Organic material plays an essential role in the ecological restoration of different types of surfaces with engineering damage in extremely fragile environments. An outdoor mesocosm experiment was conducted to explore the effects of modified organic material on chemical, physical properties and microbial communities of reconstructed soil in ecologically restored engineering slopes of the Qinghai-Tibetan plateau. The physical and chemical properties of the soil indicate that the addition of modified organic materials significantly improves soil nutrients. In this area, organic carbon increased by 1.87 g.kg(-1) in the frame beam slopes compared with the control area, and the potassium content doubled. In addition, modified organic material effectively induced soil metabolism responses, mainly promoting the activities of soil enzymes like amylase, cellulase, urease, sucrase, and alkaline phosphatase. Moreover, addition of modified organic material noticeably changed the abundance and structure of microbial communities in soils. The enhanced concentrations of the signal molecules N-acylated-L-homoserine lactone and auto inductor peptide indicated that addition of modified organic materials significantly influenced quorumsensing in soil microbial communities. There are differences in the soil improvement effects of different types of slopes, among which the frame grid beam has the best effect. These findings demonstrate the effect and underlying mechanisms of the addition of incorporating modified organic materials, primarily sodium carboxymethyl cellulose and anionic polyacrylamide, into the soil of engineering slopes. These results have extensive application prospects for ecological restoration in strict environments.

Soil salinity is one of the most severe abiotic stress factors affecting crop growth and yield. Among the molecules used to mitigate the adverse effects of salt, melatonin (MT) and the nitric oxide donor sodium nitroprusside (SNP) played a crucial role in mediating plant responses to salt stress. However, the molecules are worthy of further consideration and investigation with regard to the secondary metabolism of plants suffering from salt stress. Herein, the potential role of MT and SNP in alleviating/buffering the negative effects of salt stress on sage (Salvia officinalis L.) seedlings was investigated. In this context, MT (0, 50 mu M, and 100 mu M) and SNP (0, 50 mu M, and 100 mu M) were applied individually. The interactive effects of each molecule with salt stress (50 and 100 mM NaCl) were assessed using a range of morpho-physiological, biochemical and analytical parameters of sage. The results of the study showed that high salinity (100 mM NaCl) critically reduced growth and photosynthetic traits and increased oxidative stress damage parameters. On the other hand, high concentrations (100 mu M) of MT or SNP treatments significantly improved growth, enhanced photosynthetic traits and mitigated oxidative stress damage parameters. For instance, individual treatments of both MT and SNP enhanced tolerance of sage against salinity stress by increasing relative water content, proline, total carbohydrates, total phenolics and flavonoid content, and the antioxidant enzymes and DPPH scavenging activities. Essential oil yield and individual essential oil compounds were also increased by MT and SNP. Overall, these molecules can be considered as potential protective agents against salinity stress in sage seedlings.