BORIE, FERNANDO, ROSA RUBIO, ISABEL MARTINEZ & CARLOS CASTILLO.
Universidad de La Frontera, Casilla 54-D, Fax 56.45.325440, Temuco, CHILE.
Aluminum phytotoxicity and restricted phosphorus availability are the main
constraints for plants growing in acidic Andisols. As some mechanisms involved
in Al-tolerance are similar to those which enhance P acquisition, the objective
of this work was to study root AM colonization and phosphatase activity (P-ase)
in two wheat cultivars differing in Al-tolerance and harvested at different
growth stages to identify the operative mechanisms. An Al-tolerant (Otto) and
an Al-sensitive (Pankul) wheat cultivar were grown in pots containing
sterilized acidic Andisol with and without treble super phosphate (TSP) and
inoculated or non-inoculated with Glomus etunicatum WV579AZ (Morton
& Bentivenga). Shoot and root growth, root AM colonization, root and soil
P-ase and root and shoot P contents were compared in plants harvested at
different growth stages. From the results obtained it can be concluded that: a)
both wheat cultivars were strongly mycorrhizal dependent; b) the highest
mycorrhizal root colonization was observed at anthesis in Pankul and at
maturity in the Otto cultivar; and was scarcely depressed with TSP; c) in both
cultivars the highest root P-ase was obtained before tillering and decreased
after, in contrast to AM colonization; d) P contents were highest at shooting
in Pankul and at anthesis in Otto.
Supported by FONDECYT 1950842 and IFS 426 Grants