RINCON, ANA, ISABEL F.ALVAREZ, JAVIER PARLADÉ & JOAN PERA.
Institut de Recerca i Tecnologia Agroalimentaries. Dept. Patologia Vegetal. Ctra. de Cabrils s/n E-08348 Cabrils (Barcelona) SPAIN.
Sporocarps of Rhizopogon luteolus Fr. & Nordh. and R.
roseolus (Corda ex Sturm) Fr. have been regularly collected in
nurseries, mixed Pinus pinea L. stands and other conifer forests in
Catalonia (northeastern Spain). The capability of both fungal species to form
ectomycorrhizas with containerized P. pinea seedlings has been tested
using spore suspensions. In order to optimize the nursery production of
ectomycorrhizal P. pinea seedlings inoculated with R. luteolus
and R. roseolus, two types of substrates mixtures currently used in
nurseries: peat-vermiculite (1:1, v:v), pH 5.5 (P-V), and peat-composted pine
bark (1:1, v:v), pH 7.7 (P-CPB), have been tested. The percentages of
mycorrhizal short roots obtained were significantly lower in P-CPB compared to
those obtained in P-V substrate. Moreover, plants grown in P-CPB substrate
showed chlorosis symptoms probably due to deficiencies in the foliar content of
Mg and Mn. Compared to non inoculated plants, the inoculation with R.
luteolus and R. roseolus produced a significant increment of N and P
contents.
In spring of 1996 and 1997, P. pinea seedlings, non inoculated and
inoculated with R. luteolus and R. roseolus, were outplanted in
four different locations of Barcelona and Girona (Spain). Field data are still
preliminary but differences in mortality, related to the substrate used during
nursery production and the inoculation with Rhizopogon sp., has been
observed during the first year. In some sites, plants inoculated with R.
roseolus grew better than non inoculated plants. Growth and survival of
outplanted seedlings must be monitored at least during five years in order to
detect long-term effects.