| 1. |
- Gruffman, Linda, et al.
(författare)
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Cultivation of Norway spruce and Scots pine on organic nitrogen improves seedling morphology and field performance
- 2012
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 276, s. 118-124
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen availability exerts a significant control on biomass allocation of plants including Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris (L)) in boreal forest ecosystems. Recent studies suggest, however, this control differs for inorganic and organic nitrogen sources. The importance of the chemical form of nitrogen (inorganic or organic) for the morphology and growth of conifer seedlings was studied during production of seedlings in a forest nursery and subsequently in a field trial in northern Sweden. Seedlings were supplied with two different nutrient solutions; an inorganic conventional fertilizer and an organic, amino acid-based fertilizer. Seedlings cultivated on the organic nitrogen source displayed larger root systems resulting in a higher root: shoot ratio than did seedlings cultivated on the inorganic nitrogen source. The proportion of fine roots to lateral roots and the root tip proportion colonized by mycorrhiza were positively affected by the organic nitrogen source. Norway spruce seedlings cultivated on organic nitrogen displayed significantly increased shoot growth compared to seedlings cultivated on inorganic nitrogen. Our results suggest that the chemical form of nitrogen influences the allocation of biomass in conifer seedlings. The shift in allocation of resources to root biomass further leads to a competitive advantage in field conditions, resulting in a significant increase in shoot growth one year following transplant. (C) 2012 Elsevier B.V. All rights reserved.
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| 2. |
- Hedwall, Per-Ola, et al.
(författare)
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Interplay between N-form and N-dose influences ecosystem effects of N addition to boreal forest
- 2018
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Ingår i: Plant and Soil. - : Springer Science and Business Media LLC. - 0032-079X .- 1573-5036. ; 423, s. 385-395
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen (N) addition effects on boreal forest ecosystem are influenced by an interplay between N-form and N-dose. We hypothesize that trees take up organic N more efficiently than inorganic N and that unwanted side-effects of organic N are smaller. We predicted that 1) the tree growth response to arginine (ARG) addition is larger than to ammonium-nitrate (AN) and, 2) understory vegetation and ectomycorrhizal (EcM) changes following ARG addition are smaller than following AN addition.We investigated the effects of AN and ARG addition (50 and 150 kg N ha(-1)) during five years on tree growth, understory vegetation and EcM fungi in a Pinus sylvestris L. forest (c 50 years old) in northern Sweden.N addition increased tree growth and changed understory vegetation composition with few significant differences between AN and ARG. Differences in responses mainly occurred for the bryophyte Pleurozium schreberi which decreased more from ARG, and for EcM sporocarps, which sharply declined from AN, but not from ARG.We found very few differences in responses between AN and ARG addition with the exception of EcM and bryophytes. These species groups have several key functions in boreal forests and the differences in responses merits further investigations.
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| 3. |
- Ishida, Takahide
(författare)
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Ectomycorrhizal fungal community in alkaline-saline soil in northeastern China
- 2009
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 0940-6360 .- 1432-1890. ; 19, s. 329-335
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Tidskriftsartikel (refereegranskat)abstract
- Alkaline-saline soil is widespread in arid and semiarid regions of the world and causes severe environmental and agricultural problems. To advance our understanding of the adaptation of ectomycorrhizal fungi (EMF) to alkaline-saline soil, we investigated EMF communities on Mongolian willow (Salix linearistipularis) growing in alkaline-saline soil (up to pH 9.2) in northeastern China. In total, 75 root samples were collected from 25 willow individuals over 4.7 ha. To identify fungal species in ectomycorrhizal root tips, we used terminal restriction fragment length polymorphism and sequencing analyses of the internal transcribed spacer region of ribosomal DNA. We detected 11 EMF species, including species of Inocybe, Hebeloma, and Tomentella of the Basidiomycota and three Ascomycota species. The EMF richness of the study site was estimated to be 15-17 using major estimators. The most abundant species was Geopora sp. 1, while no Geopora-dominated EMF communities have been reported so far. Phylogenetic analysis showed that the phylogroup including Geopora sp. 1 has been found mostly in alkaline soil habitats, indicating its adaptation to high soil pH. Because EMF are indispensable for host plant growth, the EMF species detected in this study may be useful for restoration of alkaline-saline areas.
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| 4. |
- Ishida, Takahide, et al.
(författare)
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No evidence that nitrogen enrichment affect fungal communities of Vaccinium roots in two contrasting boreal forest types
- 2010
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Ingår i: Soil Biology and Biochemistry. - : Elsevier BV. - 0038-0717 .- 1879-3428. ; 42, s. 234-243
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Tidskriftsartikel (refereegranskat)abstract
- In boreal forests ericaceous shrubs often dominate the forest floor vegetation. Nitrogen enrichment has been shown to decrease shrub abundance and in this study we explored whether it also affects the root associated fungal communities. Fine roots of Vaccinium myrtillus were collected in a Norway spruce dominated forest and of Vaccinium vitis-idaea in a Scots pine dominated forest. In both forests, nitrogen enrichment was experimentally induced by adding 12.5 and 50 kg N ha(-1) yr(-1) for 12 (spruce forest) and four (pine forest) years. Based on terminal restriction fragment length polymorphisms, subdoning and sequencing analyses, the root associated fungal communities were examined. We found 93 fungal species including Asco-, Basidio- and Zygo-mycota. In general, the Rhizoscyphus ericae aggregate was the most dominant and this was followed by Herpotrichiellaceae and Sebacina. Ordination analysis revealed that nitrogen enrichment did not change species composition of the fungal communities in neither the spruce nor the pine forest, while fungal community structures were clearly discriminated between the dominant shrub species in each forest. Similarly, no fungal species showed a significant response to nitrogen enrichment. Therefore, nitrogen enrichment appears to have no effect on root associated fungi of understorey dwarf shrubs in boreal forests, while it is clear that spruce and pine forests harbor distinctive communities of these fungi. (C) 2009 Elsevier Ltd. All rights reserved.
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