Culture of Seashore Mallow under Different Salinity Levels Using Plastic Nutrient-Rich Matrices and Transplantation

Emergence and early seedling growth are critical for establishing reasonable plant population densities under saline stress conditions. An experiment with seashore mallow (Kosteletzkya virginica L.) seedling culture in plastic nutrient-rich matrices and transplanted into pots filled with soil from a local farm field was conducted under five salinity levels (0, 0.3, 0.6, 0.9, and 1.2%). Emergence, survival, growth, and physiological characteristics were monitored for 45 d after seeding. Increasing salinity levels from 0.3 to 1.2% inhibited seedling growth through the reduction in leaf size, leaf number, and physiological traits. At 45 d after seeding, there was a reduction of 13 to 47% in photosynthesis, 18 to 62% in soluble protein, 6 to 84% in superoxide dismutase activity, and 20 to 81% in root activities, whereas free amino acids increased by 34 to 104%, proline by 18 to 167%, and malondialdehyde by 20 to 220%. The reduction in photosynthesis was mainly associated with the reduction in stomatal conductance. Emergence and survival rates could be maintained at >= 60% at salinity levels <= 0.9%. Our results indicate that seashore mallow could grow in saline soils with seedling culture in nutrient-rich plastic matrices and transplanted into conventional soils provided that the salinity levels in nutrient-rich medium and conventional soils are <= 0.9%.