以接近成熟的低成熟度果实为实验材料,以果皮塌陷指数、变色指数以及与细胞膜相关的物质为测定指标,围绕果实膜脂降解途径展开,研究橙油处理致柑橘果实油胞病对果皮膜脂代谢的影响。结果表明,橙油处理可引起柑橘油胞病的发生,病症随贮藏时间的延长而加剧;橙油对果皮具有光毒性,细胞膜系统参与果实对油胞病的响应。橙油处理致油胞病使得磷脂酶D活性增加,磷脂酰胆碱、磷脂酰肌醇含量下降,磷脂酸含量上升,表明细胞膜水解加剧。发病早期脂氧合酶活性高于健康果实,使得果皮脂肪酸不饱和度下降,活性氧急剧产生,膜脂发生过氧化反应;过量的活性氧攻击细胞膜使得丙二醛含量和相对电导率持续上升;细胞膜结构和功能受损,从而促使油胞病发生并加剧油胞病症状。橙油致柑橘果实油胞病机制的明确为进一步研究柑橘油胞病及其防控措施提供了理论依据。
The effects of oleocellosis induced by orange oil on the membrane lipid metabolism of Navel orange at low ripening stage(nearly ripe) were studied based on collapse index,discoloration index and cell membrane-related substances.Results showed that oil treatment could induce oleocellosis in Navel orange and the severity of oleocellosis increased as time prolonged.Orange oil exerted phototoxic effects on the fruit peel; the cell membrane system was involved in the response of the fruit to oleocellosis.Oil treatment increased phospholipase D(PLD) activity,decreased phosphatidylcholine(PC) and phosphatidylinositol(PI) and enhanced phosphatidic acid(PA) contents,indicating that the severity of cell membrane degradation increased as oleocellosis developed.Lipoxygenase(LOX) activity was also enhanced by oil treatment during the early storage period,thereby leading to the decrease of unsaturated/saturated fatty acid ratio and the accumulation of reactive oxygen species(ROS).Malondialdehyde(MDA) and electrolyte leakage were increased due to the increased contents of hydrogen peroxide(H_2O_2) and superoxide anion(O_2~-·) during the whole storage.Cell membrane damage contributed to the occurrence of oleocellosis and led to the increase of oleocellosis severity during storage.This study could provide a theoretical reference for exploring the mechanisms and control strategies of oleocellosis.