Salinity Stress in Legume Crops: A Comprehensive Review of Effects, Mechanisms, and Mitigation Strategies

Abstract

Salinity stress poses a significant challenge to global crop production, particularly in regions relying heavily on irrigation. This review explores the detrimental impacts of salt stress on grain legumes, crucial plants renowned for their high protein content and nitrogen-fixing ability. The increasing use of saline groundwater and the accumulation of soil salts threaten the sustainability of legume cultivation worldwide. Salt stress disrupts fundamental physiological processes in legumes, including photosynthesis, hormone regulation, and nutrient uptake, resulting in substantial reductions in yield and quality. It exacerbates osmotic stress and ion toxicity, severely compromising plant health and productivity. Understanding the intricate mechanisms underlying salt tolerance in grain legumes is pivotal for developing effective mitigation strategies. This review synthesizes current knowledge on the tolerance mechanisms employed by legumes to cope with salt stress. It examines various management approaches aimed at enhancing their resilience under saline conditions. Key findings highlight that salt stress can lead to over 70% reductions in growth and variable decreases in yield and mineral absorption rates. Innovative strategies such as genetic engineering of transgenic varieties and advanced crop management practices offer promising avenues to enhance salt tolerance and boost legume productivity on salinity-affected soils. Furthermore, insights into mechanisms such as ion compartmentalization and ion excretion provide critical pathways for developing salt-resistant legume cultivars.  Apoplastic acidification emerges as a reliable indicator of salt stress resistance in these plants. By elucidating these mechanisms and strategies, this review contributes to the ongoing efforts aimed at safeguarding legume production and global food security in the face of escalating salinity stress.