Studies on the development of orchid microspores in vitro culture of pollinium

• Main Authors: Yi-Ting Cheng, 鄭伊婷
• Other Authors: Hu-Sheng Lu
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/70246372502217437548

碩士 === 國立臺灣大學 === 農藝學研究所 === 100 === Homozygous double haploids (DHs) generated from haploid plants through chromosome doubling in anther culture, are widely used in crop breeding programs. It has been useful in such research areas as gene mapping, genetic transformation, mutation studies, and cytogenetic studies. In order to investigate effects of different factors on induction of pollinia and development of microspores, and to establish primary protocols of anther culture of orchids, pollinia from two Taiwan native species orchids Phalaenopsis aphrodite sub. formosana Shimadzu, Phalaenopsis equestris (Schauer) Reichb. f. and two commercial cultivars Tolumnia hybrid, Phalaenopsis spp. hybrid ‘Manshanhung’ were used as materials in this thesis. The percentages of induction were higher when pollinia from the ca. 6 mm length of buds of P. equestris (Schauer) Reichb. f. were treated with 50 ppm GA solution for one day and cultured on the medium with 6% sucrose in the dark. The results indicated that buds of Tolumnia hybrid about 6-7 mm in length was appropriate for culture, and the microspores at that bud size were at uninucleate to binucleate stage. Besides, the best response was obtained when medium containing 6% sucrose but pollinia can’t differentiate in the 20% sucrose medium. Pollinia from premature buds of Phalaenopsis aphrodite sub. formosana and from open flowers of four orchids did not have any reaction in all treatments. There are a lot of crystalloid needle-like structures on the surface of differentiated pollinia and long tube-like structures could be observed on microspores. Substances that hold microspores together disappeared in some case, so microspores might be on top of another or away from others. Some microspores divided repeatedly and resulted in syncytia of more than 4 nuclei. The color of pollinia turned white and the needle-like structure became shortened or disappeared when the pollinia were subcultured in the differentiation medium on MS salts, 3% sucrose, 1 mg/l NAA, 4 mg/l kinetin, 0.2% (w/v) charcoal, and 0.8% (w/v) agar. Shoots and roots could not be generated in the tested differentiation medium.