Mixotrophy in Gyrodinium galatheanum (Dinophyceae):: Grazing responses to light intensity and inorganic nutrients
Mixotrophy in Gyrodinium galatheanum (Dinophyceae):: Grazing responses to light intensity and inorganic nutrients
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DOI：
10.1046/j.1529-8817.2000.98076.x
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发表时间：
2000-02-01
影响因子：
2.9
通讯作者：
Coats, DW
中科院分区：
文献类型：
--
作者：
Li, AS;Stoecker, DK;Coats, DW
本文介绍了河口甲藻 Gyrodinium galatheanum (Braarud) Taylor 混合营养的现场和实验室研究结果，我们测试了这种主要光合生物在面临次优光照和/或营养环境时变得吞噬营养的假设，在切萨皮克湾，该物种以隐植物为食的发生率与猎物密度以及硝酸盐和亚硝酸盐的浓度呈正相关，但呈负相关深度、盐度和磷酸盐浓度。自然组合和培养物中的取食量随光照强度呈双曲线增加，G. galatheanum 存在的站点溶解无机 P 和 N 的化学计量比 (DIP:DIN) 远低于最佳生长 P:N (1:10)，取食发生率与 DIP 与 DIN 的比例呈负相关，表明 P 限制可能会诱导取食。添加硝酸盐，或同时添加硝酸盐和磷酸盐，抑制自然群体中的摄食，表明氮限制也可能诱导摄食，通过培养的 G、galatheanum 摄入隐植物，Storeatula Major，在硝酸盐或磷酸盐或两者都低的培养基中含量较高，但在营养丰富的培养物中发生中等摄食率。当细胞在具有不同浓度的硝酸盐和磷酸盐的培养基中生长时，氮缺乏导致更大的细胞氮和 Chi a 损失缺磷比缺磷更能刺激摄食，氮和磷缺乏，或者 P:N 比例偏离 1:10 较大，都会导致细胞碳含量增加，摄食倾向增加。我们的结果表明，饲喂 G、galatheanum 在一定程度上是补充光合碳同化所需的主要营养物质（N 和 P）的策略。饲喂 G、galatheanum 也可能是补充 C 的策略新陈代谢或获取微量有机生长因子，因为在营养丰富的培养物中会发生摄食，尽管速度较低。
This paper presents results of field and laboratory studies on mixotrophy in the estuarine dinoflagellate Gyrodinium galatheanum (Braarud) Taylor, We tested the hypotheses that this primarily photosynthetic organism becomes phagotrophic when faced with suboptimal light and/or nutrient environments, In Chesapeake Bay, incidence of feeding of this species on cryptophytes is positively correlated with prey density and concentrations of nitrate and nitrite, but negatively correlated with depth, salinity, and phosphate concentration. Feeding in natural assemblages and cultures increased hyperbolically with light intensity, The stoichiometric proportions of dissolved inorganic P and N (DIP:DIN) at the stations where G. galatheanum was present were far below the optimal growth P:N (1:10), Incidence of feeding was negatively related to the ratio of DIP to DIN, suggesting that P limitation may have induced feeding. Addition of nitrate, or addition of both nitrate and phosphate, inhibited feeding in a natural population, indicating that N limitation may also induce feeding, Ingestion of the cryptophyte, Storeatula major, by cultured G, galatheanum was higher in media low in nitrate or phosphate or both, but moderate rates of feeding occurred in nutrient-replete cultures, When cells were grown in media with varying concentrations of nitrate and phosphate, N deficiency resulted in greater cellular N and Chi a losses than did P deficiency, but P deficiency stimulated feeding more than N deficiency, Both N and P deficiency, or P:N ratios that deviated greatly from 1:10, result in an increase of cellular carbon content and an increase in propensity to feed, Our results suggest that feeding in G, galatheanum is partly a strategy for supplementing major nutrients (N and P) that are needed for photosynthetic carbon assimilation, Feeding in G, galatheanum may also be a strategy for supplementing C metabolism or acquiring trace organic growth factors, since feeding occurs, although at a reduced rate, in nutrient-replete cultures.