Interphase nuclear structure and heterochromatin in Phaseolus plant species

Abstract

Interphase nuclear structure was studied in five Phaseolus plant species. All the species showed chromocentric nuclear organization in both meristematic and differentiated cells. The number of chromocenters appeared to be a species-specific character. Percentage heterochromatin values, as determined by using three different staining techniques, were higher in meristematic cells than those in differentiated cells. There was a close correspondence between percentage heterochromatin and amount of highly repetitive DNA implying a possible involvement of the latter in chromatin condensation.

Interphase nuclear structure and heterochromatin in Cicer species.

“…Percentage heterochromat in values in differentiated cells were considerably less than those in meristematic cells . NagI Such an observation was made in Phaseolus root tips by Patankar and Ranjekar (1984). Under replication of heterochromatin was also reported in Cucumis species during leaf and fruit differentiation (Pearson et al 1974).…”

“…Chromocentric nuclear organization was reported in Phaseolus species by Patankar and Ranjekar (1984). The chromocentres became more clear and distinct after disruption of euchromatin by HCl or Ba(OH)2 indicating their heterochromatic nature and the chromocentre numbers were easily countable.…”

“…These studies have indicated several interest ing features of the interphase nuclei (once thought to be resting nucleus) like non -random ar rangement of chromosomes, somatic association and specific orientation of chromosomes maintaining their telophasic configurations (Patankar and Ranjekar 1984) . Interphase nuclear organization of plants is species specific , however, it's determinants are not clearly known, al though the role of nuclear DNA content and repititive DNA sequences has been suggested (Lafontaine 1974, Nagl andFusenig 1979).…”

“…Among dicotyledons, interphase nuclear structure has been studied in Anemone (Marks and Schweizer 1974). However, recently interphase nuclear structure in five dicots (Joshi and Ranjekar 1982) and in five species of Phaseolus (Patankar and Ranjekar 1984) has been studied using the HCl -Giemsa technique.…”

Cytology of Vicia species II. Banding patterns and chromatin organization in Vicia atropurpurea Desf

“…The determination of the nuclear chromatin fractions with different condensation levels by cytophotometric analysis at different thresholds of optical density is used as an alternative approach to the banding method as used by Patankar & Ranjekar (1984b) for the determination of the heterochromatic fraction.…”