Abstract

Cotyledonary and hypocotyl explants of melon seedlings were cultured on Murashige and Skoog's (MS) medium supplemented with various concentrations of 2,4-Dichlorophenoxyacetic acid (2,4-D) and benzyladenine (B.A).Up to 22% of cotyledonary explants and 7%, of hypocotyl explants, respectively: Produced somatic embryos through intervening two types of calli: bright yellow compact (BYC) callus and pale-yellow compact (PYC) callus. BYC callus was capable of producing somatic embryos at initial culture, but it became necrotic as subrulhues proceeded. In contrast UC callus was incapable of producing somatic embryos during initial culture (first 6 weeks), but it became bright-yellow friable (BYF) callus with forming a few globular embryos after 2 months of subculture, indicating that the callus turned embryogenic. The embryogenic capacity of BYF maintained for over one year when the callus was sucultured at 4-week interval. Upon transfer onto MS basal medium the callus gave rise to numerous somatic embryos and subsequently converted to plantlets. Plantlets were transplanted to potting soil and grown to maturity in the phyotron.

멜론의 배발생 캘러스의 유도와 식물체 재분화 시스템을 확립하기 위해서 자엽과 배축의 절편을 여러 농도의 2,4-D 와 BA가 첨가된 MS 기본배지에 치상하여 관찰한 결과, 초기배양에서는 4 mg/L 2,4-D와 1 mg/L BA 그리고 2 mg/L 2,4-D+O.1 mg/L BA가 첨가된 배지에서 연한 노란색의 배발생 캘러스가 형성되었고, 위의 조건에서 형성된 캘러스로부터 배발생 캘러스는 0.5와 1 mg/L 2,4-D가 첨가된 동일배지에서 약 75%가 형성되었다. 그리고 생장조절제를 첨가하지 않은 기본배지에서 대부분의 체세포배는 식물체로 재분화되었으며, 두개의 자엽을 갖춘 정상적인 체세포배보다 비정상적인 나팔형의 자엽을 가진 것이 3배 높은 빈도로 나타났다. 이러한 체세포배들은 MS 기본배지에서 식물체로 발아되었으며 생육상에서 생장하여 견실한 열매를 맺었다.

Keywords

• cotyledonary explants;
• embryogenic callus;
• hypocotyl explants