Citogenetički efekat etilmetansulfonata u paprike

Abstract

Osušeno seme paprike je tretirano 1%, 2% i 3% rastvorom etil metan sulfonatom (EMS) u trajanju od 6, 8 i 12 sati, na temperaturi od 20°C i pH podešenom na 7.

Podaci o klijavosti i preživljavanju ukazali su na prilično smanjenje vitalnosti sa povećanjem koncentracije EMS-a i produženim tretmanom. Preživljavanje se smanjivalo za 20% sa produžavanjem 1% EMS tretmana sa 6 sati na 12 sati, a za 34% sa povećanjem koncentracije EMS sa 1% na 3% (u 8-časovnom tretmanu). Citološke analize preživelih M1 biljaka dobijenih iz semena tretiranih sa 1% EMS, pokazale su da je oko 9% ćelija u metafazi I sadržalo jedan neorijentisani bivalent, što ukazuje na blagu abnormalnost centromera. Ovo je bila jedina hromozomska aberacija primećena posle 1% EMS tretmana. Posle 2% EMS tretmana neorijentacija bivalenta je porasla na 13,3% i 6,6% kod ćelija u anafazi i koje su sadržale hromatinske mostove. Učestalost hromozomskih aberacija su značajno povećane 3% EMS tretmanom. Najčešći tipovi hromozomskih aberacija su bile pseudo-izohromozomi (25%), univalentni u metafazi I (8%), dicentrični hromatinski mostovi u anafazi I (9,26%), zaostali i mikronukleusi u telofazi I i II. Rezultati našeg istraživanja takođe potvrđuju da je centromerni region najpodložniji efektima EMS. Povreda centromera kod paprike izazvana je 1% EMS, dok su ozbiljnije strukturne hromozomske aberacije indukovane tek 2% i 3% EMS. Takođe, na osnovu ovih činjenica smo zaključili da su hromozomi paprike manje podložni mutagenom dejstvu EMS od hromozoma nekih drugih biljnih vrsta.

Air dry seed of pepper was treated with 1%, 2% and 3% ethyl methane sulfonate (EMS) for duration of 6, 8 and 12 hours, at a temperature of 20°C and pH adjusted to 7.

Data on the germinability and survival show a rather regular decrease of vitality with increased concentration of EMS and prolonged treatment. The survival is reduced by 20% when treatment with 1%, EMS is extended from 6 hours to 12 hours, and 34% by the increase of concentration of EMS from 1% to 31% (in the 8-hour treatment).

Cytologic analyses of survived M1-plants produced from seeds treated with 1% EMS, revealed that about 9% of metaphase I cells contained one non-oriented bivalent, an indication of a slight centromere abnormality. This was the only chromosome aberration observed after 1% EMS treatment- After 2% EMS treatment non-orientation of bivalents increased to 13.3% and 6.6% anaphase, I cells contained chromatin bridges.

The frequency of chromosome aberrations was increased greatly by the 3% EMS treatment. The most frequent kinds of chromosome aberrations we-re pseudo-isochromosomes (25%), univalent in metaphase I (8%), dicentric chromatin bridges in anaphase I (9,26%), laggards and micronuclei in telophase I and II.

The results of our research confirm also that the centromere region is the most susceptible to the effects of EMS. Centromere injury in pepper was induced by 1% EMS, whereas more serious structural chromosome aberrations were induced only after 2% and 3% EMS. Also, on the basis of these facts we have concluded that the chromosomes of pepper are less susceptible than the chromosomes of some other plant species to the mutagenic effect of EMS.