DIAZ, GISELA1 & MARIO HONRUBIA.1
1Departamento de Biología Vegetal (Botánica), Facultad de Biología, Universidad de Murcia, Campus de Espinardo, 30100, Murcia, SPAIN.
Several experiments have been carried out on containerized P. halepensis
seedlings with the aim of improving controlled mycorrhizal infection in
nursery conditions.
Cultural device had a great influence on the succes on obtaining mycorrhizal
plants. The use of an adequate substrate, a container that favour inoculum
application and a sowing and transplanting method not damaging for the root
system and mycelium significantly improved mycorrhizal colonization.
The age of seedlings (time period required for the development of secondary
roots suitable for mycorrhization) should be combined with the time of
inoculation to assure the mycelium survival. The best results were obtained
when inoculation was performed before the hot season on 3-4 month old
seedlings.
A screening with different types of inocula (peat/vermiculite, alginate beads,
mycelial slurries) and application doses showed that for P.tinctorius
the most effective inoculum was peat/vermiculite, being sporal inoculum
also acceptable. Around 40% mycorrhizal plants for Suillus sp.
were obtained with peat/vermiculite whereas alginate beads was very effective
for S. mediterraneensis. By the contrary, the use of mycelial slurries
gave less than 20% mycorrhizal plants.
Three different fertilization regimes (30.8, 15.4 and 6.6 mg N/plant) were
applied during the phase of ectomycorrhizal formation. A negative effect of the
fertilization commonly used in nurseries with Aleppo pine was not observed,
suggesting the compatibility of fertilization and mycorrhiza development.The
lowest fertilization seemed to diminish the succes of mycorrhization, as well
as plant growth. However, an amelioration of mineral nutrition on mycorrhizal
seedlings was noted in the three treatments.