Zhang Lei, Sun Changgang, Tian Hui, Xu Jiamin, Wu Xiuwen
Yantai Academy of Agricultural Sciences, Yantai, China.
Zhaoyuan Agricultural Technology Promotion Center, Zhaoyuan, China.
Front Plant Sci. 2024 Aug 27;15:1457694. doi: 10.3389/fpls.2024.1457694. eCollection 2024.
Boron (B), an essential micronutrient for fruit development, also plays a crucial role in maintaining the shelf life of strawberries ( Duch.) by affecting cell wall structure and components. We investigated the distribution pattern of B within cells and cell walls in strawberry fruits under different B levels and revealed the relationship between the B distribution in cell walls and fruit firmness after harvesting. Foliar spraying of 0.1% HBO promoted the growth of strawberry seedlings and improved fruit yield and flesh firmness by 45.7% and 25.6%. During the fruit softening and decay process, the content of bound B and cell wall-B decreased while more B was allocated to the protoplast and apoplast. The changes in B distribution in cells were attributed to cell damage during fruit decay, and B extended the freshness period of the fruits by alleviating the decrease of B distribution in cell walls. After leaving the fruits at room temperature for 10 h, the B content in different cell wall components significantly decreased, while foliar spraying of B alleviated the reduction of B content in covalently bound pectin (CBP), cellulose, and hemicellulose. Meanwhile, B spraying on fruit decreased the activity of cell wall degradation enzymes, including polygalacturonase (PG) and pectin lyase (PL), by 20.2% and 38.1%, while enhancing the demethylation of pectin by increasing pectin methylesterase (PME) activity from 21.6 U/g to 25.7 U/g. Thus, foliar spraying of 0.1% HBO enhances the cross-linking of B with cell wall components and maintains cell wall structure, thereby prolonging the shelf life of strawberry fruits.
硼（B）是果实发育必需的微量营养元素，通过影响细胞壁结构和成分，在维持草莓（Fragaria × ananassa Duch.）的货架期方面也起着关键作用。我们研究了不同硼水平下草莓果实细胞和细胞壁内硼的分布模式，并揭示了收获后果实细胞壁中硼的分布与果实硬度之间的关系。叶面喷施0.1% HBO促进了草莓幼苗的生长，使果实产量和果肉硬度分别提高了45.7%和25.6%。在果实软化和腐烂过程中，结合态硼和细胞壁硼的含量下降，而更多的硼被分配到原生质体和质外体中。细胞中硼分布的变化归因于果实腐烂过程中的细胞损伤，硼通过减轻细胞壁中硼分布的减少来延长果实的保鲜期。果实室温放置10小时后，不同细胞壁成分中的硼含量显著下降，而叶面喷施硼缓解了共价结合果胶（CBP）、纤维素和半纤维素中硼含量的降低。同时，对果实喷施硼使细胞壁降解酶（包括多聚半乳糖醛酸酶（PG）和果胶裂解酶（PL））的活性分别降低了20.2%和38.1%，同时通过将果胶甲酯酶（PME）活性从21.6 U/g提高到25.7 U/g增强了果胶的去甲基化作用。因此，叶面喷施0.1% HBO增强了硼与细胞壁成分的交联，维持了细胞壁结构，从而延长了草莓果实的货架期。
