Influence of Shading and Gibberellic Acid on Growth and Sex of the Prothallia of Ceratopteris Thalictroides

10.6165/tai.1967.13.179

Su-Hwa Tsai Chiang；You-Long Chiang

TAIWANIA

13卷1期（1967 / 12 / 01）

179 - 193

英文

The growth of prothallia of Ceratopteris thalictroides in area was seriously restricted under the full intensity of sun light in the greenhouse. By shading, however, the growth was improved. In the early period of their growth, the growth was better under 1/8-1/4 sun light. As the prothallia grew older, the better growth was made under 1/2 sun light. It is thought that these results are related to the ”smallness” of the prothallium; the prothallium has to be small in order to get a suitable shading with case in a small hollow of the ground. The best growth was made when the prothallia were placed in continuous daylight fluorescent light in culture room. All concentrations of gibberellic acid (GA) ranging from 0.01 to 100 ppm inhibited the growth of prothallia during the early stage of their growth under all intensities of sun light. As the prothallia grew older, the lower concentrations (e. g., 0.01 ppm) became effective to promote the growth of prothallia which showed less growth under weak sun light. It thus appears that the lower concentrations of GA are effective to reverse the growth limitation imposed by the lower intensities of sun light. The effect of GA and light conditions on sexuality was indirect; primarily, GA and light conditions affected greatly on growth. More sex organs were formed on those prothallia which showed better growth in area. Doth unisexual and bisexual prothallia were obtained in the present study. It is suggested that a large heterogeneity sexuality in this fern is presumably related to antheridium-inducing substances. The larger prothallia with antheridia less than five were always found forming the sporophyte. On rare occasions, two sporophytes were developed from two different archegonia on the same prothallium.