Lead (Pb) is a major anthropogenic contaminant that can be devastating on both animals and plants. It is essential to develop methods to decrease the Pb contaminant in soil by phytoremediation using plants that are tolerance to Pb. In this study, we investigated the tolerance of bermudagrass (Cynodon dactylon (L.) Pers.) and the role of exogenous application of melatonin for improving its tolerance to Pb. Bermudagrass growing in soil treated with Pb at 1,000 or 2,000 mg kg⁻¹ were assessed with or without melatonin pretreatment at various concentrations. Under Pb stresses, bermudagrass plants showed stunted growth and increased cellular oxidative stress. Pre-treating bermudagrass plants with melatonin at 20 or 100 μM significantly increased the activities of antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase) and the contents of non-enzymatic antioxidants (ascorbic acid and glutathione), and decreased reactive oxygen species (hydrogen peroxide, superoxide), and ultimately reduced membrane lipid peroxidation and permeability. These changes contributed to improvements in the water status, photosynthetic pigment synthesis, and biomass production of bermudagrass under Pb stresses. Our study provides the first evidence that melatonin may be a promising tool for enhancing Pb tolerance and phytoremediation potential of bermudagrass.

Human health is closely related to the environment; a relaxing and pleasant landscape environment can make people feel less stressed and more energetic. To investigate the restorative potential of landscape types and landscape elements in the post-epidemic era from the perspective of visual perception, this study selected Sichuan Agricultural University’s Laoban hill, Jiuqu bridge, and the ginkgo garden to carry out physiological and psychological measurement experiments with college students. Research results on the psycho-biological and perceptual recovery vary with the types of landscape spaces. The results of the physiological data showed that all three space types had no significant effect on the recovery of blood pressure and heart rate; Laoban hill and Jiuqu bridge had some impact on concentration, while the ginkgo garden had no significant effect; and all three space types had some effect on the relaxation of the subjects’ mental state. The results of the psychological data showed that the subjects’ emotions were significantly improved in the three different landscape space types. The space with the strongest restorative effect on negative emotions was the ginkgo garden, followed by Jiuqu bridge and Laoban hill. The spaces with the strongest restorative potential for positive emotions were Jiuqu bridge and the ginkgo garden, followed by Laoban hill. The results of the perceptual restoration data showed that the Laoban hill space had the most effective restorative potential on the human body, followed by Jiuqu bridge, with the ginkgo garden having the least effective restorative potential. The results of the study on the difference between the aesthetic preference of different landscape elements and the perception restorative effect of a space showed that “the harmony between artificial structures such as garden pieces and the environment”, “plant species”, “waterscape state”, and “boundary clarity” were identified as significant landscape elements with perception-restorative effects. These findings summarize campus landscape types and elements with optimal restorative potential. In the future, in campus landscape design—an active approach with a scientific combination and configuration of campus landscape types and elements—can provide a feasible solution to enhance the potential of campus landscape restorative effects.

Indoor plants can positively impact physical and mental health in daily life. However, the benefits of viewing indoor plants may be enhanced if the plants emit a fragrant aroma. In this crossover-design study, we measured the physiological and psychological effects of fragrant and non-fragrant Primula plants on 50 female college students, and explored whether aroma stimulation had additive benefits for this group. Non-fragrant Primula malacoides Franch was used as a control stimulus, and Primula forbesii Franch, which has a floral fragrance, was used as an experimental stimulus. We measured blood pressure, pulse rate, and electroencephalogram (EEG) to evaluate physiological responses, and used a mood state profile and the semantic differential (SD) method to evaluate psychological responses. We found that mean blood pressure and pulse rate decreased significantly after the experiment in both conditions. EEGs showed that the mean values of high alpha waves, high beta waves, and relaxation scores were significantly higher in the experimental vs. control condition. The average scores on each subscale of the psychological questionnaire improved after the experiment in both conditions, and the vitality (V) subscale and total emotional state scores were significantly better in the experimental vs. control condition. The results of the SD method showed that the sense of relaxation and comfort were significantly higher in the experimental vs. control condition. Compared with the non-fragrant Primula, the fragrant Primula induced relatively better physiological and psychological effects.