Abstract
We have established a simple soil-based
experimental system that allows a small and sustained restriction of growth
of Arabidopsis by low nitrogen (N). Plants were grown in a large
volume of a peat-vermiculite mix that contained very low levels of
inorganic N. As a control, inorganic N was added in solid form to the
peat-vermiculite mix, or plants were grown in conventional nutrient-rich
solids. The low N growth regime led to a sustained 20\% decrease of
the relative growth rate over a period of 2 weeks, resulting in a
two- to threefold decrease in biomass in 35- to 40-day-old plants.
Plants in the low N regime contained lower levels of nitrate, lower
nitrate reductase activity, lower levels of malate, fumarate and other
organic acids and slightly higher levels of starch, as expected from
published studies of N-limited plants. However, their rosette protein
content was unaltered, and total and many individual amino acid levels
increased compared with N-replete plants. This metabolic phenotype
reveals that Arabidopsis responds adaptively to low N by decreasing
the rate of growth, while maintaining the overall protein content,
and maintaining or even increasing the levels of many amino acids.
- 19054347
- acids,
- adaptation,
- amino
- arabidopsis
- arabidopsis,
- carbohydrates,
- nitrates,
- nitrogen,
- photoperiod,
- physiological,
- proteins,
- soil,
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