2.1 Plant Material
Seeds of Spartina alterniflora (SA ) were collected fromSan-San Lake in South East Shanghai city at the end of November in 2015 and 2016. The cleaned spikelets were stored in wet tissue (cloth) in sealed plastic at 4°C in the refrigerator. SA mature seeds require two to three months, after-ripening, wet storage in cold (stratification) to break dormancy (Garbisch & McIninch, 1992) and they remain viable for about one year. Seeds of SV were rinsed several times with tap water and then transferred to Petri-dishes and covered with water till germinate. After germination, they were transferred into potted soil. When the young seedlings of SA were about 2 cm in length and started greening, they were removed from the glass petri dishes. Trays containing SA seedlings were kept indoor at a temperature between 25~27°C, under fluorescent light at a PPFD of 80 - 120 μmol m-2 s-1 with a photoperiod of 16/8 hour (light/dark). Two-month old healthy plants with large expanded leaves where transferred to a hydroponic system for salt treatment. For SV , dry seeds were directly sown into wet potted soil, which was maintained wet by spraying water daily on the soil till the seeds germinated. SV grew under the same photoperiod and temperature conditions as SA . Nutrient was added routinely to ensure healthy growing plants before transferring them to hydroponic medium for salt stress treatment.