2,4-表油菜素内酯处理对不同温度贮藏中小白菜品质和生理生化的影响

Effects of 2,4-Epibrassinolide Treatment on Quality,Physiology and Biochemistry of Pakchoi(Brassica chinensis L.) during Storage at Different Temperatures

以‘上海青’小白菜为试验材料,采用1.0 mg/L的2,4-表油菜素内酯(2,4-epibrassinolide, EBR)溶液进行采后喷洒处理,分别于2℃和20℃下贮藏,研究EBR处理对贮藏期间小白菜品质和生理生化的影响。结果显示,EBR处理能抑制2℃和20℃贮藏期间小白菜的L*上升和色调角H下降,减缓总叶绿素、叶绿素a和叶绿素b含量的减少,贮藏结束时小白菜总叶绿素含量分别比对照高5.57%和46.25%。EBR处理有效地抑制了小白菜在2℃和20℃贮藏期间叶绿素降解相关酶(叶绿素酶、脱镁螯合酶和脱镁叶绿素水解酶)活性的上升,贮藏结束时三种酶活性均低于对照28%以上。EBR处理减弱了2℃和20℃贮藏期间小白菜的呼吸强度,抑制其抗氧化酶(超氧化物歧化酶、过氧化氢酶和抗坏血酸过氧化物酶)活性的下降,降低了膜脂过氧化酶(过氧化物酶和脂氧合酶)活性,并抑制超氧阴离子、过氧化氢和丙二醛含量的上升,贮藏结束时两温度下EBR处理小白菜丙二醛含量分别较对照降低了8.91%和19.18%。结果表明,小白菜2℃贮藏较20℃贮藏更能维持其较好的品质和生理生化指标;1.0 mg/L EBR处理可以有效延缓2℃和20℃贮藏期间小白菜黄化,减少品质和生理的下降,其中对20℃贮藏条件小白菜各指标的影响更为明显。

’Shanghaiqing’ was sprayed with 1.0 mg/L EBR solution and stored at 20 ℃ and 2 ℃ respectively to study the effects of EBR on the quality,physiology and biochemistry of pakchoi after postharvest.The results showed that EBR treatment could inhibit the increase of L* and the decrease of hue angle H of pakchoi during storage at 2 ℃ and 20 ℃,and slow down the decrease of total chlorophyll,chlorophyll a and chlorophyll b content.At the end of storage,the total chlorophyll content of pakchoi was 5.57% and 46.25% higher than that of the control at 2 ℃ and 20 ℃ respectively.EBR treatment significantly inhibited the increase of chlorophyll degradation related enzymes(chlorophyllase,Mg-dechelatase and pheophytin pheophorbide hydrolase) of pakchoi during storage at 2 ℃ and 20 ℃,the activities of the three enzymes were more than 28% lower than those of the control at the end of storage.EBR treatment weakened the respiratory intensity of pakchoi,inhibited the decrease of the activities of antioxidant enzymes(superoxide dismutase,catalase and ascorbate peroxidase),decreased the activity of membrane lipid peroxidase(peroxidase and lipoxygenase),and inhibited the increase of superoxide anion,hydrogen peroxide and malondialdehyde content of pakchoi during storage at 2 ℃ and 20 ℃.At the end of storage,the malondialdehyde content of EBR treatment decreased by 8.91% and 19.18%,respectively,compared with the control.The results showed that pakchoi stored at 2 ℃ could maintain better quality and physiological and biochemical indexes than storage at 20 ℃.1.0 mg/L EBR treatment could effectively delay the yellowing of pakchoi during storage at 2 ℃ and 20 ℃,and reduce the decline of quality and physiology,among them,the effect on the indexes of pakchoi stored at 20 ℃ was more obvious.