Micropropagated plantlets of cv. Mulata and cv. Galhosa growing in pots,
after acclimatization in the glasshouse and growth for several months under
natural conditions, were transferred to a field trial. Carob seedlings of ‘Mulata’
were also transferred under the same conditions. The field trial has been
established with 100% of success in micropropagated plants and 97% in seedlings.
Three months after transfer to the field, plants showed good growth but
micropropagated plants of ‘Mulata’ exhibited more vigour than ‘Galhosa’ and
than seedlings, with the greatest number of branches and a larger length increase
in the main stem. Before transference to the field, net photosynthetic rates (PN),
water use efficiency (PN/gs) and quantum yield of PSII (fPSII) of the potted plants
were higher in seedlings than in micropropagated plants. Three months after
transplantation all gas exchange parameters were improved for all types of plants,
particularly net photosynthetic rate, and no significant differences were observed
between plants either micropropagated or seedlings. On the other hand, fPSII
decreased significantly in seedlings. The results suggest that the pre-acclimation, in
pots, to external environmental conditions might have improved field survival,
plant vigour and enhanced the endurance to adverse conditions of
micropropagated carob trees