The effect of nitrogen source on photosynthesis of carob at high CO2 concentrations

C. Cruz, S. H. Lips, M. A. Martins‐Loução

    Research output: Contribution to journalArticlepeer-review

    22 Scopus citations


    Carob seedlings (Ceratonia siliqua L. cv. Mulata), fed with nitrate or ammonium, were grown in growth chambers containing two levels of CO2 (360 or 800 μl l−1), three root temperatures (15, 20 or 25°C), and the same shoot temperature (20/24°C, night/day temperature). The response of the plants to CO2 enrichment was affected by environmental factors such as the type of inorganic nitrogen in the medium and root temperature. Increasing root temperature enhanced photosynthesis rate more in the presence of nitrate than in the presence of ammonium. Differences in photosynthetic products were also observed between nitrate‐ and ammonium‐fed carob seedlings. Nitrate‐grown plants showed an enhanced content of sucrose, while ammonium led to enhanced storage of starch. Increase in root temperature caused an increase in dry mass of the plants of similar proportions in both nitrogen sources. The enhancement of the rates of photosynthesis by CO2 enrichment was proportionally much larger than the resulting increases in dry mass production when nitrate was the nitrogen source. Ammonium was the preferred nitrogen source for carob at both ambient and high CO2 concentrations. The level of photosynthesis of a plant is limited not only by atmospheric CO2 concentration but also by the nutritional and environmental conditions of the root.

    Original languageEnglish
    Pages (from-to)552-556
    Number of pages5
    JournalPhysiologia Plantarum
    Issue number3
    StatePublished - 1 Jan 1993


    • Ceratonia siliqua
    • elevated CO
    • growth
    • nitrogen
    • root temperature

    ASJC Scopus subject areas

    • Physiology
    • Genetics
    • Plant Science
    • Cell Biology


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