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Nutrient effects on nodulation and N2 fixation in actinorhizal symbioses

Gentili, Francesco (2003). Nutrient effects on nodulation and N2 fixation in actinorhizal symbioses. Diss. (sammanfattning/summary) Umeå : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Agraria, 1401-6249 ; 392
ISBN 91-576-6444-7
[Doctoral thesis]

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In Frankia-actinorhizal symbioses phosphorus and nitrogen greatly affect nodulation as well as plant growth. In this thesis I studied how phosphorus and nitrogen affect nodulation in two actinorhizal plants having different infection pathways, the root hair infected Alnus incana (L.) Moench and the intercellularly infected Hippophaë rhamnoides L. Furthermore, I studied the possibility to use N2-fixing and non-N2-fixing plants for land reclamation of Italian marginal clay soils. The methods were performed in the laboratory as well as in the field, thus to combine studies of high precision (laboratory work) and high relevance (field work). In both species studied phosphorus stimulation and nitrogen inhibition of nodulation were systemic, indicating that the shoot takes active part in regulating nodulation. Further, phosphorus and nitrogen effects were specific on nodulation and not mediated via plant growth. In Alnus incana phosphorus stimulation and nitrogen inhibition was found to occur already at an early stage, cortical cell divisions, in nodule formation. In Hippophaë rhamnoides phosphorus stimulated nodulation as well as N2 fixation and nitrogen uptake, measured by 15N techniques. The land reclamation experiment showed that N2-fixing and non-N2-fixing plants, in particular drought tolerant species, can be used to reclaim the soil studied. In conclusion, phosphorus stimulation and nitrogen inhibition of nodulation occurred in actinorhizal plants having different infection pathways indicating a generality of the observed nutrient effects. The phosphorus stimulation of nodulation could be explored in field to increase nodulation, N2 fixation and yield of N2-fixing plants, but the possible uptake of P by mycorrhiza in field should be considered. Land reclamation of marginal clay soils is a long-term process but my studies show the potential use of actinorhizal plants in this process.

Authors/Creators:Gentili, Francesco
Title:Nutrient effects on nodulation and N2 fixation in actinorhizal symbioses
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Agraria
Year of publishing :May 2003
Number of Pages:27
ALLI. Gentili F & Huss-Danell K. 2002. Phosphorus modifies the effects of nitrogen on nodulation in split-root systems of Hippophaë rhamnoides. New Phytologist 153: 53-61. II. Gentili F & Huss-Danell K. 2003. Systemic and local phosphorus and nitrogen effects on nodulation and N2 fixation in Alnus incana. Manuscript. III. Gentili F & Huss-Danell K. 2003. Phosphorus and nitrogen affect early stages of nodule formation in Alnus incana. Manuscript. IV. Gentili F, Högberg P & Huss-Danell K. 2003. Phosphorus, nitrogen and their interaction affect N2 fixation and nitrogen isotope discrimination during nitrogen uptake in Hippophaë rhamnoides. Manuscript.
Place of Publication:Umeå
ISBN for printed version:91-576-6444-7
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:F Plant production > F62 Plant physiology - Growth and development
P Natural resources > P34 Soil biology
Subjects:Not in use, please see Agris categories
Agrovoc terms:root nodulation, growth, nitrogen fixation, phosphorus, mycorrhizae, root nodules, frankia, hippophae
Keywords:nitrogen fixation
Permanent URL:
ID Code:250
Department:?? 4043 ??
Deposited By: Staff Epsilon
Deposited On:12 May 2003 00:00
Metadata Last Modified:02 Dec 2014 10:03

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