Functional aspects of root architecture and mycorrhizal inoculation with respect to nutrient uptake capacity

Abstract

ACESSO via B-on: http://dx.doi.org/10.1007/s00572-003-0254-5The aim of this research was to investigate theeffect of arbuscular mycorrhizal (AM) colonisation onroot morphology and nitrogen uptake capacity of carob(Ceratonia siliqua L.) under high and low nutrientconditions. The experimental design was a factorialarrangement of presence/absence of mycorrhizal fungusinoculation (Glomus intraradices) and high/low nutrientstatus. Percent AM colonisation, nitrate and ammoniumuptake capacity, and nitrogen and phosphorus contentswere determined in 3-month-old seedlings. Grayscale andcolour images were used to study root morphology andtopology, and to assess the relation between rootpigmentation and physiological activities. AM colonisationlead to a higher allocation of biomass to white andyellow parts of the root. Inorganic nitrogen uptakecapacity per unit root length and nitrogen content weregreatest in AM colonised plants grown under low nutrientconditions. A better match was found between plantnitrogen content and biomass accumulation, than betweenplant phosphorus content and biomass accumulation. It issuggested that the increase in nutrient uptake capacity ofAM colonised roots is dependent both on changes in rootmorphology and physiological uptake potential. Thisstudy contributes to an understanding of the role of AMfungi and root morphology in plant nutrient uptake andshows that AM colonisation improves the nitrogennutrition of plants, mainly when growing at low levelsof nutrients