| 1. |
- Agback, Peter, et al.
(författare)
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Root morphology and cluster root formation by seabuckthorn (Hippophae rhamnoides L.) in response to nitrogen, phosphorus and iron deficiency
- 2015
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 397, s. 75-91
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Tidskriftsartikel (refereegranskat)abstract
- The aims were to investigate effects of availability of nitrogen (N), phosphorus (P) and iron (Fe) on root properties of seabuckthorn (HippophaA << rhamnoides) and to test the hypothesis that seabuckthorn is able to form cluster roots (CRs).Two sources of seabuckthorn were used: the seabuckthorn cultivar BHi10726 originating from a breeding programme based on H.r. ssp mongolica and carried out in rich agricultural field soil in the black earth (chernozem) region of Russia and the seabuckthorn accession named Pk originating in a natural population of H.r. ssp turkestanica in the mountainous region of northern Pakistan. Three cultivation systems giving different water availabilities were used at two levels each of N, P and Fe. Root morphology of seedlings and clones was characterized and metabolite content in extracts of young and old CRs of Pk was analyzed by proton nuclear magnetic resonance spectroscopy.Availability of N affected growth and distribution of biomass between shoot and root, while P and Fe deficiency modified root system architecture towards more lateral roots. Densely positioned rootlets with a determinate type of growth consistent with the definition of CR were observed under low P and low Fe. Pk formed on average 12 CRs per plant, which was 3 to 4-fold higher compared to BHi10726 also when normalized per root length. Malate and glycine were most abundant of the organic acids and amino acids, respectively, and decreased in old CRs.Seabuckthorn has the ability to form cluster roots especially in Pk and under deficiency of P and Fe. The two sources of seabuckthorn with different histories showed distinctly different root system architectures. The high contents of malate and glycine and their decrease in old CRs may reflect roles in CR metabolism.
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| 2. |
- Lundquist, Per-Olof
(författare)
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Nodule inhabiting non-rhizobial bacteria and their influence on growth of selected leguminous plants of Bangladesh
- 2016
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Ingår i: Bioresearch communications. - 2411-0485 .- 2411-0272. ; 2, s. 134-138
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Tidskriftsartikel (refereegranskat)abstract
- The present study aimed to identify non-rhizobial bacteria present in the root nodules of four legume plants viz. Arachis hypogaea L., Dolichos lablab L., Vigna mungo L., and Sesbania sesban L. grown in Bangladesh. Pure isolates of the bacteria obtained from the surface sterilized root nodules were identified by sequencing of 16S rRNA gene. A total of 13 isolates belonging to 10 genera under 7 families were obtained. Effects of these non-rhizobial bacteria on nodulation, plant height, shoot biomass, and leaf chlorophyll contents were compared in between A. hypogaeae L. and V. mungo L. Of all the isolates identified, Klebsiella sp. and Enterobacter sp. produced nodules in both V. mungo L. and A. hypogaea L. and Bacillus sp. produced nodules only in V. mungo L. Results also demonstrated that most of the isolates enhanced shoot height, shoot biomass and leaf chlorophyll contents in V. mungo L. but not in A. hypogaea L. Results of the present study are thus relevant for enhancing our knowledge about the beneficial use of non-rhizobial bacterial in growth and development of leguminous crops in order to secure sustainable agriculture.
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| 3. |
- Lundquist, Per-Olof, et al.
(författare)
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Root traits of seabuckthorn
- 2016
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Ingår i: RPD Abstracts. - 2255-8624 .- 2500-9788. ; 2, s. 87-87
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 4. |
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| 5. |
- Shah, Syed Rehmat Ullah, et al.
(författare)
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Shoot organogenesis from roots of seabuckthorn (Hippophaë rhamnoides L.): structure, initiation and effects of phosphorus and auxin
- 2015
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Ingår i: Trees - Structure and Function. - : Springer Science and Business Media LLC. - 0931-1890 .- 1432-2285. ; 29, s. 1989-2001
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Tidskriftsartikel (refereegranskat)abstract
- Shoots from roots formed on seedlings in vitro in the groove of lateral roots as on plants growing in a natural habitat. The finding has ecological and applied relevance.Shoot organogenesis from roots (root suckers, shoots from roots, SfRs) allows vegetative propagation of the small tree seabuckthorn (HippophaA << rhamnoides L.) in addition to sexual propagation and is an important trait associated with the root system. Using an in vitro system, we studied initiation, localization and development of SfRs and interacting roles of phosphorus (P) and indole-3-acetic acid (IAA). After transfer of seedlings to the W4 medium (WPM medium with added IAA, benzyl adenine and giberellic acid), SfRs protruded after 2 weeks from the primary root initially at the groove of lateral roots (LR) as seen by scanning electron microscopy and light microscopy. This is also the location of SfRs on plants growing in natural conditions, which suggests a similar developmental pathway. To localize SfR initiation, staining by the DNA-binding fluorochrome 4',6-diamidino-2-phenylindole in root cross sections revealed a high density of small cells as in meristems in the pericycle area between endodermis and vascular tissue. During 8-10 weeks, SfRs emerged also in other positions on the primary root, concomitantly with senescence of existing LRs and suppression of new LR formation. Since SfR formed in relation to LRs, we hypothesized that P and IAA play a role in SfR formation. Highest production of SfRs occurred in W4 medium after pre-treatment with high P in the presence of IAA while LR production in WPM was stimulated by IAA in low and middle P. SfRs developed in vitro on seedlings originating from three subspecies of H. rhamnoides showing this trait to be common. This experimental system allowed studies of organogenesis of SfRs and LRs in response to plant growth regulators, P and IAA and may be further implemented in basic studies and in applied clonal propagation of seabuckthorn.
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| 6. |
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| 7. |
- Westerbergh, Anna, et al.
(författare)
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Towards the Development of Perennial Barley for Cold Temperate Climates—Evaluation of Wild Barley Relatives as Genetic Resources
- 2018
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Ingår i: Sustainability. - : MDPI AG. - 2071-1050. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Perennial cereal crops could limit the negative impacts of agriculture on the environment and climate change. In cold temperate climates, perennial plants must be adapted to seasonal changes and abiotic stresses, such as frost, to be able to regrow for several years. Wild crop relatives that are perennials and already adapted to cold temperate climates may provide genetic resources for breeding new perennial cereal grain crops. Barley (Hordeum vulgare) is one of the most important cereals in northern agricultural areas, and its related perennial species may be good candidates for the development of perennial cereals. We evaluated a diverse set of 17 wild perennial Hordeum species represented by 67 accessions in field conditions with a cold winter climate and long days during summer in Central Sweden (latitude 60 degrees N). Six species (H. brevisubulatum, H. bulbosum, H. fuegianum, H. jubatum, H. lechleri and H. secalinum) showed regrowth and formation of spikes for four seasons. The most distant perennial relative of barley, H. stenostachys, showed weak regrowth. H. bulbosum, the closest perennial barley relative, had a large number of accessions with wide geographic origins that showed good regrowth. Together with its storage bulbs and its cross-compatibility with barley, this makes H. bulbosum an important genetic resource for the development of perennial Hordeum grains using either the domestication or the wide-hybridization strategy.
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| 8. |
- Zhao, Enid Ming, et al.
(författare)
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Intercropping affects genetic potential for inorganic nitrogen cycling by root-associated microorganisms in Medicago sativa and Dactylis glomerata
- 2017
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Ingår i: Applied Soil Ecology. - : Elsevier BV. - 0929-1393 .- 1873-0272. ; 119, s. 260-266
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Tidskriftsartikel (refereegranskat)abstract
- The effect of intercropping on the genetic potential for N-cycle pathways promoting either retention or loss of N by the microbial communities associated to the roots or present in the bulk soil for two forage crops was studied in a greenhouse experiment. Medicago sativa ('lucerne') and Dactylis glomerata ('cocksfoot') were grown as sole crops or intercropped in soils with or without addition of biogas digestate to also evaluate fertilizer effects. Eight genes involved in inorganic N-cycling were quantified using real-time PCR to determine the genetic potential for different N-cycling pathways. Both plant species and intercropping affected the abundance of root-associated microbial-derived genes involved in N-cycling processes, while there was no effect of amendment with biogas digestate. The genetic potential for the various pathways differed between bulk soil and roots, as well as between the roots of the two plant species, suggesting that organisms involved in different N-cycling processes were favored in different compartments in the soil-root environment. Ammonia oxidizers involved in nitrification, a pathway resulting in N-leaching, dominated in soil whereas those related to N-2 fixation and gaseous N losses (denitrification) were more abundant on roots. We also observed niche differentiation between the two major groups of organisms with the capacity to reduce N2O in the root- and soil compartment. Legume-grass intercropping resulted in a decreasing trend for several root- associated functional communities. More specifically, the legume exerted an effect on the N-cycling communities on the roots of both the legume and grass species, which suggests altered plant-microbial or microbial-microbial interactions during intercropping.
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