Bo-Kook Jang1,2,3, Ju-Sung Cho1,2, Shin-Ho Kang4, Cheol Hee Lee5,6. 1. Division of Animal, Horticultural and Food Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea. 2. Brain Korea 21 Center for Bio-Health Industry, Chungbuk National University, Cheongju, 28644, Republic of Korea. 3. Research Center for the Development of Advanced Horticultural Technology, Chungbuk National University, Cheongju, 28644, Republic of Korea. 4. Faculty of Bio-Pharmaceutical Industry, Semyung University, Jecheon, 27136, Republic of Korea. 5. Division of Animal, Horticultural and Food Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea. leech@chungbuk.ac.kr. 6. Brain Korea 21 Center for Bio-Health Industry, Chungbuk National University, Cheongju, 28644, Republic of Korea. leech@chungbuk.ac.kr.
Abstract
BACKGROUND: Liquid suspension culture efficiently proliferates plant cells and can be applied to ferns because it rapidly increases the fresh weight of gametophytes. This study assessed gametophyte proliferation and sporophyte production of Pteridium aquilinum var. latiusculum using a suspension culture method. RESULTS: The growth curve linear phase of gametophyte cells was confirmed between 9 and 18 days of culture, and the subculture cycle was determined to be 2 weeks. A double-strength MS medium (fresh weight, 18.0 g) containing 2% sucrose and NH4+:NO3- (120 mM, 40:80) was found to be the optimal liquid medium. Gametophytes obtained after suspension culture for 18 days did not normally form sporophytes in an ex vitro soil environment. However, this issue was resolved after changing the culture type or extending the culture period to 6 weeks. A short suspension culture period increased the fresh weight of fragmented and homogenized gametophytes but yielded numerous relatively immature gametophytes (globular forms of branching gametophytes, BG). Furthermore, differences in gametophyte morphogenesis and development were indicated by changes in endogenous phytohormone content. BG with immature development exhibited high accumulation of zeatin, jasmonic acid, and salicylic acid, and relatively low levels of abscisic acid and indole-3-acetic acid. The immature development of gametophytes directly affected sporophyte formation. CONCLUSIONS: This study maximized the advantages of liquid suspension culture using eastern bracken gametophytes and provides data to resolve any associated issues, thus facilitating efficient bracken production.
BACKGROUND: Liquid suspension culture efficiently proliferates plant cells and can be applied to ferns because it rapidly increases the fresh weight of gametophytes. This study assessed gametophyte proliferation and sporophyte production of Pteridium aquilinum var. latiusculum using a suspension culture method. RESULTS: The growth curve linear phase of gametophyte cells was confirmed between 9 and 18 days of culture, and the subculture cycle was determined to be 2 weeks. A double-strength MS medium (fresh weight, 18.0 g) containing 2% sucrose and NH4+:NO3- (120 mM, 40:80) was found to be the optimal liquid medium. Gametophytes obtained after suspension culture for 18 days did not normally form sporophytes in an ex vitro soil environment. However, this issue was resolved after changing the culture type or extending the culture period to 6 weeks. A short suspension culture period increased the fresh weight of fragmented and homogenized gametophytes but yielded numerous relatively immature gametophytes (globular forms of branching gametophytes, BG). Furthermore, differences in gametophyte morphogenesis and development were indicated by changes in endogenous phytohormone content. BG with immature development exhibited high accumulation of zeatin, jasmonic acid, and salicylic acid, and relatively low levels of abscisic acid and indole-3-acetic acid. The immature development of gametophytes directly affected sporophyte formation. CONCLUSIONS: This study maximized the advantages of liquid suspension culture using eastern bracken gametophytes and provides data to resolve any associated issues, thus facilitating efficient bracken production.