Chen Mingmin, Gu Hui, Wang Lirong, Shao Yuanzhi, Li Rui, Li Wen
School of Horticulture, Hainan University, Haikou, China.
Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province, Hainan University, Haikou, China.
Front Nutr. 2022 May 20;9:911542. doi: 10.3389/fnut.2022.911542. eCollection 2022.
Due to geographical location and climatic factors, postharvest storage and preservation of tropical fruits and vegetables are still facing huge challenges. Ethephon (ETH) is widely used as an ethylene donor to achieve the commercial color and flavor of climacteric fruits. However, the effect of ETH on fruit coloration was affected by many factors, such as fruit species, plant hormones, and storage conditions. In this study, the main mango variety "Guifei" in Hainan, China, was used to study the effects of different concentrations of ETH on fruit ripening and coloration during storage at 25°C. Results showed that postharvest treatment with ETH (300, 500, and 900 mg·L) enhanced the activities of ACS and ACO, stimulated the release of endogenous ethylene, and accelerated fruit softening and color transformation. Compared with control, ETH treatment not only accelerated the breakdown of chlorophyll with higher activities of Chlase and MDCase but also induced the synthesis of carotenoid and anthocyanin with higher activities of PAL, CHI, DFR, and UFGT. Moreover, the changes in DFR and UFGT activities coincided with the increase in ETH concentration. Further, correlation analysis showed that the production of endogenous ethylene induced by ETH was significantly negatively correlated with firmness and chlorophyll content, whereas positively correlated with MDA content and anthocyanin content. This study suggests that the positive effect of ETH on "Guifei" mango color transformation is concentration-dependent within a certain concentration range. Anthocyanin is the main pigment for the red formation of "Guifei" mango, and DFR and UFGT may play critical roles in anthocyanin synthesis. ETH promoted the red coloration by promoting the release of endogenous ethylene and enhancing the activities of anthocyanin synthesis enzymes.
由于地理位置和气候因素，热带水果和蔬菜的采后贮藏和保鲜仍面临巨大挑战。乙烯利（ETH）作为一种乙烯供体被广泛用于实现跃变型果实的商业色泽和风味。然而，ETH对果实着色的影响受多种因素制约，如果实种类、植物激素和贮藏条件等。本研究以中国海南主栽芒果品种“贵妃”为试材，研究25℃贮藏期间不同浓度ETH对果实成熟和着色的影响。结果表明，采后用ETH（300、500和900mg·L）处理可提高ACS和ACO活性，刺激内源乙烯释放，加速果实软化和颜色转变。与对照相比，ETH处理不仅通过较高的叶绿素酶和苹果酸脱氢酶活性加速叶绿素分解，还通过较高的苯丙氨酸解氨酶、查尔酮异构酶、二氢黄酮醇4-还原酶和UDP-葡萄糖：类黄酮3-O-葡萄糖基转移酶活性诱导类胡萝卜素和花青素合成。此外，DFR和UFGT活性的变化与ETH浓度的增加一致。进一步的相关性分析表明，ETH诱导的内源乙烯产生与硬度和叶绿素含量呈显著负相关，而与丙二醛含量和花青素含量呈正相关。本研究表明，在一定浓度范围内，ETH对“贵妃”芒果颜色转变的积极作用具有浓度依赖性。花青素是“贵妃”芒果红色形成的主要色素，DFR和UFGT可能在花青素合成中起关键作用。ETH通过促进内源乙烯释放和增强花青素合成酶活性促进红色着色。
