Precooling and cold storage effects on antioxidant system in calla lily postharvest

ABSTRACT Low-temperature storage is one of the most effective techniques to maintain the quality and durability of cut flowers. Both quality maintenance and durability are dependent on plant metabolism factors such as antioxidant system. The objective was to evaluate the effect of low-temperature on precooling and storage after harvest, on the metabolism of calla lily [Zantedeschia aethiopica (L.) K. Spreng] concerning the antioxidant system, levels of hydrogen peroxide (H2O2), and malondialdehyde (MDA). Therefore, different storage temperatures (4 ºC and 21 ºC) were tested as well as the effect of precooling in different periods (0 to 24 hours). It was observed that the activity of catalase (CAT) and superoxide dismutase (SOD) was increased at 4 °C, as well as inflorescence durability in the commercial standard (around 12 days). At 21 °C, the content of H2O2 and MDA was higher and the visual quality reduction in the inflorescence was accelerated. Low-temperature leads to a higher activity of the enzymes of the antioxidant system (CAT and SOD) and increases postharvest longevity for calla lily. Precooling did not influence the visual quality and longevity of calla lily. Long-term exposure periods at low temperatures, with 12 and 24 hours of precooling caused stress, evidenced higher MDA levels and higher CAT activity. SOD activity was related to low temperature and shorter precooling periods resulted in better antioxidant system activity and lower MDA levels.

摘要：低温贮藏是维持切花品质与保鲜持久性最为有效的技术手段之一。切花的品质维持与保鲜持久性均依赖于抗氧化系统等植物代谢相关因子。本研究旨在评估低温对马蹄莲[Zantedeschia aethiopica (L.) K. Spreng]采后预冷及贮藏过程的影响，及其对抗氧化系统、过氧化氢（hydrogen peroxide, H₂O₂）与丙二醛（malondialdehyde, MDA）水平的代谢调控效应。试验设置4 ℃与21 ℃两种贮藏温度，并设置0至24小时不等的预冷时长，以探究其调控作用。观测结果表明，4 ℃环境下过氧化氢酶（catalase, CAT）与超氧化物歧化酶（superoxide dismutase, SOD）活性显著升高，同时花序保鲜寿命达到商业标准要求（约12天）；而21 ℃条件下，H₂O₂与MDA含量更高，花序外观品质的退化速度显著加快。低温可提升抗氧化系统酶类（CAT与SOD）的活性，进而延长马蹄莲的采后寿命。预冷处理未对马蹄莲的外观品质与保鲜寿命产生显著影响，但12小时与24小时的长期低温预冷会引发胁迫，表现为MDA水平升高与CAT活性增强。SOD活性与低温环境呈正相关，且较短的预冷周期可提升抗氧化系统活性，降低MDA的积累水平。