In the context of contemporary climate change, drought is widely recognized as a major stressor affecting plant growth. While numerous studies have demonstrated that Serendipita indica enhances stress resistance in host plants and is widely used in agriculture, research on its symbiotic interactions with woody plants for improving drought tolerance remains limited. This study investigated the effects of S. indica inoculation on the growth of Phoebe sheareri seedlings under varying drought conditions—well-watered (WW), moderate drought (MD), and severe drought (SD)—and explored the physiological mechanisms underlying improved drought resistance. The results showed that under WW conditions, S. indica inoculation promoted seedling growth and development. Under MD and SD conditions, although drought stress inhibited growth, inoculation significantly increased plant biomass, root parameters, chlorophyll content, and photosynthetic efficiency. Additionally, it alleviated drought-induced damage by reducing REC, MDA, H₂O₂, and O₂⁻ levels, while enhancing SOD, POD, and CAT activities, and increasing root ABA, GA, IAA, and CTK content. Under MD stress, adaptive changes in root architecture and hormone levels were observed, including increases in total root length, surface area, volume, average diameter, and elevated IAA and CTK levels—all of which were further enhanced by S. indica inoculation. In conclusion, symbiosis with S. indica improved drought tolerance in P. sheareri seedlings likely through enhanced photosynthesis, antioxidant enzyme activity, and hormone regulation.

This study investigated the effects of Trichoderma harzianum inoculation on the growth, physiological responses, and soil nutrient uptake of three turfgrass species cultivated on eco-concrete—Axonopus compressus (Sw.) Beauv., Cynodon dactylon (L.) Pers., and Zoysia sinica Hance. A 2 × 2 factorial design was used to evaluate plant growth, physiological responses, and soil metrics under cement stress, incorporating T. harzianum inoculation (inoculated vs. control) and substrate composition (eco-concrete vs. pastoral soil). Our results indicate that inoculation with Trichoderma harzianum significantly enhanced the growth potential of the three turfgrass species compared to uninoculated controls. Furthermore, under cement stress conditions in vegetated concrete, inoculation with T. harzianum significantly alleviated the inhibition of growth and development. More specifically, in the vegetated concrete habitat, inoculated plants exhibited significantly increased root length and surface area. This enhancement promoted the uptake of available nitrogen (AN), available phosphorus (AP), and available potassium (AK) from the soil. Concurrently, inoculated plants showed higher leaf epidermal cell density, stomatal width, soluble sugar content, and antioxidant enzyme activity (SOD, POD, CAT, and APX). Additionally, significant reductions were observed in root activity, relative conductivity, and malondialdehyde (MDA) and proline contents. In conclusion, T. harzianum inoculation promotes the growth of the three turfgrass species under cement stress, likely by enhancing root development, increasing osmoregulatory substance accumulation, and elevating antioxidant enzyme activities.

Oil and gas drilling waste drilling fluid is a complex alkaline mixture that poses risks to plants and soil ecosystems during transportation and disposal due to potential leakage. This study investigates the effects of waste drilling fluid on the growth of Trifolium pratense (L.) and Astragalus sinicus (L.) and on the soil ecosystem, aiming to provide a theoretical reference for ecological restoration of oil and gas field sites. Four gradients of waste drilling fluid stress were established by mixing 0, 50, 100, and 150 mL of waste drilling fluid into the substrate, with 0 mL serving as the control. Seed germination, morphological development, physiological, and biochemical indices of the two leguminous plants, as well as soil nutrients and enzyme activities, were analyzed, followed by a comprehensive evaluation. Waste drilling fluid stress inhibited the growth of both leguminous plants. Their physiological and biochemical parameters, such as antioxidant enzyme activities and osmotic regulatory substances, exhibited a gradually increasing trend with increasing waste drilling fluid concentration. Concurrently, waste drilling fluid stress reduced soil nutrient availability and decreased soil enzyme activities. Notably, soil nutrient content increased after planting compared to the original soil without plants. Planting these two leguminous plants can effectively alleviate the negative impacts of waste drilling fluid stress, thereby indirectly contributing to soil remediation.