Buoyancy regulation of Microcystis flos-aquae during phosphorus-limited and nitrogen-limited growth
Buoyancy regulation of Microcystis flos-aquae during phosphorus-limited and nitrogen-limited growth
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DOI：
10.1093/plankt/fbm054
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发表时间：
2007-09-01
影响因子：
2.1
通讯作者：
Zeng, Qingru
中科院分区：
文献类型：
--
作者：
Chu, Zhaosheng;Jin, Xiangcan;Zeng, Qingru
气泡蓝藻的优势通常归因于它们的浮力以及它们对环境条件做出反应的浮力调节能力。研究了水华微囊藻在氮限制、磷限制和营养充足生长过程中绝对气泡体积、碳水化合物含量、蛋白质含量和菌落浮力的变化。当营养充足时，水华分枝杆菌细胞始终有多余的气泡，这提供了足够的浮力，每天碳水化合物的变化对细胞的影响。漂浮量可以忽略不计。然而，在氮素限制生长过程中，随着氮素耗竭，细胞内的气泡体积显著减少。气泡体积最大降幅达84-88%。同时，细胞内碳水化合物含量也有积累趋势。气泡浮力的减小和碳水化合物的每日增加可以解释细胞浮力的日变化。在磷限制生长期间，每个细胞的气泡体积略有减少(最大为22-32%)，但它们仍然提供足够的浮力，使大多数细胞保持漂浮，即使每天有显著的碳水化合物变化。由于氮限制引起的浮力损失比磷限制引起的浮力损失更大，在氮限制水体中表层水华可能消失或频繁出现，而在磷限制水体中可能持续更长时间。气泡、碳水化合物和蛋白质浮力变化的定量分析表明，长期的浮力调节主要取决于气泡体积的变化，而短期的浮力调节主要取决于碳水化合物的积累和消耗。长期和短期浮力调节都受到细胞营养状态的影响。此外，每个细胞和蛋白质的气泡体积。限氮和限磷生长的气泡含量变化规律相同，说明气泡的减少与总蛋白合成的控制有关。
The dominance of gas-vacuolate cyanobacteria is often attributed to their buoyancy and to their ability to regulate buoyancy in response to environmental conditions. Changes in absolute gas vesicles volume, carbohydrate content, protein content and colony buoyancy of Microcystis flos-aquae were investigated during nitrogen-limited, phosphorus-limited and nutrient-replete growth. When, nutrient-replete, M. flos-aquae cells consistently had excess gas vesicles, which provided sufficient buoyancy that the influence of daily carbohydrate changes on cells upon. floatation was negligible. However, during nitrogen-limited growth gas vesicle volume per cell decreased significantly with nitrogen exhaustion. The maximum decrease of gas vesicle volume was up to 84-88%. At the same bane, cellular carbohydrate content, had an accumulation trend. The decrease of gas vesicle buoyancy together with the daily increase in carbohydrate are suggested to explain the daily changes in the cell floatation. During phosphorus-limited growth gas vesicle volume per cell decreased slightly (maximum to 22-32%), and they still provided sufficient buoyancy that most cells kept floating even though there were significant daily carbohydrate changes. Since nitrogen limitation caused more significant buoyancy loss than phosphorus limitation did, surface water blooms may disappear or appear frequently in nitrogen limited water bodies while they may persist a longer time in phosphorus limited water bodies The quantitative analysis in buoyancy change by gas vesicles, carbohydrate and protein suggested that long-term buoyancy regulation was mainly determined by changes of gas vesicle volume whereas short-term buoyancy regulation was mainly determined by carbohydrate accumulation and consumption. Both long-term and short-term, buoyancy regulation were influenced by cell nutrient status. Furthermore, gas vesicle volume per cell and protein. content changed in the same way in both nitrogen-limited and phosphorus-limited growth which implied that the decrease of gas vesicles were associated with controls of total protein synthesis.