NaCl treatment markedly enhanced pollen viability and pollen preservation time of euhalophyte Suaeda salsa via up regulation of pollen development-related genes

Vegetable growth of halophytes has significantly increased through moderate salinity. However, little is known about the reproductive traits of euhalophytes. Male reproduction is pivotal for fertilization and seed production and sensitive to abiotic stressors. The pollen viability and pollen longevity of Suaeda salsa treated with 0 and 200 mM of NaCl were evaluated. It was revealed that the pollen size of S. salsa treated with NaCl was significantly bigger than that in controls. Furthermore, the pollen viability of S. salsa plants treated with NaCl was also significantly higher than that of control after 8 h of the pollens were collected (from 10 to 27 h). The pollen viability of NaCl-treated plants in the field could be maintained for 8 h (from 07:00 to 15:00) in sunny days, which was 1 h longer than that of control plants (from 07:00 to 14:00). Meanwhile, the pollen preservation time of NaCl-treated plants was 16 h at room temperature, which was 8 h longer than that of control plants. Genes related to pollen development, such as SsPRK3, SsPRK4, and SsLRX, exhibited high expression in the flowers of NaCl-treated plants. This indicated that NaCl markedly improved the pollen viability and preservation time via the increased expression of pollen development-related genes, and this benefits the population establishment of halophytes such as S. salsa in saline regions.