Nitrogen use efficiency by a slow-growing species as affected by CO 2 levels, root temperature, N source and availability

Cristina Cruz, Herman Lips, Maria Amélia Martins-Loução

    Research output: Contribution to journalArticlepeer-review

    25 Scopus citations


    This study examines the importance of N source and concentration on plant response to distinct CO2 concentrations and root temperatures. The experimental design of this work was a factorial combination of: CO2 concentration, nitrogen concentration, nitrogen source and root temperature. Carob (Ceratonia siliqua L.) was assessed as a potential model of a slow growing Mediterranean species. The results showed that: 1) biomass increment under high CO2 varied between 13 and 100% in relation to plants grown under the same conditions but at ambient CO2 concentrations, depending on the root temperature and nitrogen source; 2) nitrate-fed plants attained a larger increase in biomass production compared to ammonium-fed ones. This performance seems to be linked to the co-ordinated regulation of the activities of glutamine synthetase and sucrose phosphate synthase. The variations in the magnitude and nature of growth responses to elevated CO 2 observed resulted in substantial changes in the chemical composition of the plant material and consequently in plant nitrogen use efficiency. Although performed with seedlings and under controlled conditions, this work emphasizes the importance of the nitrogen source used by the plants, a factor rarely taken into consideration when forecasting plant responses to global changes. Particularly, the results presented here, highlight the potential for uncoupling biomass accumulation from increment of air CO 2 concentration and show that more than nitrogen availability N source may offset positive plant growth responses under elevated CO2 and root temperature.

    Original languageEnglish
    Pages (from-to)1421-1428
    Number of pages8
    JournalJournal of Plant Physiology
    Issue number12
    StatePublished - 1 Jan 2003


    • Ammonium
    • Carbon and nitrogen
    • Ceratonia siliqua
    • High CO
    • Nitrate
    • Nitrogen source
    • Root temperature

    ASJC Scopus subject areas

    • Physiology
    • Agronomy and Crop Science
    • Plant Science


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