COMPARATIVE PHYSIOLOGY OF SYNECHOCOCCUS AND PROCHLOROCOCCUS - INFLUENCE OF LIGHT AND TEMPERATURE ON GROWTH, PIGMENTS, FLUORESCENCE AND ABSORPTIVE PROPERTIES
COMPARATIVE PHYSIOLOGY OF SYNECHOCOCCUS AND PROCHLOROCOCCUS - INFLUENCE OF LIGHT AND TEMPERATURE ON GROWTH, PIGMENTS, FLUORESCENCE AND ABSORPTIVE PROPERTIES
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DOI：
10.3354/meps116259
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发表时间：
1995-01-01
影响因子：
2.5
通讯作者：
CHISHOLM, SW
中科院分区：
文献类型：
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作者：
MOORE, LR;GOERICKE, R;CHISHOLM, SW
海洋原绿球藻在世界海洋中分布广泛，在地理上总是与海洋蓝细菌聚球藻共存。在大西洋中，这两个微微微扰子表现出不同的空间和季节分布。为了更好地了解这些物种的生态，我们测量了生长和光适应反应，包括荧光激发[F*（ph）（lambda）]和在体内吸收[a*（ph）（lambda）]光谱在一个范围内的生长辐照度为P. marinus（克隆SS 120）和Synechococcus WH 8103，都从马尾藻海分离。为了探索海洋原甲藻的生理多样性，我们测量了从地中海分离的另一个海洋原甲藻克隆MED 4的生理反应。还检查了所有3个克隆的生长速率随温度的变化。海聚球藻SS 120和聚球藻WH 8103的最适生长温度不同，但这并不能解释北大西洋不同的纬度分布。海洋聚球藻SS 120比聚球藻WH 8103更适合在弱光下生长，这与海洋聚球藻和聚球藻在野外的相对深度分布相一致。海洋聚球藻MED 4的光依赖性生长反应与聚球藻WH 8103的光依赖性生长反应比与海洋聚球藻SS 120的光依赖性生长反应更相似。海洋假单胞菌独特的色素含量（含有二乙烯基叶绿素a和B）导致在蓝色波长处的最大吸收。海洋聚球藻SS 120具有较高的总叶绿素B/叶绿素a比值，在低光强下比聚球藻WH 8103（和海洋聚球藻MED 4）吸收更多的光，生长速度更快，在真光区较聚球藻竞争力更强。在高生长辐照度下，P. marinus SS 120含有可测量量的正常（单乙烯基）chl B b，而在任何生长辐照度下，在P. marinus MED 4中均未发现该色素。色素比例的光适应性变化，而不是包装效应，解释了所有3个皮细胞的a*（ph）（lambda）和F*（ph）（lambda）随光强度的大部分变化。在高光强度下，玉米黄质对蓝色中的a*（ph）（lambda）有很大贡献，但基于F*（ph）（lambda）测量，似乎很少或没有将激发能转移到反应中心。对于P. marinus，由于二乙烯基叶绿素a和B相对于正常叶绿素a和B的高吸收，由于玉米黄质的吸收，以及小的细胞尺寸导致相对于a*（ph）（红色）异常高的a*（ph）（蓝色）。
Prochlorococcus marinus is abundant and widespread throughout the world's oceans and always co-occurs geographically with the marine cyanobacterium Synechococcus. In the Atlantic Ocean, these 2 picoplankters exhibit different spatial and seasonal distributions. In order to better understand the ecology of these species, we measured growth and photoacclimation responses including fluorescence excitation [F*(ph)(lambda)] and in vivo absorption [a*(ph)(lambda)] spectra over a range of growth irradiances for P. marinus (clone SS120) and Synechococcus WH8103, both isolated from the Sargasso Sea. To explore the physiological diversity of P. marinus, we measured the physiological responses of another P. marinus clone, MED4, isolated from the Mediterranean Sea. Growth rate as a function of temperature was also examined for all 3 clones. P. marinus SS120 and Synechococcus WH8103 have different temperature optima for growth, but these do not explain the different latitudinal distributions in the North Atlantic. P. marinus SS120 is adapted for growth at low light intensities relative to Synechococcus WH8103, which is consistent with the relative depth distribution of P. marinus and Synechococcus in the field. The light-dependent growth response of P. marinus MED4 is more similar to Synechococcus WH8103 than to P. marinus SS120. The unique pigment content of P. marinus (which contain divinyl chlorophylls a and b) results in maximal absorbance in the blue wavelengths. The high total chl b/chl a ratio of P. marinus SS120 enables it to absorb more light, grow faster than Synechococcus WH8103 (and P. marinus MED4) at low light intensities, and presumably to outcompete Synechococcus in the deep euphotic zone. At high growth irradiances, P. marinus SS120 contains measureable amounts of normal (monovinyl) chl b, whereas this pigment was not found in P. marinus MED4 at any growth irradiance. Photoacclimative changes in pigment ratios, and not package effect, account for most of the changes in a*(ph)(lambda) and F*(ph)(lambda) With Light intensity for all 3 picoplankters. At high light intensities, zeaxanthin contributes substantially to a*(ph)(lambda) in the blue, but appears to transfer little or no excitation energy to the reaction centers, based on F*(ph)(lambda) measurements. For P. marinus, high absorption in the blue due to divinyl chl a and b relative to normal chi a and b, absorption due to zeaxanthin, and small cell size result in unusually high a*(ph) (blue) relative to a*(ph) (red).