[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
The Huang-Huai-Hai Plain is one of the typical agri-ecosystems in China,which suffers from cold damage frequently resulting in substantial economic losses.In order to monitor the changes in the occurrence of cold dama...The Huang-Huai-Hai Plain is one of the typical agri-ecosystems in China,which suffers from cold damage frequently resulting in substantial economic losses.In order to monitor the changes in the occurrence of cold damage in an effective and large-scale manner,and to determine their meteorological causes,this paper collected low temperature data from the agricultural meteorological stations and remote sensing data of MODIS from 2005 to 2015,and constructed a monitoring model of cold damage to winter wheat in Huang-Huai-Hai Plain based on the Logistic regression model.This model was used to analyze the spatio-temporal changes of cold damage of winter wheat in Huang-Huai-Hai Plain from 2011 to 2020,and correlation analysis was performed with the spatio-temporal changes of meteorological factors to ascertain how they affect cold damage.The results show that the harm from cold damage in winter wheat has been gradually decreasing from 2011 to 2020,and the cold damage areas with high probability and high frequency are moving from north to south.The meteorological elements with the greatest impacts on the degree of cold damage from stronger to weaker are heat,precipitation and sunshine duration,whose influence has spatial variability.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.
基金The National Key Research and Development Program of China(2017YD0300403)。
文摘The Huang-Huai-Hai Plain is one of the typical agri-ecosystems in China,which suffers from cold damage frequently resulting in substantial economic losses.In order to monitor the changes in the occurrence of cold damage in an effective and large-scale manner,and to determine their meteorological causes,this paper collected low temperature data from the agricultural meteorological stations and remote sensing data of MODIS from 2005 to 2015,and constructed a monitoring model of cold damage to winter wheat in Huang-Huai-Hai Plain based on the Logistic regression model.This model was used to analyze the spatio-temporal changes of cold damage of winter wheat in Huang-Huai-Hai Plain from 2011 to 2020,and correlation analysis was performed with the spatio-temporal changes of meteorological factors to ascertain how they affect cold damage.The results show that the harm from cold damage in winter wheat has been gradually decreasing from 2011 to 2020,and the cold damage areas with high probability and high frequency are moving from north to south.The meteorological elements with the greatest impacts on the degree of cold damage from stronger to weaker are heat,precipitation and sunshine duration,whose influence has spatial variability.
