To establish a mass micropropagation procedure for Cephalotus follicularis, the effects of varying the strengths of solid Murashige and Skoog (MS) medium were investigated using subcultured shoot explants. After a 60-day primary culture from root mass, the regenerated shoot explants were subcultured every 60 days in solid MS medium. To facilitate shoot proliferation, liquid MS medium was applied with or without exogenous auxin and cytokinin. Our results demonstrate that shoot proliferation and survival of C. follicularis is most effective in modified MS (MMS) medium containing one-fifth or one-tenth strength macronutrients and full-strength micronutrients. Successful shoot proliferation and development of C. follicularis explants were obtained in one-fifth or one-tenth modified liquid MS medium without auxin and cytokinin or with addition of 5 μM indole 3-acetic acid/1 μM N6-benzyladenine for 45 days. The liquid medium consistently produced more explants than the solid medium and shortened the culturing time. Plantlets cultured in hormone-free one-fifth MMS medium developed greater root systems. Using the liquid culture we established, vigorous plants with extensive roots were obtained within 4 months. Plant survival in the greenhouse reached 100%.
Chia-Yun Ko, Tsai-Yun Lin, Chin-Wen Ho, and Jei-Fu Shaw
Ching-San Kuan, Chih-Wen Yu, Mei-Li Lin, Hsin-Tszu Hsu, Duane P. Bartholomew, and Chin-Ho Lin
Natural flowering of pineapple is a serious problem for commercial growers of pineapple because it disrupts fruiting schedules, decreases harvesting efficiency and increases costs, and may reduce the percentage of marketable fruit. Aviglycine ([S]-trans-2-amino-4-(2 aminoethoxy)-3-butenoic acid hydrochloride), an inhibitor of ethylene biosynthesis, was applied as a foliar spray to evaluate its potential to prevent natural flowering in 1-year-old `Tainon 18' pineapple. Two experiments were conducted between 10 Oct. and 10 Apr. during the 2001-02 and 2002-03 production seasons. For the 2001-02 season, single or double applications of aviglycine at 100 mg L-1 had no significant effect on natural flowering. A double application of aviglycine at 500 mg L-1 first applied on 9 Nov. reduced flowering from 95.0% in the control to 51.3% when evaluated on 25 Feb. 2002. In the 2002-03 production season, triple applications of aviglycine applied at 20-day intervals beginning on 10 Nov. 2002 significantly reduced natural flowering when evaluated on 28 Mar. 2003. There was 95.8% flowering in the control, 64.6% with 250 and 375 mg L-1 aviglycine, and 50% with 500 mg L-1 aviglycine. Aviglycine has the potential to partially control precocious flowering of pineapple, which will reduce crop losses associated with such flowering.