Nitric oxide indicates the response of Chlorella sp. to ocean warming and its potential mechanisms
摘要
Nitric oxide (NO) is a kind of plant signal molecule with high diffusion rate and high reactivity, which plays an important role in regulating plant physiology and growth. To examine its function as a growth indicator and the adaptive mechanisms of Chlorella sp. to ocean warming, we increased the cultivation temperature of algae during their growth period from 20 °C to 25 °C. Our research results indicate that the changes in NO concentration outside the algal body were consistent with the growth of algae during the lag and logarithmic growth phases, as well as the decline during the stationary phase, which imply that the change in NO concentration could indicate the growth status of Chlorella sp. At different temperatures, the changes in NO concentration, Fv/Fm, and reactive oxygen species levels in algae were consistent, suggesting that NO may indicate changes in the photosynthetic and antioxidant systems of algae. Compared with 20 °C, Chlorella sp. grown at 25 °C experienced higher levels of NO in vitro (17.0%) and in vivo (32.1%), with higher biomass (30.1%) and Fv/Fm (6.1%). When the temperature increased from 20 °C to 25 °C, there were significant changes in the pH value, dissolved inorganic carbon, and pCO2 in the algal culture medium. Therefore, Chlorella sp. can maintain growth and development in high NO environments by regulating the photosynthesis and antioxidant systems of algae to cope with ocean warming.