Molecular Soil Biology 2025, Vol.16, No.1, 37-44 http://bioscipublisher.com/index.php/msb 40 help plants return to normal growth (Xu, 2006). 4.2 Effects of environmental stress on the active components of Leonurus japonicus Leonurus japonicus will adjust the metabolic process in the body and change the synthesis of some medicinal ingredients in adversity. Drought will promote plants to produce more secondary metabolites, such as carnosine and leonurine (Shen et al., 2002). Plants will use more resources to synthesize defense substances rather than continue to grow (Rong et al., 2022). If temperatures are too high or drought persists for too long, some plant enzymes, such as those responsible for synthesizing flavonoids and phenolic acids, become inactive. These substances inherently have antioxidant properties, and a decrease in their levels can also reduce plant resistance (Miao et al., 2019). Nitrogen deficiency can also reduce alkaloid synthesis (Xie et al., 2019). 4.3 Antioxidant changes inLeonurus japonicus under environmental stress Under stressful conditions, Leonurus japonicus activates its antioxidant system to combat reactive oxygen species (ROS) generated by the harsh environment. Under drought and high temperatures, plants produce large amounts of superoxide anions and hydrogen peroxide, which damage cell membranes. Leonurus japonicus increases the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) (Shang et al., 2014). In addition to these enzymes, it also produces non-enzymatic antioxidants such as flavonoids and phenolic acids. These substances can scavenge ROS in the body. Flavonoid production increases significantly during periods of water shortage (Cha, 2021). 5 Cultivation Techniques and Environmental Control for Leonurus japonicus 5.1 The difference between greenhouse and open-field cultivation When Leonurus japonicus is grown in a greenhouse, temperature, humidity, and light intensity can be manually controlled, which helps increase the content of medicinal ingredients such as carnosine and leonurine. The greenhouse environment is more stable, the plants are less susceptible to external influences, and pests and diseases are less common, resulting in more reliable yield and quality (Xu, 2006). In contrast, open-field cultivation is significantly affected by weather, such as temperature fluctuations, heavy rain, and drought, which can affect yield and quality. Although open-field cultivation is cost-effective and suitable for large-scale operations, its active ingredients are less stable. The choice of cultivation method should be determined based on cost and target quality (Shen et al., 2002). 5.2 The role of environmental control in cultivation (climate and light) In order to make Leonurus japonicus grow better, many growers now use automatic control equipment to adjust temperature and humidity, which can avoid the impact of extreme weather and reduce the problem of water shortage (Zhang et al., 2022). The automatic irrigation system can also save water and make cultivation more efficient. In terms of lighting, some greenhouses will be equipped with LED lights or shading equipment to control the intensity and duration of light, regulate the photosynthesis of plants, and promote the production of some important components such as flavonoids and phenolic acids. Changing the wavelength of light can also affect the metabolism of plants and improve the efficacy (Miao et al., 2019). 5.3 Effects of hydroponics onLeonurus japonicus Hydroponics is a soil-free cultivation method where plants absorb nutrients directly from the nutrient solution. This method allows for more precise control of nutrient content and reduces soil-borne disease risks, promoting rapid plant growth and increasing the content of medicinal ingredients (Tan et al., 2018). Hydroponic systems use less water, are less prone to soil-borne diseases, and are environmentally friendly. However, this method requires high initial investment and technical skills. Nevertheless, it is still a high-quality
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