Effects of salt stress on root growth and nutrient absorption efficiency of different salt-tolerant summer maize varieties

Coastal saline-alkali land, as one of the most promising types of medium- and low-yield fields in China, plays a critical role in tapping the potential of grain production. Salinity significantly affects the distribution and function of maize roots, thereby influencing water and nutrient uptake. Understanding the effects of salt stress on root growth and nutrient absorption in maize varieties with differing salt tolerance provides a theoretical and technical foundation for high-yield, stress-resilient maize cultivation in saline-alkali soils. In this study, both pool culture and soil column experiments were conducted using two maize varieties—Wansheng 69 (WS69, salt-tolerant) and Denghai 605 (DH605, salt-sensitive). Three salinity treatments were applied: control (CK, no salt), medium salinity stress (MS, 1.5‰), and high salinity stress (HS, 3.0‰). The effects of salt stress on root growth, nutrient uptake, plant nutrient accumulation, and yield were comprehensively evaluated. Results showed that, compared with CK, salt stress disrupted the antioxidant enzyme metabolism in maize roots, reduced root activity, inhibited root growth, and impaired nutrient uptake and utilization, ultimately leading to reduced nutrient accumulation, shoot dry matter, and yield. Yield reduction in the salt-tolerant variety (6.90%-9.12%) was significantly lower than that in the salt-sensitive variety (16.12%-27.42%). Under high salinity, WS69 exhibited significantly higher antioxidant enzyme (SOD, POD, CAT) activities, lower malondialdehyde (MDA) content, lower root respiration rate, and greater root length, surface area, and volume compared to DH605. These traits helped maintain nutrient absorption, promoted dry matter accumulation, and conferred stronger adaptability. In conclusion, salt stress inhibits root growth and yield formation. Salt-tolerant maize varieties can maintain antioxidant enzyme activity and root vitality under salt stress—especially under high salinity—thereby supporting root growth and yield stability, with relatively lower yield losses.