Resumo

DIEZ GOMEZ, María Claudia; OSORIO VEGA, Nelson Walter  e  MORENO HURTADO, Flavio Humberto. EVALUATION OF THE UNIT MICORRIZAL OF ROMERÓN PINE (Nageia rospigliosii Pilger) UNDER CONTRASTING LIGHT CONDITIONS. Rev. Fac. Nac. Agron. Medellín [online]. 2008, vol.61, n.2, pp.4554-4563. ISSN 0304-2847.

Nageia rospigliosii Pilger is a tropical coniferous tree from highland Andean forests, which grows in phosphorous (P) deficient soils.  Under such conditions micorrhizae can perform an important function in plant nutrition.  This paper evaluates the mycorrhizal dependency and leaf P concentration in seedlings of this species inoculated with Glomus aggregatum under different levels of light intensity and phosphorus availability in soil solution using a split-plot experimental design.  Seedlings were grown under three levels of relative illumination (RI) in shade houses which resembled light conditions of understory with low light (2% RI), medium-sized canopy gaps or forest edges with medium RI (18% RI) and full sun exposure with high RI. After sterilization, soil received KH₂PO₄ to obtain three levels of P concentration in soil solution (0.002, 0.02 y 0.2 mg•L^-1).  Results showed that this species is "Moderately Dependant" on mycorrhizal association and that this condition was similar for plants growing under different light intensities.  Foliar P increased with the increase of P concentration in soil solution.  Inoculation with G. aggregatum significantly increased foliar content of P under low to moderate P in soil solution (0.002 and 0.02 mg•L^-1) but not under high P concentration (0.2 mg•L^-1).

Palavras-chave : Arbuscular mycorrhiza; mycorrhizal dependency; Podocarpaceae; Glomus aggregatum; Andean forest seedlings; phosphorous.

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