低温等离子体可引起丰富的生物效应，包括生物刺激效应。雨生红球藻是自然界高产天然虾青素（一种强抗氧化剂）的微生物，人们对进一步提高虾青素产量有重要需求。在研究中我们发现，低温等离子体在非诱变条件下可以促进雨生红球藻生长和提高虾青素产量，但具体原因并不清楚。因为低温等离子体可产生丰富的活性氧（ROS），而ROS可以激发雨生红球藻特殊保护机制，所以我们推测这主要是等离子体产生ROS引起氧化胁迫下的刺激作用。为此，本项目提出低温等离子体刺激雨生红球藻促产虾青素的方案，并由此探索相关作用机理。研究中，一方面优化等离子体处理条件，另一方面对相关生物过程进行分析，通过分析活性氧、代谢产物、抗氧化酶活等，探讨其中的抗氧化酶保护机制和虾青素保护机制以及两者之间关系和转化过程。该项研究不仅可加深等离子体对生物作用机理的认识，而且可拓宽低温等离子体技术应用，有望为雨生红球藻高产虾青素提供新的技术和方法。

Irradiation of non-thermal low-temperature plasma on microorganisms can induce a variety of biological effects, including the hormesis effect under certain conditions. Haematococcus pluvialis (H. pluvialis) is a freshwater species of Chlorophyta from the family Haematococcaceae, well known for its high content of the strong antioxidant astaxanthin (a strong antioxidant) of microorganism, and it is still a challenge to promote growth and improve the yield of astaxanthin. In our preliminary experiments, we found that plasma irradiation can promote the growth of H. pluvialis and promote the production of astaxanthin, but the mechanism is still elusive. It is well known that plasma can produce reactive oxygen species (ROS), and ROS can initiate the special protective mechanism of H. pluvialis, we therefore have the hypothesis that this effect is mainly caused by ROS-oxidative stress stimulation under plasma irradiation. Therefore, in this project we put forward to employ non-thermal plasma as a novel method to stimulate H. pluvialis growth and promote astaxanthin production, and also to explore the underlying mechanism. In the research, we will on one hand explore the optimal conditions for plasma treatment result, while on the other hand scrutinize the involved biological processes. We will analyze the effect of different types of ROS, metabolites, antioxidant enzyme activities, so as to clarify the two different defense mechanisms, namely, the antioxidant defense mechanism and the astaxanthin defense mechanism, as well as the relationship between them. As such, this study will not only contribute to the better understanding of the effect of non-thermal low-temperature plasma on microorganisms, but also open a new door for the application of low-temperature plasma, and may provide a new solution for the promotion of production of astaxanthin in H. pluvialis in practical application.