Algae. 1986; 1(1): 145-156.

Field and Cultural Observations of Polysiphonia decumbens Segi

Kyung-Sook Byun, Jae-Won Kang

Department of aquaculture, Pohang Junior College, Department of Marine Biology, National Fisheries University of Pusan

Polysiphonia decumbens Segi collected at Yonghodong and Haeundae in Pusan was cultured int he laboratory for observation of the stability of some taxonomic characters. The plants were cultured at 22℃ with a photoperiod of 16:8 LD at light intensity of 1,200-1,500 lux. PES media were used for all cultures. this species basically showed a triphasic alternation of generations in life history, but specialized asexual propagules were unexpectedly observed. P. decumbens from the both localities produced specialized asexual propagules, developmentally and morphologically resembling spermatangial branches bur appearing on both the male and female plants. These propagules were equipped with a functional rhizoid and apical part. Compared with field and culture plants it was found that such taxonomic characters as the number of pericentral cells, the presence of cortical cells and the origin of rhizoids showed no obvious variation. However, the shape and position of rhizoids, the occurrence frequency of trichoblast and the origin of spermatangial branch showed some variation. Therefor, these characters are not suitable to adopt for taxonomic characters.

Keywords : Asexual propagule, culture study, Polysiphonia decumbens