Salt marshes are important blue carbon ecosystems that efficiently capture and store atmospheric CO₂, contributing significantly to coastal carbon sequestration. However, their habitats have been severely degraded by land reclamation, coastal development, and climate change, indicating the need for restoration.
This study investigated the growth and salt tolerance of Suaeda japonica, a major salt marsh plant in Korea, and evaluated the effects of Sargassum horneri extract (SHE) as a natural biostimulant to determine optimal treatment conditions for plant growth under saline stress.
Seedlings were cultivated outdoors for 70 days under three SHE concentrations (0, 0.1, and 0.5 g L⁻¹) and four NaCl levels (0, 100, 200, and 300 mM). Growth characteristics, pigment contents, oxidative stress indicators, and antioxidant enzyme activities were comprehensively measured to assess physiological responses.
The results showed that SHE treatment enhanced growth and photosynthetic pigment stability, while reducing salt-induced oxidative damage in S. japonica. These findings suggest that SHE can improve the resilience and establishment of salt marsh plants, highlighting its potential application in sustainable salt marsh restoration.
A summary of growth responses of S. japonica under different salinity and SHE treatments is presented in Figure 1.