CHANGES IN LEAF MORPHOLOGY AND ANATOMY OF IN VITRO-CULTURED CHESTNUT PLANTLETS DURING ACCLIMATIZATION

The effect of acclimatization of in vitro-cultured chestnut hybrid plantlets (Castanea sativa x C. crenata) was studied by comparing leaves formed in vitro and retained after transplantation with those formed ex vitro during acclimatization under two light intensities (150 and 250 μmol m^-2 s^-1), and with mature leaves of field-grown plants.
Marked morphological and anatomical differences were observed.
The leaves of the in vitro plantlets had thin narrow blades with little mesophyll differentiation.
During hardening, changes occurred in the persistent and in new leaves.
The latter showed a significant increase in thickness, a palisade parenchyma with two or more cell layers, vascular and support tissues differentiated in the midrib veins.
Stomatal frequency was reduced and was in leaves formed at the end of acclimatization not significantly different from field-grown leaves.
Scanning electron microscopy showed in in vitro leaves stomata protruding above the epidermis level, with circular and irregularly shaped guard cells while leaves from acclimatised plantlets had ellipsoid and depressed stomata, similar to field-grown ones.
No significant differences were found as a consequence of light level.

XXV International Horticultural Congress, Part 10: Application of Biotechnology and Molecular Biology and Breeding – In Vitro Culture.

J.C. Gonçalves, G. Diogo, M.T. Coelho, S. Amâncio

acclimatization, chestnut, leaf anatomy, leaf morphology, stomata

https://doi.org/10.17660/ActaHortic.2000.520.19