Canola (Brassica napus) is one of several important oil-producing crops, and the physiological processes, enzymes, and genes involved in oil synthesis in canola seeds have been well characterized. However, relatively little is known about the dynamic metabolic changes that occur during oil accumulation in seeds, as well as the mechanistic origins of metabolic changes. To explore the metabolic changes that occur during oil accumulation, we isolated metabolites from both seed and silique wall and identified and characterized them by using gas chromatography coupled with mass spectrometry (GC-MS). The results showed that a total of 443 metabolites were identified from four developmental stages. Dozens of these metabolites were differentially expressed during seed ripening, including 20 known to be involved in seed development. To investigate the contribution of tissue-specific carbon sources to the biosynthesis of these metabolites, we examined the metabolic changes of silique walls and seeds under three treatments: leaf-detachment (Ld), phloem-peeling (Pe), and selective silique darkening (Sd). Our study demonstrated that the oil content was independent of leaf photosynthesis and phloem transport during oil accumulation, but required the metabolic influx from the silique wall. Notably, Sd treatment resulted in seed senescence, which eventually led to a severe reduction of the oil content. Sd treatment also caused a significant accumulation of fatty acids (FA), organic acids and amino acids. Furthermore, an unexpected accumulation of sugar derivatives and organic acid was observed in the Pe- and Sd-treated seeds. Consistent with this, the expression of a subset of genes involved in FA metabolism, sugar and oil storage was significantly altered in Pe and Sd treated seeds. Taken together, our studies suggest the metabolite profiles of canola seeds dynamically varied during the course of oil accumulation, which may provide a new insight into the mechanisms of the oil accumulation at the metabolite level.

The safety climate is becoming more and more important in the processes of subway operation safety management due to various accidents. The research objective of this study is to explore the effects of safety climate and personal factors on safety behavior in subway operation. First, a conceptual model is developed based on the literature review and expert experience. Then, data are collected from 352 workers in the Xuzhou subway operation company by questionnaire survey. Third, the structural equation model is employed to do model analysis based on SPSS and AMOS, and the final model is achieved through a serious of model tests and modification. At last, the quantitative effect of safety climate on worker’s safety behavior in subway operation is obtained and analyzed. The results show that the descending order of total influence effect of safety climate on safety behavior is safety attitude (0.36), safety communication (0.265), safety policy (0.238), safety education and training (0.1), management commitment (0.099), and safety participation (0.073), respectively. The total influence effects of mediator variables (safety awareness and safety ability) are 0.242 and 0.194, respectively. This study would be beneficial by offering recommendations in regard to worker’s safety behavior to raise the safety level in subway operation.

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