Nabi Farhan, Sarfaraz Ahmed, Kama Rakhwe, Kanwal Razia, Li Huashou
College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510643, China.
School of Life Sciences and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Plants (Basel). 2025 Jun 22;14(13):1916. doi: 10.3390/plants14131916.
Humic acid (HA), a major component of soil organic matter, is a naturally occurring macromolecule formed through the decomposition of plant and microbial residues. Its molecular structure comprises functional groups such as carboxyl, phenolic, hydroxyl, and carbonyl functional groups, which enable HA to interact with soil particles, nutrients, and biological systems. These interactions significantly contribute to soil fertility and overall plant productivity. Functionally, HA enhances soil health by increasing cation exchange capacity, improving water retention, and promoting the formation and stabilization of soil aggregates. In addition to its role in soil conditioning, HA is essential in mitigating plant stress. It achieves this by modulating antioxidant enzyme activity, stabilizing cellular membranes, and alleviating the adverse effects of abiotic stressors such as salinity, drought, and heavy metal toxicity. This review highlights the structural characteristics of HA, its structure-based functions, and the mechanisms involved in plant stress alleviation. Additionally, we explore how HA can be modified through physical, chemical, and biological approaches to enhance its agronomic performance. These modifications are designed to improve HA agronomic efficiency by increasing nutrient bioavailability, reducing environmental losses through minimized leaching and volatilization, and supporting sustainable agricultural practices. Overall, this review underscores the multifaceted roles of HA in promoting plant resilience to environmental stress, highlighting its potential as a key agent in the development of sustainable and eco-friendly crop production systems.
腐殖酸（HA）是土壤有机质的主要成分，是一种通过植物和微生物残体分解自然形成的大分子。其分子结构包含羧基、酚羟基、羟基和羰基等官能团，这些官能团使HA能够与土壤颗粒、养分和生物系统相互作用。这些相互作用对土壤肥力和植物整体生产力有显著贡献。在功能方面，HA通过增加阳离子交换能力、改善保水性以及促进土壤团聚体的形成和稳定来增强土壤健康。除了在土壤改良中的作用外，HA在缓解植物胁迫方面也至关重要。它通过调节抗氧化酶活性、稳定细胞膜以及减轻盐度、干旱和重金属毒性等非生物胁迫因素的不利影响来实现这一点。本综述重点介绍了HA的结构特征、基于结构的功能以及植物胁迫缓解所涉及的机制。此外，我们探讨了如何通过物理、化学和生物学方法对HA进行改性，以提高其农艺性能。这些改性旨在通过提高养分生物有效性、通过最小化淋溶和挥发减少环境损失以及支持可持续农业实践来提高HA的农艺效率。总体而言，本综述强调了HA在促进植物对环境胁迫的恢复力方面的多方面作用，突出了其作为可持续和生态友好型作物生产系统发展中的关键因素的潜力。
