Effects of ammonium and nitrate on encystment and growth of Scrippsiella trochoidea  

作　　者：Zhifu Wang Zhiming Yu Xiuxian Song Xihua Cao Yue Zhang 

机构地区：[1]Key Laboratory of Marine Ecology and Environmental Sciences,Institute of Oceanology, Chinese Academy of Sciences [2]University of Chinese Academy of Sciences

出　　处：《Chinese Science Bulletin》2014年第33期4491-4497,共7页

基　　金：supported by the Fund for Creative Research Groups by National Natural Science Foundation of China(41121064);‘‘Strategic Priority Research Program’’of the Chinese Academy of Sciences(XDA11020302);the National Natural Science Foundation of China(41276115);the National Basic Research Program of China(2010CB428706)

摘　　要：To avoid unfavorable environmental conditions, Scrippsiella trochoidea is capable of forming a resting cyst in the process of growth. In the present study,we investigated the effects of nitrate and ammonium on the growth and encystment of S. trochoidea. We incubated S.trochoidea in modified f/2 media without nitrogen and silicate in flasks. The flasks were divided into two groups.Nitrate was added as a nitrogen source in the first group,and ammonium was added in the second group. The concentrations of the nitrogen compounds were 0, 10, 30, 60,and 90 lmol/L. The results indicate that NO3--N favors cell growth, and the cultures with a higher concentration of NO3--N were ineffective at forming cysts. In contrast,NH4--N promoted cell growth and cyst formation. At similar concentrations as NO3--N, NH4--N had a toxic effect on cell growth and increased the cyst formation ratio.Thus, the NH4--N concentration is an important factor for controlling encystment. We believe that the impact of NH4--N in inducing cyst formation may be a useful feedback mechanism in ecological systems.To avoid unfavorable environmental condi- tions, Scrippsiella trochoidea is capable of forming a resting cyst in the process of growth. In the present study, we investigated the effects of nitrate and ammonium on the growth and encystment of S. trochoidea. We incubated S. trochoidea in modified f/2 media without nitrogen and silicate in flasks. The flasks were divided into two groups. Nitrate was added as a nitrogen source in the first group, and ammonium was added in the second group. The concentrations of the nitrogen compounds were 0, 10, 30, 60, and 90 μmol/L. The results indicate that NO3--N favors cell growth, and the cultures with a higher concentration of NO3--N were ineffective at forming cysts. In contrast, NH4＋-N promoted cell growth and cyst formation. At similar concentrations as NO3--N, NH4＋-N had a toxic effect on cell growth and increased the cyst formation ratio. Thus, the NH4＋-N concentration is an important factor for controlling encystment. We believe that the impact of NH4＋-N in inducing cyst formation may be a useful feedback mechanism in ecological systems.

关 键 词：锥状斯氏藻 细胞生长 铵态氮 硝态氮 包囊 硝酸溶液 氮化合物 毒性作用 

分 类 号：Q949.2[生物学—植物学]