Abstract
This study was carried out to develop a method for production of tetraploid Moodeungsan watermelon (Citrullus vulgaris cv. Moodeungsan, 2X=22). Anti-mitotic agents, colchicine (0.05, 0.1, 0.2, 0.5%) and oryzalin (5, 15, 30, 60 ${\mu}M$), were applied to the growing points of young seedlings, respectively. Various parameters including the growth at early stage, induction rate of tetraploids and morphological differences between diploids and tetraploids were investigated. When young seedlings were treated with 0.2% colchicine for 48 hours or 60 ${\mu}M$ oryzalin, more than 50% of the plants failed to produce shoots. The induction rate of tetraploids appeared highest from the seedlings treated with 0.2% colchicine for 12~24 hours as well as from those treated with 5~30 ${\mu}M$ oryzalin for 24 hours. When compared to diploids, tetraploids quite differed in various characteristics including the size and number of guard cell chloroplasts, the size of anther and pollen grains of male flowers, and shape of leaves. Flow-cytometric analysis showed that many of the apparent tetraploids were mixoploids. The number of seeds per fruit of the tetraploid was about one tenth of diploids, and many of them had no embryos.
본 연구는 무등산 수박 4배체의 효과적인 작성법을 구명하기 위하여 실시하였다. 2배체 고정종에 염색체 배가를 위해 방추사형성 억제 물질인 colchicine(0.05, 0.1, 0.2, 0.5%)과 oryzalin(5, 15, 30, 60mM)을 처리하여 초기 생육상태와 4배체 유기빈도, 4배체의 특성을 2배체와 비교하였다. 염색체 배가 약제 중 colchicine은 0.2%, 48시간 이상, oryzalin은 60mM 농도에서 처리하면 50% 이상의 개체에서 순멎이 현상이 나타났다. 4배체 발생율은 콜키친 0.2%, 12~24시간처리가, oryzalin은 5~30mM 농도에서 24시간 처리한 경우에 4배체가 많이 발견되었다. 4배체와 2배체 식물은 공변세포내 엽록체의 수, 기공의 크기, 수꽃크기, 화분크기, 모양 등으로 구분이 가능하였다. Flow-cytometry 분석결과 유기된 4배체의 상당수가 mixoploid인 것으로 나타났다. 4배체 과실에서 얻어진 종자는 2배체의 약 1/10의 종자가 있었으며 그중 소수만이 배를 함유하였다. 종자의 크기와 모양에 있어서도 2·4배체 간에차이가 있었다.