Biochemical studies with long term propagated asparagus callus of different organogenic competence
1990
Reuther, G.
From male (xy), supermale (yy) and female (xx) asparagus genotypes long-term callus cultures for more than 10 years have been established on agar solidified media. Lines consisting of completely dedifferentiated callus and such with high morphogenic competence were obtained by means of medium variations and selection. Cytophotometric measurements of the nuclear DNA of callus cells showed, that morphogenic callus has maintained preferently a diploid status and non-morphogenic callus was composed with diploid and polyploid cells. These two callus types have been used for comparative biochemical studies. An accumulation of protein bodies in the vacuole has been identified histochemically in both callus lines. The total protein content was higher in dedifferentiated callus. With polyacrylamide gel electrophoresis protein fractions in the position of storage proteins of seed extracts could be analysed. It is concluded, that protein deposition in callus is an important step of differentiation. The higher protein content of non-morphogenic callus indicates, that the ability for protein degradation for the formation of meristematic cells is limited. The sucrose content in dedifferentiated callus was in average 3-4 times higher than in organogenic callus, monomolecular carbohydrates revealed no significant differences. In storage organs of the field grown plants and in callus as well only fructan as reserved polysaccharide was found.
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