TITLE	Hyposaline effect on polyamine accumulation in Ulva fasciata (Ulvales, Chlorophyta)
AUTHOR	Tse-Min Lee Institute of Marine Biology, National Sun Yat-sen University, Kaohsiung, Taiwan 80424, Republic of China Ming-Hwa Chen Institute of Marine Biology, National Sun Yat-sen University, Kaohsiung, Taiwan 80424, Republic of China
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ABSTRACT	This study was conducted to investigate changes of free polyamine levels in response to hyposaline stress in Ulva fasciata Delile. Free putrescine, spermidine, and spermine are present in this alga. As salinity decreased from 30‰ to 5‰, specific growth rate (%/d), TTC reduction activity, net photosynthetic O2 evolution rate and chlorophyll levels decreased. Plants grown at 5‰ bleached except the basal part near rhizoidal portion. Free putrescine maintained at a constant level at salinity over the range of 10~30‰ and increased three fold following 5‰ treatment. Free spermidine also increased when salinity fell below 15‰. In plants grown at 5‰, free putrescine and spermidine accumulation in the basal part was less than in the remaining part. Free spermine levels increased as salinity decreased from 30‰ to 10‰, but dropped sharply at 5‰. Both a-difluoromethylarginine (0.2 mM) and D-arginine (1 mM), inhibitors of arginine decarboxylase (EC 4.1.1.19), and also both a-difluoromethylornithine (0.2 mM) and a-methylornithine (0.2 mM), inhibitors of ornithine decarboxylase (EC 4.1.1.17), inhibited the 5‰-induced free putrescine accumulation. Overall, the present results suggest that an extreme hyposaline condition (5‰) induced a significant accumulation of free putrescine and spermidine in U. fasciata and that ADC and ODC each contributed to free putrescine accumulation. The relationships between accumulated putrescine and hyposaline injury are discussed.
KEYWORD	Hyposaline stress; Putrescine; Spermidine; Spermine; Ulva fasciata;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 39 Number 3 July 1998, page 167-174, 8 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China