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Organic and inorganic nitrogen sources for conifer seedlings

abundance, uptake and growth

Öhlund, Jonas (2004). Organic and inorganic nitrogen sources for conifer seedlings. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ; 312
ISBN 91-576-6546-X
[Doctoral thesis]

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Even though the capacity of plants to absorb organic N compounds has been known since
the 1940.s it was not until recently that these N sources were recognized as a potentially
important source of N for plants. Thus, the classical paradigm that plants only use inorganic
N compounds and are forced to play a passive role acquiring N in excess of microbial demand
is today questioned. However, despite the accumulating amounts of studies suggesting
that plants have the capacity to absorb organic N at comparable rates to inorganic N the
quantitative importance of organic-N, as opposed to inorganic N, is still not understood. In
this thesis the focus has been to investigate the abundancy, uptake and growth of amino acids
in two economically important conifer species Scots pine (Pinus sylvestris L.) and Norway
spruce (Picea abies (L.) Karst.). Moreover, we also tried to examine to what extent amino
acids may contribute to the N budget of field grown Scotst pine seedlings. The results show
that Scots pine seedlings grown in a dry heath forest have acces to comparable or higher soil
solution concentration of free amino acids N compare to inorganic N sources. The seedlings
were also able to absorb amino acid N at the same or higher rates as inorganic N sources
both when these were supplied at higher concentration in greenhouse grown seedlings and at
lower more ecological relevant concentratons in field grown seedlings. Moreover, our growth
experiments suggested that amino acids are capable of supporting similar or even higher
growth in Scots pine seedlings compared to a commercial fertilizer based on NO₃⁻ and NH₄+.
The use of arginine as a source of N for growth of Scots pine seedling were also recorded to
give a much smaller N loss compared to the commercial fertilizer due to a strong adsorption
to the growth substrate. In all the results presented in this thesis strongly suggests that amino
acids is an important N source in the N economy of Scots pine and Norway spruce seedlings
and that these N sources may be a poteential alternative to inorganic N sources for comersial
seedling growth.

Authors/Creators:Öhlund, Jonas
Title:Organic and inorganic nitrogen sources for conifer seedlings
Subtitle:abundance, uptake and growth
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Silvestria
Year of publishing :May 2004
Number of Pages:38
I.Öhlund, J. & Näsholm, T. (2001) Growth of conifer seedlings on organic and inorganic nitrogen sources. Tree Physiology 21:1319-1326.
II.Öhlund, J. & Näsholm, T. (2002) Low Nitrogen Losses with a New Source of Nitrogen for Cultivation of Conifer Seedlings. Environmental Science and Technology 36:4854-4859.
III.Öhlund, J. & Näsholm, T. (2004) Regulation of organic and inorganic nitrogen uptake in Scots pine (Pinus sylvestris L.) seedlings. Submitted to Tree Physiology.
IV.Öhlund, J. & Näsholm, T. (2004) Mechanisms of amino acid uptake in Scots pine (Pinus sylvestris (L).) seedlings. Submitted to Planta.
V.Öhlund, J. & Näsholm, T. (2004) The abundance and utilization of dissolved nitrogen compounds in a Pinus sylvestris forest. Submitted to Ecosystems.
Place of Publication:Umeå
Publisher:Dept. of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
ISBN for printed version:91-576-6546-X
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F61 Plant physiology - Nutrition
F Plant production > F62 Plant physiology - Growth and development
Subjects:(A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 401 Agricultural, Forestry and Fisheries > Forest Science
Agrovoc terms:nitrogen, organic compounds, inorganic compounds, seedlings, picea abies, pinus sylvestris, growth, nutrient uptake
Keywords:organic N, amino acids, boreal forest, Scots pine, Norway spruce, uptake, growth
Permanent URL:
ID Code:569
Department:(S) > Dept. of Forest Genetics and Plant Physiology
Deposited By: Staff Epsilon
Deposited On:26 May 2004 00:00
Metadata Last Modified:02 Dec 2014 10:05

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