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Previous researchers have focused on the role of 24-epibrassnolide (EBR) in alleviating stresses in plants, whereas the effect of EBR on rice grain yield formation from the perspective of the whole growth stage remains less concerned. To further confirm the optimal application concentration and application periods of EBR in rice (Oryza sativa L.) under salt stress, a seed germination experiment, a seedling experiment, and a pot experiment were designed and conducted. Results showed that EBR treatment significantly enhanced germination indicators and seedling morphological traits, and the effects varied among different EBR concentrations, which were 0.5 > 1.0 > 0.1 > 0.05 mg L−1. Under 0.5% salt treatments, 0.5 mg L−1 EBR spraying significantly enhanced the seedling height, root length, above-/under-ground fresh weight, and above-/under-ground dry weight by 9.2%, 15.9%, 48.0%, 19.5%, 29.3%, and 12.5%, respectively. The spraying of EBR at different periods enhanced rice yield by 6.7% to 94.4% under salt stress. The relatively higher panicle number (increased by 42.9%) and spikelet number per panicle (increased by 96.1%) were the main reason resulting in higher grain yield under the S+T5 (EBR sprayed at both transplanting and heading stage) treatment. Compared to those under S treatment, catalase (CAT) activity was significantly enhanced by 25.0%, while malondialdehyde (MDA) content was dramatically decreased by 37.3% under the S+T5 treatment. The S+T5 treatment significantly enhanced the K+ content in rice root and leaf and decreased the Na+ content in rice root (by 30.4%), thereby leading to higher K+/Na+ under salt stress. The current study concluded that 0.5 mg L−1 was the optimal concentration of EBR in alleviating the adverse effect of salinity. Spraying (transplanting + heading) of EBR twice displayed the best alleviating effect under salt stress, which was realized through enhanced antioxidant enzyme, higher K+ maintenance in leaves, and lowered absorption of Na+ in rice root. [ABSTRACT FROM AUTHOR]

With the rapid development of urban rail transit, the environmental vibration and secondary noise induced by metro train operation have become increasingly serious, posing stricter requirements on the vibration and secondary noise of sensitive building office (SBO) and sensitive building school (SBS). To predict and control the vibrations and secondary noise in sensitive buildings along the metro line induced by metro train operations. A prediction method for the vibration and secondary noise of sensitive buildings along the metro line during metro train operation has been proposed. The sub-model of train-track system coupled dynamics and the sub-model of track-tunnel-soil-building system dynamics are included. The influence of metro train operation on the vibration and secondary noise of SBO and SBS is studied. The influence of the distance between the metro line and the building on the vibration and secondary noise of the sensitive building is discussed, and an effective control scheme of vibration and secondary noise is proposed. Results show that the vibration frequencies of the SBS and the SBO caused by the metro train operation are concentrated at about 8Hz and 63Hz. The vibration below the second floor of SBO caused by the metro train operation exceeds the limit, and the secondary noise below the third floor of SBS exceeds the limit. The secondary noise inside the building of each floor of SBO exceeded the limit. Using secondary noise to evaluate the environmental impact of metro train operations is more stringent than relying solely on vibration assessments. secondary noise is recommended in engineering to assess the impact of metro train operation on sensitive buildings along line. Combined with vibration, secondary noise and construction requirements, SBS and SBO are recommended to be no less than 72m and 74m away from the metro line, respectively. [ABSTRACT FROM AUTHOR]