed development and somatic embryogenesis1993In: Physiologia plantarum, Vol. 87 (2), p. 148-159Article in journal (Refereed)
  • 14.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Embryology in Norway spruce (Picea abies) - immunochemical studies on transport of a seed storage protein1993In: Physiologia plantarum, Vol. 88, no 3, p. 427-433Article in journal (Refereed)
  • 15.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Tissue culture in conifers.1985Report (Other academic)
  • 16.
    Hakman, Inger
    et al.
    Institute of Physiological Botany, University of Uppsala.
    Fowke, L C
    An embryogenic cell-suspension culture of Picea glauca (White spruce)1987In: Plant Cell Reports, ISSN 0721-7714, E-ISSN 1432-203X, Vol. 6, no 1, p. 20-22Article in journal (Refereed)
    Abstract [en]

    A cell suspension culture of Picea glauca (White spruce) which continuously produces somatic embryos has been established. Embryogenic callus derived from cultured zygotic embryos was used to initiate the culture. Numerous embryos at various early stages of development were recognized; they exhibited a meristematic embryonic region and suspensor consisting of elongate, vacuolated cells. The culture also contained clumps of meristematic cells and large irregular — shaped cells. The culture could be readily re-established on solid medium. 

  • 17.
    Hakman, Inger
    et al.
    Institute of Physiological Botany, University of Uppsala.
    Fowke, L C
    Somatic embryogenesis in Picea glauca (White spruce) and Picea mariana (Black spruce)1987In: Canadian Journal of Botany, ISSN 0008-4026, E-ISSN 1480-3305, Vol. 65, no 4, p. 656-659Article in journal (Refereed)
    Abstract [en]

    Embryogenic callus was initiated from immature embryos of Picea glauca (white spruce) and Picea mariana (black spruce) cultured on defined media supplemented with 2,4-dichlorophenoxyacetic acid (1 × 10−5 M), N6-benzyladenine (5 × 10−6 M), and 1% sucrose. Seeds from cones stored at 4 °C for up to 3 months yielded embryogenic callus. Much higher frequencies of embryogenic callus were obtained from white spruce than from black spruce. Embryogenic callus contained loosely organized cells and somatic embryos of various sizes. The embryos consisted of a cluster of tiny dividing cells (embryonic region) with attached large vacuolated cells (suspensor region). Upon subculture of embrogenic callus to media either lacking growth regulators or with reduced concentrations (5 × 10−7 M, 2,4-dichlorophenoxyacetic acid and 5 × 10−6 M N6-benzyladenine) somatic embryos could be stimulated to develop into plantlets. 

  • 18.
    Hakman, Inger
    et al.
    Institute of Physiological Botany, University of Uppsala, Box 540, S-751 21 Uppsala, Sweden.
    Fowke, L C
    Vonarnold, S
    Eriksson, T
    The development of somatic embryos in tissue-cultures initiated from immature embryos of Picea abies (Norway spruce)1985In: Plant Science, ISSN 0168-9452, E-ISSN 1873-2259, Vol. 38, no 1, p. 53-59Article in journal (Refereed)
    Abstract [en]

    Embryos of Picea abies at various developmental stages were cultured on defined media supplemented with 2,4-dichlorophenoxyacetic acid (2,4-D) (10−5 M) and N6-benzyladenine (BA) (5×10−6 M). The immature embryos gave rise to a highly friable and embryogenic callus which could be maintained by subculture and contained polarized and organized structures (somatic embryos) consisting of long highly vacuolated cells at one end (suspensor) and a group of small meristematic cells at the other (embryonal end). These structures closely resembled the early stages of normal zygotic embryogeny. Upon further culture these structures formed a bipolar shoot-root axis with an independent and closed vascular system. In many instances either the shoot or the root meristems failed to differentiate. Embryogenic tissues obtained on agar media could be transferred to liquid media and maintained by subculture for at least 6 months. The development of somatic embryos was observed in the liquid cultures also. 

  • 19.
    Hakman, Inger
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hallberg, Henrik
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Palovaara, Joakim
    University of Kalmar, School of Pure and Applied Natural Sciences.
    The polar auxin transport inhibitor NPA impairs embryo morphology and increases the expression of an auxin efflux facilitator protein PIN during Picea abies somatic embryo development2009In: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 29, no 4, p. 483-496Article in journal (Refereed)
    Abstract [en]

    Auxin and polar auxin transport have been implicated in controlling embryo patterning and development in angiosperms but less is known from the gymnosperms. The aims of this study were to determine at what stages of conifer embryo development auxin and polar auxin transport are the most important for normal development and to analyze the changes in embryos after treatment with the polar auxin inhibitor N-1-naphthylphthalamic acid (NPA). For these studies, somatic embryos of Norway spruce (Picea abies L. Karst) were used. Growth on medium containing NPA leads to the formation of embryos with poor shoot apical meristem (SAM) and fused cotyledons, and to a pin-formed phenotype of the regenerated plantlets. The effect of NPA on embryo morphology was most severe if embryos were transferred to NPA-containing medium immediately before cotyledon initiation and SAM specification. Indole-3-acetic acid (IAA) was identified by immunolocalization in developing embryos. The highest staining intensity was seen in early staged embryos and then decreased as the embryos matured. No clear IAA-maxima was seen, although the apical parts of embryos, particularly the protoderm, and the suspensor cells appear to accumulate more IAA, as reflected by the staining pattern. The NPA treatment also caused expanded procambium and a broader root apical meristem in embryos, and a significant increase in the expression of a PIN1-like gene. Taken together, our results show that, for proper cotyledon initiation, correct auxin transport is needed only during a short period at the transition stage of embryo development, probably involving PIN efflux proteins and that a common mechanism is behind proper cotyledon formation within the species of angiosperms and conifers, despite their cotyledon number which normally differs.

  • 20.
    Hakman, Inger
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Oliviusson, P
    High expression of putative aquaporin genes in cells with transporting and nutritive functions during seed development in Norway spruce (Picea abies)2002In: Journal of experimental botany, Vol. 53 (369), p. 639-649Article in journal (Refereed)
  • 21.
    Hakman, Inger
    et al.
    Institute of Physiological Botany, University of Uppsala.
    Rennie, P
    Fowke, L C
    A light and electron-microscope study of Picea glauca (White spruce) somatic embryos1987In: Protoplasma, ISSN 0033-183X, E-ISSN 1615-6102, Vol. 140, no 2-3, p. 100-109Article in journal (Refereed)
    Abstract [en]

    Somatic embryos in embryogenic callus cultures derived fromimmature zygotic embryos of Picea glauca (White spruce) wereexamined by light and electron microscopy. Somatic embryos consistof an embryonic region of small densely cytoplasmic cells subtendedby a suspensor consisting of long highly vaeuolated cells. Mitoticfigures are frequent in the embryonic cells but are not observed in thesuspensor. Cell divisions in the embryonic region apparently producerows of cells which elongate to form the suspensor. The presence ofabundant polysomes, coated membranes and dictyosomes in thecytoplasm of embryonic and upper suspensor cells suggests rapidgrowth of the embryo. In contrast the basipetal suspensor cellsappear to be senescing. While only a few scattered microfilaments arepresent in the meristematic celIs, the upper suspensor cells containnumerous bundles of longitudinally oriented microfitaments. Thesebundles correspond to actin cables observed in light microscopepreparations stained with rhodamine labelled phalloidin and areoriented parallel to the direction of active streaming in these cells. 

  • 22.
    Hakman, Inger
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Salaj, J.
    Water channel proteins are expressed early during root formation in Norway spruce - in seedlings, lateral and adventitious roots.1997In: Cost 822. 4th Meeting of the Working Group 3., 1997Conference paper (Refereed)
  • 23.
    Hakman, Inger
    et al.
    Dept of Physiological Botany, University of Uppsala.
    Stabel, P
    Engström, P
    Eriksson, T
    Storage protein accumulation during zygotic and somatic embryo development in Picea abies (Norway spruce)1990In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 80, no 3, p. 441-445Article in journal (Refereed)
    Abstract [en]

    Total protein was extracted from zygotic embryos and from somatic embryos of Picea abies (L.) Karst. (Norway spruce) cultured in vitro at different times during their development. An analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 2-dimensional gel electrophoresis of the protein extracts showed that protein composition and the temporal changes in protein abundance were very similar in the two embryo types. Both zygotic and somatic embryos accumulated storage proteins in abundance during their maturation phase of growth; the somatic embryos when cultured on medium containing 90 mM sucrose and 7.6 μM ABA. The major storage proteins are composed of polypeptides with molecular masses of about 22, 28, 33 and 42 kDa and they are identical in both embryo types according to their molecular mass and average isoelectric points. These proteins are also the most abundant proteins in the female gametophytic tissue of the mature seed. 

  • 24.
    Hakman, Inger
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    von Arnold, S.
    Plantlet regeneration in vitro via adventitious buds and somatic embryos in Norway spruce (Picea abies)1988In: Genetic manipulation of woody plants / [ed] James W. Hanover & Daniel E. Keathley , New York: Plenum Press , 1988, p. 199-215Chapter in book (Other academic)
  • 25.
    Hakman, Inger
    et al.
    Uppsala Universitet.
    von Arnold, Sara
    Isolation and growth of protoplasts from suspensions of Pinus contorta Dougl. ex Loud.1983In: Plant Cell Reports, Vol. 2, no 2, p. 92-94Article in journal (Refereed)
    Abstract [en]

    Cell suspensions were initiated from embryo derived calli of Pinus contorta. Some of these cell lines could be maintained in culture for at least one year without reduced growth. A high yield of protoplasts was obtained from the cell suspensions. The protoplasts started to divide after two days and cell clusters could be observed after about two weeks. The growth phase of the cell suspensions was very important for the division of protoplasts. Only protoplasts isolated from suspensions in an actively dividing phase were able to divide with a high frequency and to give rise to cell clusters. 

  • 26.
    Hakman, Inger
    et al.
    Inst, of Physiological Botany, Univ. of Uppsala.
    von Arnold, Sara
    Somatic embryogenesis and plant regeneration from suspension cultures of Picea glauca (White spruce).1988In: Physiologia Plantarum, ISSN 0031-9317, Vol. 72, no 3, p. 579-587.Article in journal (Refereed)
    Abstract [en]

    Plantlets were regenerated from long-term embryogenic cultures of Picea glauca (Moench) Voss. (White spruce). Embryogenic calli, initiated from immature zygotic embryos and maintained by monthly subculture for 16 months, were used to establish suspension cultures. Small somatic embryos were continuously produced in liquid culture medium containing auxin and cytokinin and the cultures showed a sustained regeneration capacity for >6 months. Somatic embryos propagated in the suspension cultures developed further into embryos bearing cotyledons, about 1 month after transfer to solidified medium containing abscisic acid. Electron microscopic examination revealed that storage nutrients, lipids, proteins and carbohydrates, accumulated in the somatic embryos during this treatment with abscisic acid (ABA). Upon subculture to medium lacking plant growth regulators such embryos could develop into small green plantlets. 

  • 27.
    Hakman, Inger
    et al.
    UNIV UPPSALA, INST PHYSIOL BOT, BOX 540, S-75121 UPPSALA, SWEDEN .
    Vonarnold, S
    Plantlet regeneration through somatic embryogenesis in Picea abies (Norway spruce)1985In: Journal of plant physiology (Print), ISSN 0176-1617, E-ISSN 1618-1328, Vol. 121, no 2, p. 149-158Article in journal (Refereed)
  • 28.
    Hakman, Inger
    et al.
    UNIV UPPSALA, INST PHYSIOL BOT, S-75121 UPPSALA, SWEDEN.
    Vonarnold, S
    Bengtsson, A
    Cytofluorometric measurements of nuclear-DNA in adventitious buds and shoots of Picea abies regenerated invitro1984In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 60, no 3, p. 321-325Article in journal (Refereed)
    Abstract [en]

    Nuclear DNA content of adventitious buds and shoots of Picea abies (L.) Karst. developed in vitro was compared to that of buds collected from field-grown trees. Protoplasts were isolated from the different tissues and after fixation and staining with ethidium bromide the DNA content of their interphase nuclei was determined cytofluorometrically. The DNA pattern of the different tissues was within the same range and had the same distribution with one main peak. 

  • 29.
    Hakman, Inger
    et al.
    UNIV UPPSALA, INST PHYSIOL BOT, BOX 540, S-75121 UPPSALA, SWEDEN .
    Vonarnold, S
    Eriksson, T
    Somatic embryogenesis in Norway spruce1985In: Physiologia Plantarum: An International Journal for Plant Biology, ISSN 0031-9317, E-ISSN 1399-3054, Vol. 64, no 2, p. A12-A12Article in journal (Refereed)
  • 30.
    Hakman, Inger
    et al.
    SWEDISH UNIV AGR SCI, DEPT PATHOL, S-75007 UPPSALA, SWEDEN .
    Vonarnold, S
    Fellnerfeldegg, H
    Isolation and DNA analysis of protoplasts from developing female gametophytes of Picea abies (Norway spruce)1986In: Canadian Journal of Botany, ISSN 0008-4026, E-ISSN 1480-3305, Vol. 64, no 1, p. 108-112Article in journal (Refereed)
    Abstract [en]

    Female gametophytes of Picea abies were collected during their growth period (June and July). Tissues were prepared for light microscope examination of their development and for protoplast isolation and further DNA measurements. From archegonia initiation to early embryo development, protoplasts could easily be obtained from such gametophytes. Stained and fixed nuclei, prepared from the protoplasts, were subjected to flow cytometry and their DNA content was recorded to be half that of seedling derived nuclei. 

  • 31.
    Hallberg, Henrik
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Auxin localization and polar auxin transport during somatic embryogenesis in Norway spruce.2008Conference paper (Other academic)
  • 32.
    Hallberg, Henrik
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Palovaara, Joakim
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Auxin polar transport and PIN localization pattern during conifer embryo development2010Conference paper (Other academic)
  • 33. Kartha, K K
    et al.
    Fowke, L C
    Leung, N L
    Caswell, K L
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Induction of somatic embryos and plantlets from cryopreserved cell-cultures of white spruce (Picea glauca)1988In: Journal of plant physiology (Print), ISSN 0176-1617, E-ISSN 1618-1328, Vol. 132, no 5, p. 529-539Article in journal (Refereed)
  • 34.
    Liew, Josefine
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Andersson, Lars
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Boström, Ullalena
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Forkman, Johannes
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Influence of temperature and photoperiod on sprouting capacity of Cirsium arvense and Sonchus arvensis root buds2012In: Weed research (Print), ISSN 0043-1737, E-ISSN 1365-3180, Vol. 52, no 5, p. 449-457Article in journal (Refereed)
    Abstract [en]

    Influence of temperature and photoperiod on sprouting capacity of Cirsium arvense and Sonchus arvensis root buds. Weed Research.52, 449-457. Summary Timing of treatment is a key to successful and sustainable weed management. For perennial weeds, highly energy-demanding, repeated stubble cultivation or tillage is a common strategy in organic agriculture. The fragmentation of underground material stimulates root buds to grow and, if repeated, significantly reduces the energy and nutrient resources of the roots. However, the effect might differ depending on variation in sprouting over the season and among species. Here, we studied the impact of different photoperiods and temperatures on sprouting capacity of root buds of Cirsium arvense and Sonchus arvensis in a climate chamber experiment. Two populations of each species, collected in northern and southern Sweden, were used. Plants were exposed to long (18 h), short (12 h) or decreasing (from 18 to 8 h) photoperiods in combinations with high (18/12 degrees C for 16/8 h), low (12/6 degrees C), decreasing (from 21 to 5 degrees C in 4 weeks) or constant high (16 degrees C) temperatures. Sprouting capacity was evaluated based on the proportion of sprouting buds from short root fragments. Neither temperature nor photoperiod affected root bud sprouting in C. arvense, while in S. arvensis, photoperiod seemed to regulate sprouting capacity. The proportion of sprouted buds decreased in short photoperiods, especially if combined with high temperature. In northern conditions, this suggests that weeding strategies based on fragmentation of the root system of S. arvensis will have low efficiency if the autumns are warm.

  • 35.
    Liew, Josefine
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Andersson, Lars
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Boström, Ullalena
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Forkman, Johannes
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Hakman, Inger
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Regeneration capacity from buds on roots and rhizomes in five herbaceous perennials as affected by time of fragmentation2013In: Plant Ecology, ISSN 1385-0237, E-ISSN 1573-5052, Vol. 214, no 10, p. 1199-1209Article in journal (Refereed)
    Abstract [en]

    Variation in seasonal sprouting pattern from roots and rhizomes of perennial herbaceous plants influence the success of plant proliferation ability, invasiveness and escape from weed control measures. The latter often rely on methods, which repeatedly fragment the underground system, thereby trigger adventitious and axillary buds to sprout, and consequently reduce the amount of stored energy. If carried out at times when no re-growth occurs, treatments will have little effect on weed populations, but cost much in terms of labour and energy. The purpose of this experiment was to determine the seasonal variation in bud sprouting capacity after fragmentation. Five troublesome perennial weed species, collected in northern and southern Sweden, were grown outdoors in Uppsala, Sweden (N 59°49′, E 17°39′), from May 2009 to January 2010. Cut root and rhizome fragments, taken at two weeks intervals from July to January, were used to evaluate bud sprouting capacity, which was statistically analyzed using generalized additive models. In Elytrigia repens from southern Sweden and Sonchus arvensis sprouting capacity was significantly impaired during a period from September to November. In Equisetum arvense and Tussilago farfara sprouting was low between July and November where after it increased. In contrast, Cirsium arvense and E. repens from northern Sweden sprouted readily throughout the period. Except for E. repens, a model by populations was significantly better than one based on latitudinal origin. The result suggests a species-specific timing of treatments in weed management, avoiding the non-effective autumn period for E. arvense, S. arvensis and T. farfara, and in some cases in E. repens.

  • 36.
    Liew, Josefine
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Andersson, Lars
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Boström, Ullalena
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Forkman, Johannes
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Seasonal variation and control of sprouting capacity of Cirsium arvense and Sonchus arvensis root buds2011In: NJF Report Vol 7 No 9 2011. (Sem 446) Risk assessment/risk management, forecasting pests and diseases of field crops in a changing climate, 2011Conference paper (Refereed)
  • 37.
    Liew, Josefine
    et al.
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Andersson, Lars
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Boström, Ullalena
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Magnuski, Ewa
    Swedish University of Agricultural Sciences, Department of Crop Production Ecology.
    Milberg, Per
    Seasonal variation in sprouting capacity from underground root buds of Cirsium arvense and Sonchus arvensis2010In: Proceedings 15th European Weed Research Society Symposium, Kaposvár, 2010, p. 52-Conference paper (Refereed)
  • 38. Liew, Josefine
    et al.
    Boström, Ullalena
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Karlsson, Laila
    Magnuski, Eva
    Milberg, Per
    Andersson, Lars
    Reduced bud sprouting from intact roots and rhizomes of perennial weeds in Sweden during autumn.2009Conference paper (Other academic)
  • 39. Oliviusson, P.
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    A tonoplast intrinsic protein, a-TIP is present in seeds and somatic embryos of Norway spruce (Picea abies).1995In: Kluwer Academic Publishers Current Issues in Plant Molecular and Cellular Biology / [ed] M. Terzi, R. Cella & A. Falavigna, lorence, Italy, 12-17 June, 1994, 1995Conference paper (Refereed)
  • 40. Oliviusson, P
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    A tonoplast intrinsic protein (tip) is present in seeds, roots and somatic embryos of Norway spruce (picea-abies)1995In: Physiologia plantarum, Vol. 95 (2), p. 288-295Article in journal (Refereed)
  • 41. Oliviusson, P
    et al.
    Salaj, J
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Expression pattern of transcripts encoding water channel-like proteins in Norway spruce (Picea abies)2001In: Plant molecular biology, Vol. 46 (3), p. 289-299Article in journal (Refereed)
  • 42.
    Palovaara, Joakim
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Expression dynamic of a PIN homologous gene during Norway spruce (Picea abies) somatic embryogenesis. .2008Conference paper (Other academic)
  • 43.
    Palovaara, Joakim
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Expression pattern of a WOX-like transcription factor during somatic embryo development in Norway spruce (Picea abies).2006Conference paper (Other academic)
  • 44.
    Palovaara, Joakim
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    WOX2 and polar auxin transport during spruce embryo pattern formation2009In: Plant Signalling & Behavior, ISSN 1559-2316, E-ISSN 1559-2324, Vol. 4, no 2, p. 153-155Article in journal (Other academic)
    Abstract [en]

    The WOX family of transcription factors and polar auxin transport (PAT) are both essential for embryonic patterning and thus normal embryo development in angiosperms. Recent analysis by us of WOX-related genes in Picea and Pinus suggests that they play fundamental roles during embryo development also in conifers.1 It has been proposed that there is a connection between the spatial separation of WOX2 and WOX8, and PAT in the formation of the apical-basal axis in Arabidopsis embryos and that both are involved in the regulation of the auxin efflux carrier PIN1. Auxin also seems to play a crucial role in apical-basal axis formation in conifer embryos based on studies using the polar auxin inhibitor NPA. We recently analyzed the expression of a PIN1-like gene in NPA-treated and untreated precotyledonary somatic spruce embryos and could see a significant upregulation of the PIN1-like gene in the NPA-treated embryos.2 Here we show that PaWOX2 is also significantly upregulated in the same embryos. Taken together, this suggests that PAT is involved in regulating both PIN1 and WOX2 expression in conifers and strengthens the evidence for the proposed connection between WOX and PIN genes in seed plants.

  • 45.
    Palovaara, Joakim
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hallberg, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Stasolla, Claudio
    Plant Science, University of Manitoba.
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Comparative expression pattern analysis of WUSCHEL-related homeobox 2 (WOX2) and WOX8⁄9 in developing seeds and somatic embryos of the gymnosperm Picea abies2010In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 188, no 1, p. 122-135Article in journal (Refereed)
    Abstract [en]

    In seed plants, current knowledge concerning embryonic pattern formation by polar auxin transport (PAT) and WUSCHEL-related homeobox (WOX) gene activity is primarily derived from studies on angiosperms, while less is known about these processes in gymnosperms. In view of the differences in their embryogeny, and the fact that somatic embryogenesis is used for mass propagation of conifers, a better understanding of embryo development is vital.

    The expression patterns of PaWOX2 and PaWOX8/9 were followed with quantitative reverse transcription–polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH) during seed and somatic embryo development in Norway spruce (Picea abies), and in somatic embryos treated with the PAT inhibitor N-1-naphthylphthalamic acid (NPA).

    Both PaWOX2 and PaWOX8/9 were highly expressed at the early growth stages of zygotic and somatic embryos, and shared a similar expression pattern over the entire embryo. At later embryo stages, high expression of PaWOX8/9 became restricted to cotyledon primordia, epidermis, procambium and root apical meristem (RAM), which became most evident in NPA-treated somatic embryos, while expression of PaWOX2 was much lower.

    Our results suggest an ancestral role of WOX in seed plant embryo development, and strengthen the proposed connection between PAT, PIN-FORMED (PIN) and WOX in the regulation of embryo patterning in seed plants.

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

  • 46.
    Palovaara, Joakim
    et al.
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Hallberg, Henrik
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Stasolla, Claudio
    Luit, Bert
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Expression dynamics of PIN1 and WOX genes during Norway spruce (Picea abies) somatic embryogenesis.2009Conference paper (Other academic)
  • 47.
    Palovaara, Joakim
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Hallberg, Henrik
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Stasolla, Claudio
    Plant Science, University of Manitoba.
    Luit, Bert
    Plant Science, University of Manitoba.
    Hakman, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Expression of a gymnosperm PIN homologous gene correlates with auxin immunolocalization pattern at cotyledon formation and in demarcation of the procambium during Picea abies somatic embryo development and in seedling tissues2010In: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 30, no 4, p. 479-489Article in journal (Refereed)
    Abstract [en]

    In seed plants, the body organization is established during embryogenesis and is uniform across gymnosperms and angiosperms, despite differences during early embryogeny. Evidence from angiosperms implicates the plant hormone auxin and its polar transport, mainly established by the PIN family of auxin efflux transporters, in the patterning of embryos. Here, PaPIN1 from Norway spruce (Picea abies [L.] Karst.), a gene widely expressed in conifer tissues and organs, was characterized and its expression and localization patterns were determined with reverse transcription polymerase chain reaction and in situ hybridization during somatic embryo development and in seedlings. PaPIN1 shares the predicted structure of other PIN proteins, but its central hydrophilic loop is longer than most PINs. In phylogenetic analyses, PaPIN1 clusters with Arabidopsis thaliana (L.) Heynh. PIN3, PIN4 and PIN7, but its expression pattern also suggests similarity to PIN1. The PaPIN1 expression signal was high in the protoderm of pre-cotyledonary embryos, but not if embryos were pre-treated with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). This, together with a high auxin immunolocalization signal in this cell layer, suggests a role of PaPIN1 during cotyledon formation. At later stages, high PaPIN1 expression was observed in differentiating procambium, running from the tip of incipient cotyledons down through the embryo axis and to the root apical meristem (RAM), although the mode of RAM specification in conifer embryos differs from that of most angiosperms. Also, the PaPIN1 in situ signal was high in seedling root tips including root cap columella cells. The results thus suggest that PaPIN1 provides an ancient function associated with auxin transport and embryo pattern formation prior to the separation of angiosperms and gymnosperms, in spite of some morphological differences.

  • 48. Salajova, T
    et al.
    Jasik, J
    Kormutak, A
    Salaj, J
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Embryogenic culture initiation and somatic embryo development in hybrid firs (Abies alba x Abies cephalonica, and Abies alba x Abies numidica)1996In: Plant cell reports, Vol. 15 (7), p. 527-530Article in journal (Refereed)
  • 49. Segura-Aguilar, Juan
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Rydström, Jan
    Generation of free-radicals in germinating Norway spruce – differences in the effect of 2 different phenolic-compounds1994In: Proceedings of the Royal Society of Edinburgh. Section B, Biological sciences, Vol. 102, p. 203-210Article in journal (Refereed)
  • 50. Segura-Aguilar, Juan
    et al.
    Hakman, Inger
    University of Kalmar, School of Pure and Applied Natural Sciences.
    Rydström, Jan
    Studies on the mode of action of the herbicidal effect of 2,4,5-trichlorophenoxyacetic acid on germinating Norway spruce1995In: Environmental and experimental botany, Vol. 35 (3), p. 309-315Article in journal (Refereed)
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