| Two pakchoi cultivars of ‘Shanghaiqing’ and ‘siyueman’ was used in this experiment to studythe activity of SOD, POD, CAT and APX, the content of malondialdehyde (MDA), soluble protein,chlorophyll and glucosinolates, the conductivity, weight-loss rate during storage at differenttemperature. This will be useful to offer a theoretical basis for the use of1-MCP in preservation ofpakchoi. The results showed that:1. During storage at25℃or4℃, SOD activity decreased at first, and increased secondly,and decreased at last in both of ‘shanghaiqing’ and ‘siyueman’. The activity of CAT and PODincreased at first and then decreased, however the APX activity decreased gradually.1-MCPtreatment inhibited the decrease of SOD, CAT, APX and POD activity. The effect of1μL/L1-MCPtreatment on inhibition of SOD activity reduction was significantly better than that of0.5μL/L1-MCP treatment (P<0.05) at4℃. However, their effect on CAT activity in ‘Siyueman’ wasopposite.2. At25℃or4℃, the two varieties of MDA content, the weight-loss rate and electricalconductivity all showed a trend of increase, and their levels for storage at4℃were lower thanthat of storage at25℃.1-MCP can inhibit the increase of MDA content, weight-loss rate andelectrical conductivity. The effect of0.5μL/L1-MCP treatment on inhibition of conductivityincrease was better than that of1μL/L1-MCP treatment in ‘Shanghaiqing’, however it wasopposite for ‘Siyueman’. The variation of MDA contents was not significantly difference betweentwo treatments of1-MCP at25℃or4℃. The content of soluble protein and chlorophyll showed atrend of declining, and both of them decreased more slowly at4℃than that of25℃.1-MCPcould effectively inhibit the decrease of soluble protein and chlorophyll content for both cultivars.Different concentration of1-MCP treatment showed no significant difference of soluble proteincontent. But1-MCP concentration had influence on the chlorophyll content of ‘Shanghaiqing’, butno effect on ‘Siyueman’.3. When treated with0.5μL/L1-MCP at25℃, the glucosinolate content of ‘Shanghaiqing’increased at first and then decreased. The effect of0.5μL/L1-MCP treatment on keepment ofglucosinolate content in ‘Shanghaiqing’ was much better than that of1μL/L1-MCP treatment. The glucosinolate content of ‘Siyueman’ was higher than that of ‘Shanghaiqing’. When both cultivarswere treated with0.5μL/L1-MCP at4℃, glucosinolate content reached the highest level at thefifth day. |
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