Pa. Mason et al., Mycorrhizal development and growth of inoculated Eucalyptus globulus (Labill.) seedlings in wet and dry conditions in the glasshouse, FOREST ECOL, 128(3), 2000, pp. 269-277
As Eucalyptus globulus (Labill.) seedlings are being widely outplanted to s
ites characterised by both high and low rainfall, this study describes the
effect of soil moisture availability on mycorrhizal development and growth
of seedlings inoculated with three different fungi. The information generat
ed by this study should enable the nurseryman to target which mycorrhizal f
ungi to select as suitable inoculants for dry and wet sites.
Mycorrhizal and non-mycorrhizal seedlings of E. globulus, grown under non-n
utrient limiting conditions, were subjected to two different watering regim
es from nine weeks after inoculation. During the following eight weeks, wee
kly measurements of stomatal conductance were made. All fruit bodies were c
ollected, as they were formed, and the plants were harvested at 17 weeks.
Of the three fungi used as inoculants, an isolate of Laccaria fraterna (Coo
ke and Mass.) Peg. formed the highest level of infection on seedlings that
were watered normally whereas, on seedlings that were water-stressed, Pisol
ithus tinctorius (Pers.) Coker and Couch (syn. P. arhizus (Pers.) Raus.) ac
hieved greatest mycorrhizal development. However, this isolate of L. frater
na sustained high levels of infection (>50%) on E. globulus seedlings in bo
th 'wet' and 'dry' regimes. Seedlings subjected to drought conditions posse
ssed significantly less stem and leaf biomass. Although there was a negativ
e correlation between mycorrhizal development and shoot growth on seedlings
watered normally, for those raised in the drier regime, benefits attributa
ble to mycorrhizal inoculation were detected. In particular, the stomatal c
onductances of inoculated plants, raised in the 'dry' regime, were found to
be greater than those of non-inoculated plants growing in the same conditi
ons. (C) 2000 Elsevier Science B.V. All rights reserved.