On the Presence of Para-Crystalline Formations in the Cytoplasm of a Maize Albino Mutant

Seeds of « Bagnolo » variety of maize, exposed to gamma radiation with a dose of 2.104r, gave rise to plants wich by self-fertilisation produced a X2-generation wich included: thoroughly green seedlings, albino seedlings which before maturity died, and of light-green or variegate seedlings, the latter interpretable as heterozigous (cfr. BERTONE 1964).For the present research, mutant albino seedlings obtained from seeds of heterozigous X2-plants, and control seedlings obtained from seeds of normal maize plants, were used.Using the electron microscope it was possible to observe in the mutant cytoplasm the presence of paracrystalline structures with a periodicity of about 120A. The paracrystals were not limited by membrane, were preferably localized close to the nucleus, and can be considered as protein crystals. These crystals were found in a mutant with altered plastid morphology, similar to those described previously for albina or xantha mutants. The accumulation of these crystals may be caused by a defect in the utilization of certain compounds by the abnormal chloroplasts.