The balance of autotrophy and heterotrophy during mixotrophic growth of Karlodinium micrum (Dinophyceae)
The balance of autotrophy and heterotrophy during mixotrophic growth of Karlodinium micrum (Dinophyceae)
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DOI：
10.1093/plankt/fbl007
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发表时间：
2006-08-01
影响因子：
2.1
通讯作者：
Harding, Lawrence W., Jr.
中科院分区：
文献类型：
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作者：
Adolf, Jason E.;Stoecker, Dmine K.;Harding, Lawrence W., Jr.
我们研究了 Karlodinium micrum (leadbeter et Dodge) Larsen (Dinophyceae) 在猎物 Storeatula Major (Cryptophyceae) 上混合营养生长过程中的自养和异养 C 代谢。我们的目标是确定自养和异养的平衡，以支持微型 K 的混合营养生长。无机 C-14 和 C-14 标记猎物的同化分别用于分离通过自养和异养获得的 C 的数量和质量（即脂质、多糖和蛋白质）。混合营养型微型钾的生长速率（μ）为0.52-0.75 div。 (.) 天(-1)，等于或大于K. microrum 的最大自养生长速率(0.55 div.(.) 天(-))。在混合营养生长期间，自养占总碳吸收的 27-69%。混合营养生长期间的细胞光合性能（PPcell pg C cell(-1) (.) day(-1)）比 K micrum 自养生长期间低 24-52 %。与自养型 K. micrum 相比，混合营养型 K. micrum 吸收的光合产物减少 16%，而蛋白质是来自摄入猎物 C 的主要净同化产物 (52%)。基于自养和异养 C 来源的混合营养培养物的生长效率 (% GE) 平均为 36 +/- 2.9%，略低于典型的 40-50% GE。 纯自养微型 K. micrum，但与异养喂养相关的较高 C ginns 足以补偿混合营养 K. micrum 中 %GE 的下降。我们得出的结论是，尽管光合作用继续以较低的速率进行，但微型 K 的混合营养生长以异养代谢为主。这与以混合营养生长的 K. micrum 为主的浮游生物群向二次生产的转变是一致的。
We studied autotrophic and heterotrophic C metabolism during mixotrophic growth of Karlodinium micrum (leadbeter et Dodge) Larsen (Dinophyceae) on prey Storeatula major (Cryptophyceae). Our goal was to determine the balance of autotrophy and heterotrophy that supports mixotrophic growth in K micrum. Assimilation of inorganic C-14 and C-14-labeled prey was used to separate the quantify and quality, (i.e., lipid, polysaccharide and protein) of C obtained by autotrophy and heterotrophy, respectively. Growth rates (mu) of mixotrophic K micrum were 0.52-0.75 div. (.) day(-1), equal to or greater than the maximum autotrophic growth rate (0.55 div. (.) day(-)) of K. micrum. Autotrophy represented 27-69% of gross C uptake during mixotrophic growth. Cellular photosynthetic performance (PPcell pg C cell(-1) (.) day(-1)) was 24-52 % lower during mixotrophic growth than during autotrophic growth of K micrum. Mixotrophic K micrum assimilated 16% less photosynthate as protein compared to autotrophic K. micrum, while protein was the major net assimilation product (52 %) from ingested prey C. Growth efficiency (% GE) of mixotrophic cultures, based on both autotrophic and heterotrophic C sources, averaged 36 +/- 2.9%, slightly lower than the 40-50% GE typical of purey autotrophic K. micrum, but higher C ginns associated with heterotrophic feeding more than compensated for the decrease in %GE in mixotrophic K. micrum. We conclude that mixotrophic growth of K micrum is dominated by heterotrophic metabolism, although photosynthesis continues at a lowered rate. This is consistent with a shift toward secondary production in plankton assemblages dominated by mixotrophically growing K. micrum.