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Zanthoxylum bungeanum Maxim., an important spice plant, is rich in volatile components and has formed several cultivars in China. Genetic variation among different cultivars has significant effects on volatile components. In this study, a total of 52 volatile compounds were detected from 11 cultivars of Z. bungeanum, among which palmitic acid, (+)‐limonene, phytol, β‐caryophyllene, and terpinyl acetate were screened as characteristic compounds, with palmitic acid and phytol contributing the most to the volatile composition. Combined with the results of chemometric and content analyses, three Z. bungeanum chemotypes were identified: (+)‐limonene, β‐caryophyllene + terpinyl acetate, and palmitic acid + phytol. In addition, the dynamics of the accumulation of its main components were explored, and the optimal harvest period for Z. bungeanum leaves (late July or early August) was clarified. Moreover, histochemical analysis results showed that terpenoids were mainly accumulated in the oil cells of Z. bungeanum leaves, and there were some differences in the number of oil cells in different chemotypes of Z. bungeanum, which might affect the yield and quality of volatile components. The results showed that the differences of chemical composition among diverse chemotypes of Z. bungeanum might be an important factor leading to the quality differences of the same planting resources. Accordingly, the study on the classification of Z. bungeanum chemotypes and the accumulation patterns of major chemical components is of great theoretical significance and practical value as a favorable guarantee for the development and utilization of Z. bungeanum resources and quality control. [ABSTRACT FROM AUTHOR]

To reduce carbon emissions, the Chinese government is considering introducing a differentiated industrial carbon tax on enterprises outside the carbon trading market in the future. An efficient carbon tax must consider not only how carbon taxes impact the current economy but also how the size of the tax should be adjusted across time due to external changes. To calculate the optimal industrial carbon tax for China which is subject to certain constraints, this paper investigates the economic and environmental effects of four possible industrial carbon tax rate models under carbon intensity constraints from 2021 to 2030 by a dynamic input–output optimization model. The results show that the dynamic tax rate model leads to larger fluctuations in GDP growth than the other tax models, with a low initial tax rate in the beginning and a high tax rate exceeding ¥180/t in 2030. Second, a large quantity of capital stock is distributed across the energy-intensive industries, which leads the existing capital investment structure to be path-dependent. This offsets the performance of carbon taxes. Third, indirect energy-intensive industries such as construction and transport are insensitive to the industrial carbon tax. Finally, comparing the impacts of the four tax rate models, the optimal industrial carbon tax for China is found to be a fixed differentiated tax rate, in which energy-intensive sectors are taxed ¥75/t and low-carbon sectors are taxed ¥50/t. [ABSTRACT FROM AUTHOR]

Research on the price fluctuation transmission of the carbon trading pilot market is of great significance for the establishment of China’s unified carbon market and its development in the future. In this paper, the carbon market transaction prices of Beijing, Shanghai, Tianjin, Shenzhen, and Guangdong were selected from December 29, 2013 to March 26, 2016, as sample data. Based on the view of the complex network theory, we construct a price fluctuation transmission network model of five pilot carbon markets in China, with the purposes of analyzing the topological features of this network, including point intensity, weighted clustering coefficient, betweenness centrality, and community structure, and elucidating the characteristics and transmission mechanism of price fluctuation in China’s five pilot cities. The results of point intensity and weighted clustering coefficient show that the carbon prices in the five markets remained unchanged and transmitted smoothly in general, and price fragmentation is serious; however, at some point, the price fluctuates with mass phenomena. The result of betweenness centrality reflects that a small number of price fluctuations can control the whole market carbon price transmission and price fluctuation evolves in an alternate manner. The study provides direction for the scientific management of the carbon price. Policy makers should take a positive role in promoting market activity, preventing the risks that may arise from mass trade and scientifically forecasting the volatility of trading prices, which will provide experience for the establishment of a unified carbon market in China. [ABSTRACT FROM AUTHOR]