采用不同脉冲调制荧光仪和氧气释放法评估 CO2、硝酸盐和温度升高对石莼（绿藻门）光合作用活性的短期影响。

Short-term effects of increased CO2, nitrate and temperature on photosynthetic activity in Ulva rigida (Chlorophyta) estimated by different pulse amplitude modulated fluorometers and oxygen evolution.

机构信息

Malaga University. Institute of Blue Biotechnology and Development (IBYDA), Ecology department, Faculty of Sciences, Campus universitario de Teatinos s/n, Malaga, Spain.

Botany department, Federal University of Santa Catarina. Campus Trindade s/n, Florianópolis, SC, Brazil.

出版信息

J Exp Bot. 2021 Feb 2;72(2):491-509. doi: 10.1093/jxb/eraa473.

DOI:10.1093/jxb/eraa473

PMID:33064811

Abstract

Short-term effects of pCO2 (700-380 ppm; High carbon (HC) and Low carbon (LC), respectively) and nitrate content (50-5 µM; High nitrogen (HN) and Low nitrogen (LN), respectively on photosynthesis were investigated in Ulva rigida (Chlorophyta) under solar radiation (in-situ) and in the laboratory under artificial light (ex-situ). After six days of incubation at ambient temperature (AT), algae were subjected to a 4 °C temperature increase (AT+4 °C) for 3 d. Both in-situ and ex-situ maximal electron transport rate (ETRmax) and in situ gross photosynthesis (GP), measured by O2 evolution, presented highest values under HCHN, and lowest under HCLN, across all measuring systems. Maximal quantum yield (Fv/Fm), and ETRmax of photosystem (PS) II [ETR(II)max] and PSI [ETR(I)max], decreased under HCLN at AT+4 °C. Ex situ ETR was higher than in situ ETR. At noon, Fv/Fm decreased (indicating photoinhibition), whereas ETR(II)max and maximal non-photochemical quenching (NPQmax) increased. ETR(II)max decreased under AT+ 4 °C in contrast to Fv/Fm, photosynthetic efficiency (α ETR) and saturated irradiance (EK). Thus, U. rigida exhibited a decrease in photosynthesis under acidification, changing LN, and AT+4 °C. These results emphasize the importance of studying the interaction between environmental parameters using in-situ versus ex-situ conditions, when aiming to evaluate the impact of global change on marine macroalgae.

摘要

短期二氧化碳（pCO2）（700-380ppm；分别为高碳（HC）和低碳（LC））和硝酸盐含量（50-5µM；分别为高氮（HN）和低氮（LN））对光合作用的影响，在太阳辐射下（原位）和在实验室人工光下（异位）对石莼（绿藻）进行了研究。在环境温度（AT）下孵育六天后，藻类在 3 天内经历了 4°C 的温度升高（AT+4°C）。在所有测量系统中，原位和异位最大电子传递速率（ETRmax）和原位总光合作用（GP），通过 O2 释放测量，在 HCHN 下呈现最高值，在 HCLN 下呈现最低值。最大量子产率（Fv/Fm）和 PSII [ETR（II）max]和 PSI [ETR（I）max]的 ETRmax 降低。在 AT+4°C 下，HCLN 下的 ETR 降低。在中午，Fv/Fm 降低（表明光抑制），而 ETR（II）max 和最大非光化学猝灭（NPQmax）增加。与 Fv/Fm 相比，在 AT+4°C 下 ETR（II）max 降低，光合效率（α ETR）和饱和辐照度（EK）降低。因此，U. rigida 在酸化、改变 LN 和 AT+4°C 下表现出光合作用的下降。这些结果强调了在原位与异位条件下研究环境参数相互作用的重要性，当旨在评估全球变化对海洋大型藻类的影响时。