Growth and nitrogen relations in reciprocal grafts of wild-type and nitrate reductase-deficient mutants of pea (Pisum sativum L. var. Juneau)

Plants growing on NO3- differ in the proportion of NO3- reduced in their roots and leaves. Using a version of a two-compartment, two-resource plant growth simulation model, the possible effects of changing the N assimilation site on plant growth were explored. Subsequently, using an experimental sys...

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Bibliographic Details
Published in:Journal of experimental botany 1997-06, Vol.48 (6), p.1241-1250
Main Authors: Lexa, Matej, Cheeseman, John M.
Format: Article
Language:English
Subjects:
Agronomy. Soil science and plant productions
Biological and medical sciences
biomass partitioning
Chimeras
Economic plant physiology
Fundamental and applied biological sciences. Psychology
Graftage
grafting
mathematical model
Metabolism
Nitrates
Nitrogen
Nitrogen assimilation site
Nitrogen metabolism
Nitrogen metabolism and other ones (excepting carbon metabolism)
Nutrition. Photosynthesis. Respiration. Metabolism
Peas
Plant growth
Plant physiology and development
Plant roots
Plants
Regulation of Growth, Development and Whole Organism Physiology
Root growth
root:shoot ratio
Xylem
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Summary:Plants growing on NO3- differ in the proportion of NO3- reduced in their roots and leaves. Using a version of a two-compartment, two-resource plant growth simulation model, the possible effects of changing the N assimilation site on plant growth were explored. Subsequently, using an experimental system designed to vary the site of NO3- reduction; chimeras (reciprocal grafts) of Pisum sativum var. Juneau and its mutant, A317, deficient in nitrate reductase. Plant growth and N metabolism at varying NO3- levels were examined in a hydroponic system. In what is thought to be the first direct plant manipulation of this kind, total dry weight, root:shoot ratio, total N and NO3- concentrations, in vitro nitrate reductase activity, NO3- in xylem exudates, and leaf chlorophyll content were compared. It was found that changing the location of nitrate reduction did not change growth significantly and caused only subtle changes in N concentration. These indifferences occurred in spite of marked changes in growth associated with NO3- availability and useability. To achieve this kind of plasticity the plants must have dramatically altered the flow and storage of NO3- and reduced N. The results are compared with existing views of biomass partitioning and regulation of N assimilation.
ISSN:0022-0957
1460-2431
DOI:10.1093/jxb/48.6.1241