Study of chromosomes, DNA amount, and in vitro growth in different species of Luzula

Abstract

Cells of six different species of Luzula were subjected to in vitro culture and examined for callus formation. The cells of calli from the different species were analyzed for variation in chromosome number. The cells of different species showed a differential response in culture with respect to callus growth. Chromosome number variation in vitro, including both hypo- and hyper-diploidy, was recorded in all species except L. pediformis and L. luzuloides. The chromosome fragments survived as a result of a nonlocalized centromere. With prolonged culture, normal diploid cells were frequent. The nuclear DNA content of cells of these species was also measured, both in vivo and in vitro. The DNA values ranged from 6.05 to 7.03 pg per 4C nucleus. No marked change in DNA value was noted in cells even with high chromosome numbers, thereby confirming their origin through fragmentation of chromosomes. In cells of callus, the DNA amount was observed to be higher than in normal cells, indicating fragmentation and duplication of individual chromosomes. Their importance in the origin of new genotypes has been indicated.Key words: Luzula spp., in vitro growth, chromosomes, nuclear DNA content.