Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Department of Food Science and Technology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
Food Res Int. 2022 Jul;157:111219. doi: 10.1016/j.foodres.2022.111219. Epub 2022 Apr 8.
Akebia trifoliata fruit cracks easily, but little is known about the underlying mechanism of this process. In this study, the changes in minerals contents, water distribution, phytohormone levels, and reactive oxygen species (ROS) metabolism were investigated to explore the effects of cell-wall metabolism in A. trifoliata fruit cracking. The micro-morphological observation confirmed that A. trifoliata fruit cracking was closely related to the cell-wall metabolism. After cracking, the higher polygalacturonase, β-1,4-endoglucanase, and β-glucosidase activities resulted in the depolymerization of covalently bound pectin (from 9.69% to 7.70%) and cellulose (from 57.91% to 38.05%). Moreover, the disordered ROS homeostasis resulted from the lower superoxide dismutase and ascorbate peroxidase activities, which led to cellular oxidative damage. These modifications, together with the decreases in Ca, K, and B, degradation of starch, and the movement of water, decreased cell-wall strength and degraded the cellulose network, and thus resulted in A. trifoliata cracking. The above processes were regulated by phytohormones through increased indole-3-acetic acid, salicylic acid, and jasmonic acid levels, as well as decreased cytokinin content. The findings of this study will be beneficial for further research into the preservation of A. trifoliata fruit, which is of great significance to the development of the A. trifoliata industry.
三叶木通果实容易开裂，但对于其开裂机制知之甚少。本研究调查了矿物质含量、水分分布、植物激素水平和活性氧（ROS）代谢的变化，以探讨细胞壁代谢对三叶木通果实开裂的影响。微观形态观察证实，三叶木通果实开裂与细胞壁代谢密切相关。开裂后，较高的多聚半乳糖醛酸酶、β-1,4-内切葡聚糖酶和β-葡萄糖苷酶活性导致共价结合果胶（从 9.69%降至 7.70%）和纤维素（从 57.91%降至 38.05%）的解聚。此外，超氧化物歧化酶和抗坏血酸过氧化物酶活性降低导致 ROS 平衡失调，引起细胞氧化损伤。这些变化，加上 Ca、K 和 B 的减少、淀粉的降解以及水分的移动，降低了细胞壁的强度并降解了纤维素网络，导致三叶木通开裂。这些过程通过增加吲哚-3-乙酸、水杨酸和茉莉酸水平以及降低细胞分裂素含量被植物激素调节。本研究的发现将有助于进一步研究三叶木通果实的保存，这对三叶木通产业的发展具有重要意义。
