Selma Tabur

Protective roles of exogenous polyamines on chromosomal aberrations in Hordeum vulgare exposed to salinity

The effects of exogenous polyamines (PAs): spermine (Spm), spermidine (Spd), cadaverine (Cad) and putrescine (Put) on mitotic activity and chromosomal aberrations in root meristem cells of Hordeum vulgare L. (barley) seeds exposed to salinity were analyzed. The PAs significantly inhibited cell division in distilled water. Furthermore, most of these PAs (except for Spd) caused a significant increase in the frequency of chromosomal aberrations as compared to control group. Seeds treated with Put caused the highest percentage of mitotic abnormalities in total. The negative effect of salinity on mitotic index and the frequency of chromosomal aberrations increased with increasing salt concentration. PAs studied could not be successful in ameliorating of the negative effect of salinity on mitotic activity. Particularly, exposure to Cad and 0.40 M NaCl caused a complete block of cell division in total. However, most of the PA studied showed a perfectly performance in alleviating the detrimental effects of increasing salinity on chromosomal aberrations.

New or rare data on chromosome numbers and karyomorphology of some taxa in the subgenus Seriphidium (Bess.) Rouy. (Artemisia, Asteraceae) in Turkey

Subgenus Seriphidium is one of the least karyologically studied groups in genus Artemisia. In this work, chromosome number and karyotypes of six taxa belonging to Seriphidium subgenus of genus Artemisia were investigated as detailed. Both chromosome number and karyological data of all taxa studied here were the first records from Turkey. Two of the taxa are new records to science (A. spicigera K. Koch. var. vanensis Kursat & Civelek var. nova and A. taurica Willd. var. pendulosa Kursat & Civelek var. nova) and another is a new record for the flora of Turkey (A. sieberi Bess. subsp. sieberi). All of the taxa studied except for A. spicigera K. Koch. var. spicigera were polyploid. Hypo-aneuploidy was observed in one taxon, A. santonicum L. subsp. santonicum with chromosome number 2n = 6x = 52. In addition, the simultaneous existence of B chromosome and aneusomy was recorded for A. taurica Willd. var. taurica, 2n = 4x = 36 + 0, 4B; 37 + 3, 4B.