TITLE:
High Frequency Sporophytes Regeneration from the Spore Culture of the Endangered Aquatic Fern Isoetes coreana
AUTHORS:
Myung Jin Oh, Changkyun Kim, Hye Ryun Na, Hyunchur Shin, Jang R. Liu, Hong-Keun Choi, Suk Weon Kim
KEYWORDS:
Aquatic Fern; Isoetes coreana; Spore Culture; Sporophyte Regeneration
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.6A,
June
19,
2013
ABSTRACT: Using a mixed culture of megaspores and
microspores from I. coreana, we established high frequency sporophyte
regeneration system. After 20 days of culturing in MS basal medium, microscopic
examination showed significant morphological changes and the microspore released
numerous small vesicles into the culture medium. Megaspores also showed
dramatic morphological changes during its incubation time in culture. The spore
wall was cracked by the expansion of the megaspore (about 2 times increase in
diameter). Simultaneously, brown spots were observed on the surface of the megaspores.
The frequency of female gametophytes developing from immature megaspores
cultured in MS basal liquid medium (pH 7) supplemented with 1 mgl-1 GA3 was 46%. However, these female gametophytes derived from megaspore only culture
could not differentiate into sporophytes. The mixed culture of microspores and
megaspores resulted in successful sporophyte regeneration. The highest
frequency (12.3%) of green sporophyte regeneration from mixed spore culture
occurred when the cultures were maintained at 25℃ under cool-white fluorescent
light (40 μmol·m-2·s-1) with a 16 h
photoperiod. Regenerated sporophytes were transferred to a test tube containing
vermiculite and a sand mixture and left there until they had three leaves.
After root growth and the fifth leaf had emerged, more than 95% of the
regenerated sporophytes were successfully transferred to the soil and grown to
mature plants. The sporophyte regeneration system established in this study
could be successfully used for the restoration of the endangered aquatic
species, I. coreana.