Effects of pH on growth and biochemical responses in Agarophyton vermiculophyllum under different temperature conditions

• Published in: Journal of applied phycology 2020-02, Vol.32 (1), p.499-509
• Main Authors: Samanta, Palas, Jang, Sojin, Shin, Sookkyung, Kim, Jang Kyun
• Format: Article
• Language: English
• Subjects: Acidification; Agarophyton vermiculophyllum; Alkalizing; Biomedical and Life Sciences; Carotenoids; Catalase; Chlorophyll; Chlorophyll a; Ecology; Freshwater & Marine Ecology; Glutathione; Glutathione peroxidase; Glutathione reductase; Glutathione transferase; Growth rate; High temperature; Hydrogen peroxide; Life Sciences; Lipid peroxidation; Lipids; Oxidative stress; Peroxidase; Peroxidation; pH effects; Phycocyanin; Physiology; Plant Physiology; Plant Sciences; Reactive oxygen species; Reductases; Scavenging; Seawater; Superoxide dismutase; Temperature effects
• ISSN: 0921-8971; 1573-5176
• DOI: 10.1007/s10811-019-01933-3

The effects of pH (6.2, 7.2, 8.2, 9.2, and 10.2) under rising temperature (30 °C vs 20 °C) on Agarophyton vermiculophyllum growth and bio-physiology were investigated. Results showed that A. vermiculophyllum exhibited lower growth rates under elevated temperature in all pH values. Chlorophyll a , carotenoid, and phycocyanin levels were significantly enhanced by temperature elevation ( p < 0.05). Enhanced H 2 O 2 production either at lower or higher pH values correlated with lipid peroxidation (LPO) levels under elevated temperature, which suggested oxidative stress development. Oxidative damage was more severe at elevated pH values, which is confirmed by higher reactive oxygen species (ROS) levels. Compared with ambient pH 8.2 value, lower pH values under elevated temperature lead to increase activities of superoxide dismutase (SOD), catalase (CAT), and glutathione S -transferase (GST), indicating that these enzymes played an important role to combat stress. However, decreased glutathione reductase (GR) and glutathione peroxidase (GPx) activities indicate least contribution for ROS scavenging at lower pH values. On contrary, SOD and CAT declined at elevated pH values compared with ambient pH, suggesting least contribution for ROS removal. Moreover, enhanced GR and GPx activities at elevated pH and temperature are not enough to scavenge ROS production. These data are consistent with higher H 2 O 2 and LPO levels, and lower GST activities. Collectively, our results indicated that either pH fluctuations or elevated temperature displayed a disadvantageous influence on growth and bio-physiology of A. vermiculophyllum . Therefore, rising temperature alleviates adverse effects of seawater acidification, but it aggravates the negative effects of seawater alkalization on growth and bio-physiology of A. vermiculophyllum .