Shi Xiaohan, Zou Dinghui, Hu Shanshan, Mai Guangming, Ma Zengling, Li Gang
School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
Key Laboratory of Tropical Marine Bioresources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China.
Plants (Basel). 2021 Nov 12;10(11):2441. doi: 10.3390/plants10112441.
Biochemical compositions and photosynthetic characteristics of three naturally cohabitated macroalgae, , and , were comparably explored in the field conditions in Daya Bay, northern South China Sea, as well as their responses to temperature rise. Chlorophyll (Chl ) and carotenoids contents of were 1.00 ± 0.15 and 0.57 ± 0.08 mg g in fresh weight (FW), being about one- and two-fold higher than that of and ; and the carbohydrate content was 20.3 ± 0.07 mg g FW, being about three- and one-fold higher, respectively. Throughout the day, the maximal photochemical quantum yield (F/F) of Photosystem II (PS II) of these three macroalgae species decreased from morning to noon, then increased to dusk and kept steady at nighttime. Consistently, the rapid light curve-derived light utilization efficiency (α) and maximum relative electron transfer rate (rETRmax) were lower at noon than that at morning- or night-time. The F/F of (varying from 0.78 to 0.32) was 38% higher than that of throughout the day, and that of was intermediate. The superoxide dismutase (SOD) and catalase (CAT) activities in were lower than that in and . Moreover, the rises in temperature species-specifically mediated the damage () caused by stressful high light and the corresponding repair () to photosynthetic apparatus, making the / ratio increase with the rising temperature in , unchanged in but decreased in . Our results indicate that may compete with or and dominate the macroalgae community under aggravatedly warming future in the Daya Bay.
在中国南海北部大亚湾的野外条件下，对三种自然共生的大型海藻（龙须菜、半叶马尾藻和异枝麒麟菜）的生化组成和光合特性进行了比较研究，以及它们对温度升高的响应。龙须菜的叶绿素a（Chl a）和类胡萝卜素含量在鲜重（FW）中分别为1.00±0.15和0.57±0.08 mg g，分别比半叶马尾藻和异枝麒麟菜高约1倍和2倍；碳水化合物含量为20.3±0.07 mg g FW，分别比后两者高约3倍和1倍。在一整天中，这三种大型海藻的光系统II（PS II）的最大光化学量子产率（Fv/Fm）从早晨到中午下降，然后在黄昏时增加，并在夜间保持稳定。一致地，快速光曲线得出的光利用效率（α）和最大相对电子传递速率（rETRmax）在中午低于早晨或夜间。龙须菜的Fv/Fm（从0.78变化到0.32）全天比半叶马尾藻高38%，而异枝麒麟菜的Fv/Fm处于中间水平。龙须菜中的超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性低于半叶马尾藻和异枝麒麟菜。此外，温度升高以物种特异性方式介导了由胁迫性强光引起的损伤（Y）和光合机构的相应修复（R），使得Y/R比值在龙须菜中随温度升高而增加，在半叶马尾藻中不变，但在异枝麒麟菜中降低。我们的结果表明，在未来大亚湾温度加剧升高的情况下，龙须菜可能会与半叶马尾藻或异枝麒麟菜竞争并主导大型海藻群落。
