Uptake regions of inorganic nitrogen in roots of carob seedlings

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

    Research output: Contribution to journalArticlepeer-review

    34 Scopus citations


    Three‐week‐old seedlings of carob (Ceratonia siliqua L. cv. Mulata) were grown for 9 weeks under different root temperatures (20, 30 and 40°C) at pH values of 5, 7 and 9 with nitrate or ammonium as nitrogen source. Nitrogen uptake rates were determined by depletion from the medium and decreased with distance from the apex. The decline of nitrogen uptake rates along the roots depended on the form of inorganic nitrogen in the medium as well as on pH and temperature, such that the NO3 and NH+4 ions were taken up essentially by the root tips (0–2 cm) through processes requiring energy. The uncharged NH3 species entered passively, through the mature parts of the root (2–10 cm). Root zone temperature and pH affect the NH+4/NH3 equilibrium in the nutrient solution and, consequently, the uptake areas of the root for these ions. Furthermore. while root tip uptake of nitrogen is energy dependent, uptake through mature root areas is essentially passive and seems to depend on a well developed apparent free space.

    Original languageEnglish
    Pages (from-to)167-175
    Number of pages9
    JournalPhysiologia Plantarum
    Issue number2
    StatePublished - 1 Jan 1995


    • Ammonium
    • Ceratonia siliqua
    • carob
    • nitrate
    • nitrogen
    • uptake

    ASJC Scopus subject areas

    • Physiology
    • Genetics
    • Plant Science
    • Cell Biology


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