[Objective] Pericarp browning in the postharvest litchi significantly reduced its commercial value and limited the expanding of litchi markets. Physiological changes during the process of pericarp browning were determ...[Objective] Pericarp browning in the postharvest litchi significantly reduced its commercial value and limited the expanding of litchi markets. Physiological changes during the process of pericarp browning were determined in order to identify the underlying mechanisms. [Method] Matured Feizixiao fruits were stored at 25 ℃ and 70%±5% relative humidity. The physiological changes happened in pericarp during storage were tested at an 8-hour interval. [Result] The fruit of Feizixiao (Litchi chinensis Sonn. cv Feizixiao) turned completely brown within 72 h after being harvested under the experimental conditions. Sharp increase of the browning index occurred from 48 to 64 hours after harvest (HAH). With the browning of pericarp,water content of the whole fruit and pericarp decreased continuingly. In contrast,there were no significant changes in the water content of pulp during the same period. MDA content,pH value and relative leakage rate of pericarp were increased during storage. Most of pigment contents including anthocyanin,flavonoid,phenols,chlorophyll a and total chlorophyll decreased. POD activity was initially increased in 32 HAH and then decreased afterwards. PPO activity was decreased continuously,while the activities of catalase and superoxide dismutase exhibited the pattern of 'increasing-decreasing-increasing' as the storage time progressed. Correlation,stepwise regression and path analyses showed that water loss of pericarp was the major factor of pericarp browning. Principal and cluster analyses showed that there were two stages of pericarp browning during the course of litchi storage. [Conclusion] Water status of pericarp was the most important factor affecting pericarp browning. The pericarp browning happened by stages,which was mainly determined by the water loss of pericarp.展开更多
This paper analyzes whether the slowdown of China＇s trade in 2012-2015 was cyclical or structural, and further discusses the effects of structural factors, including trade structure, trade protectionism and global va...This paper analyzes whether the slowdown of China＇s trade in 2012-2015 was cyclical or structural, and further discusses the effects of structural factors, including trade structure, trade protectionism and global value chain participation, Using the national panel data from 2000 to 2015, based on the error correction model and import-intensity- adjusted demand model, our results show that the slowdown of China＇s trade growth in 2012-2015 was mainly a result of cyclical factors. Using 2000-2015 industry- level data, we also find that the structure of trade goods had an inhibitory effect on the import slowdown but a positive effect on the export slowdown. Trade protectionism had an adverse effect on the trade growth slowdown. The global value chain participation marginally contributed to the slowdown in trade growth. Therefore, the impacts of structural factors on trade growth slowdown cannot be ignored, and related policies should receive greater attention from policy-makers.展开更多
基金Supported by National Science Foundation of China ( GrantNo.30460085, 30960233)Open Foundation of Provincial Key Laboratory for Fruit and Vegetable Preservation of Hainan ( GrantNo. CH001)National Non-profit Institute Grant (ITBBZD2007-3-1)~~
文摘[Objective] Pericarp browning in the postharvest litchi significantly reduced its commercial value and limited the expanding of litchi markets. Physiological changes during the process of pericarp browning were determined in order to identify the underlying mechanisms. [Method] Matured Feizixiao fruits were stored at 25 ℃ and 70%±5% relative humidity. The physiological changes happened in pericarp during storage were tested at an 8-hour interval. [Result] The fruit of Feizixiao (Litchi chinensis Sonn. cv Feizixiao) turned completely brown within 72 h after being harvested under the experimental conditions. Sharp increase of the browning index occurred from 48 to 64 hours after harvest (HAH). With the browning of pericarp,water content of the whole fruit and pericarp decreased continuingly. In contrast,there were no significant changes in the water content of pulp during the same period. MDA content,pH value and relative leakage rate of pericarp were increased during storage. Most of pigment contents including anthocyanin,flavonoid,phenols,chlorophyll a and total chlorophyll decreased. POD activity was initially increased in 32 HAH and then decreased afterwards. PPO activity was decreased continuously,while the activities of catalase and superoxide dismutase exhibited the pattern of 'increasing-decreasing-increasing' as the storage time progressed. Correlation,stepwise regression and path analyses showed that water loss of pericarp was the major factor of pericarp browning. Principal and cluster analyses showed that there were two stages of pericarp browning during the course of litchi storage. [Conclusion] Water status of pericarp was the most important factor affecting pericarp browning. The pericarp browning happened by stages,which was mainly determined by the water loss of pericarp.
文摘This paper analyzes whether the slowdown of China＇s trade in 2012-2015 was cyclical or structural, and further discusses the effects of structural factors, including trade structure, trade protectionism and global value chain participation, Using the national panel data from 2000 to 2015, based on the error correction model and import-intensity- adjusted demand model, our results show that the slowdown of China＇s trade growth in 2012-2015 was mainly a result of cyclical factors. Using 2000-2015 industry- level data, we also find that the structure of trade goods had an inhibitory effect on the import slowdown but a positive effect on the export slowdown. Trade protectionism had an adverse effect on the trade growth slowdown. The global value chain participation marginally contributed to the slowdown in trade growth. Therefore, the impacts of structural factors on trade growth slowdown cannot be ignored, and related policies should receive greater attention from policy-makers.
