EFFECT OF IRRADIANCES UP TO 2000 MU-E M-2 S-1 ON MARINE SYNECHOCOCCUS WH7803 .2. PHOTOSYNTHETIC RESPONSES AND MECHANISMS
EFFECT OF IRRADIANCES UP TO 2000 MU-E M-2 S-1 ON MARINE SYNECHOCOCCUS WH7803 .2. PHOTOSYNTHETIC RESPONSES AND MECHANISMS
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DOI：
10.1016/0198-0149(87)90002-1
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发表时间：
1987-04-01
期刊：
影响因子：
--
通讯作者：
GLIBERT, PM
中科院分区：
文献类型：
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作者：
KANA, TM;GLIBERT, PM
研究了在30 ~ 2000 .mu辐照范围内生长的聚球菌WH7803的光合行为。E m-2 s-1在营养充足，连续光照，预适应的批量培养中。对于所研究的8种生长辐照度中的每一种，我们都发现了独特的光合作用与辐照度（P vs I）关系。细胞和碳特异性光合作用光收集效率。(Cell和。alpha。(C)从最低到最高的生长辐照度下降了10倍。叶绿素和藻蓝蛋白特异性效率也有所下降，但程度较轻。随着辐照度的增加，藻红蛋白特异性效率增加约2倍。光合能力（Pmax）仅在饱和生长速率的生长辐照度下近似于原位光合速率（Pi）；在限光辐照下，Pmax增加到Pi的2.9倍。光抑制作用仅在限光细胞中观察到。光适应机制导致了观察到的生长速率与辐照度（.mu）的关系。vs I)反应涉及α的调节。（细胞）通过饱和照射时藻胆酶体大小的变化和限制照射时藻胆酶体数量的变化。我们的结果与先前报道的.alpha的野外观测结果一致。(背影),.alpha。（细胞）和Pmax随着深度的增加而增加，并且对近地表收集的组合没有光抑制作用，这表明近地表水域的高辐照度可以支持聚珠球菌的最大生长速度。这些结果提出了关于从现场研究中解释P vs I测量参数的重要问题。我们的结果不符合先前报道的假设，即在这些细胞中有很大比例的藻红蛋白作为非光合氮储存化合物。
We investigated the photosynthetic behavior of Synechococcus WH7803 when grown over the irradiance range of 30-2000 .mu.E m-2 s-1 in nutrient-replete, continuous light, preadapted batch cultures. For each of 8 growth irradiances investigated, we found a unique photosynthesis vs irradiance (P vs I) realtionship. Cell- and carbon-specific photosynthetic light harvesting efficiencies (.alpha.(Cell and .alpha.(C)) decreased 10-fold from the lowest to highest growth irradiances. Chlorophyll and phycocyanin-specific efficiencies also decreased but to a lesser extent. Phycoerythrin-specific efficiences increased ca. 2-fold with increasing irradiances. Photosynthetic capacity (Pmax) approximated the in situ rate of photosynthesis (Pi) only at growth irradiances which saturated growth rate; at light limiting irradiances, Pmax increased to 2.9 times Pi. Photoinhibition of photosynthesis was only observed in light-limited cells. The mechanism of photoadaptation which resulted in the observed growth rate vs irradiance (.mu. vs I) response involved regulation of .alpha.(cell) by changes in phycobilisome size over saturating irradiances and phycobilisome numbers over limiting irradiances. Our results are consistent with previously reported field observations of .alpha.(Chl), .alpha.(cell) and Pmax increasing with depth, and of no photoinhibition of of near-surface collected assemblages, suggesting that high irradiances in near-surface waters can support maximal growth rates of Synechococcus. These results raise important questions regarding the interpretation of parameters of P vs I measurements from field studies. Our results do not conform to the previously reported hypothesis that a significantly percentage of phycoerythrin serves as a non-photosynthetic nitrogen storage compound in these cells.