Abstract
The seeds of naturally growing Heteropappus hispidus (Thunb.) were treated by nine different doses (0, 10, 20, 40, 80, 120, 160, 200, 300, 400 Gy) of gamma rays to investigate their germination rate and to quantity the characteristics of their germinated plants as like as leaf appearance and length, the formation rate of anthocyanin color in stem 30 days after germination, the formation rate of rosette leaf and multi-shoot, the flowering and seed-bearing, and shoot length. The germination rate at least up to 120Gy was not greatly affected but was rapidly decreased at over 160Gy. It seemed that lethal dose ($LD_{50}$) of germination was 160Gy. The leaf appearance and growth was also inhibited, but the formation rate of anthocyanin color in the flower stem was enhanced up to 30% with dose. The rosette plants were observed in plants irradiated with higher than 40Gy. Multi-shoots were developed over 80Gy. For a short shoot length and bundle of thin stem, it was considered that they can be selected as the potential pot flower plants, through genetic fixation. In particular, it was suggested that the formation of anthocyanin color in flower stem, rosette and multi-shoot plants induced by the high dose of gamma rays could be utilized as the morphological markers for the mutant selection of Heteropappus hispidus (Thunb.).
제주도에서 자생하는 갯쑥부쟁이(Heteropappus hispidus (Thunb.))에 감마선을 10, 20, 40, 80, 120, 160, 200, 300, 400 Gy 수준으로 나누어서 조사한 뒤 발아율 및 발아 30일 후의 본엽 출현율, $LD_{50}$, 본엽길이, 줄기부분의 안토시아닌 색소 형성 유무, 생육 60일 후의 로젯형 엽, multi-shoot 형성율, 초장, 개화 결실률 등의 주요 양적형질들을 생존개체를 대상으로 실시하였다. 120Gy 까지의 발아율은 88.5%로 대조구와 큰 차이를 보이지 않았으나 160Gy 이상에서부터는 급격히 감소하여 치사선량($LD_{50}$)은 160 Gy 범위 정도였다. 또한, 본엽 출현율과 그 길이는 조사선량이 높아질수록 억제되었다. 안토시아닌 색소 형성은 조사선량이 높을수록 대조구 2%에서 30%로 높아졌으며 로젯형도 고선량 처리구에서 발생하였다. Multi-shooting은 80Gy 이상일 때부터 나타났으며 multi-shooting을 형성하는 개체들은 초장은 짧고 줄기는 가늘게 다발형으로 자라는 특성이 있어서 만일 형질이 고정된다면 화분 관상용 개체로 선발하기에 적합하였다. 특히, 조사선량이 증가됨에 따라서 안토시아닌 색소 형성, 로젯형 개체, multi-shoot등의 개체가 많이 출현되었는데 이는 돌연변이 유기의 선발지표가 될 수 있을 것으로 보인다.
