Physiological Responses of and to Combined Stress of Diesel Fuel and Sr Stress in Soil.

Diesel spills and nuclides pollution cause global ecosystem and human health problems. The remediation of contaminated soil using woody plants has received considerable attention. Differences in plant species and sex can lead to differences in tolerance to various stressors. We aimed to investigate the response of male and female seedlings of and to diesel and Sr stress and to compare the enrichment characteristics of Sr in trees. Male and female seedlings of and were treated with diesel fuel and 0, 10 (low), and 100 (high) mg Kg of Sr. Results showed that and had good enrichment characteristics and tolerance. had a more robust tolerance and ability to remediate contaminated soil than . The defense mechanisms of both female seedlings in response to stress were similar, while males showed different defense strategies. Male trees had higher Sr enrichment capacity, antioxidant enzymes, soil enzyme activity, and soluble matter content, indicating that males had higher tolerance capacity than females. Under diesel stress alone, the reduced photosynthetic rate of male seedlings of was mainly limited by stomatal factors, and their photosynthetic system was more tolerant to diesel. POD and APX activities, as well as alkaline phosphatase and urease activities in the soil, were significantly higher in seedlings than in , indicating that seedlings were more resistant to diesel pollution. At low concentrations of the Sr complex, diesel and Sr showed antagonistic effects in reducing the damage caused by stress. As the Sr concentration increased, damage to the plants manifested primarily through synergistic enhancement. The results of this study provide a scientific basis for the remediation of diesel fuel and nuclides contaminated soils using woody plants.