Growth Responses of Seashore Paspalum to Sodium Chloride Stress.

Two cultivars (Aloha and Sea Dwarf) of Seashore paspalum (Paspalum vaginatum Swartz) were studied in a greenhouse to evaluate their growth responses in terms of shoot and root lengths, shoot (clippings) fresh and DM weights and the grass general quality under salinity stress. Grasses were grown hydroponically using Hoagland solution No. 1 salinized with sodium chloride to salinity levels of 15,000, 30,000, 45,000, and 60,000 mg L^-1 NaCl. Four replications of each treatment were used in a RCB design in this study. Grasses were grown at these salinity levels for 6 weeks. During this period, the shoots were harvested weekly. Prior to each harvest, shoot and root lengths were measured and recorded, and grass general quality was also evaluated. The harvested clippings fresh weights were weighed and recorded. The clippings were then oven-dried at 65° C and DM weights recorded. At the last harvest, roots were also harvested and fresh weights determined, then oven-dried at 65°C and DM weights were recorded. The results showed no difference in the shoot or root lengths and clippings fresh and DM weights of either cultivar at the first (15,000 mg L^-1 NaCl) salinity level. However, the measured parameters significantly decreased at the 30,000 mg L^-1 NaCl salinity level compared to that of the control. The grass growth ceased at the higher (45,000 and 60,000 mg L^-1 NaCl) salinity levels. No grass survived at the highest (60,000 mg L^-1 NaCl) salinity level. At each salinity level, there were some numerical differences found in the shoot and root lengths as well as fresh and DM weights of the two cultivars. Under any salinity level, the root lengths of both cultivars were less severely affected than that of the shoot. Grass general qualities followed the same pattern as the grass fresh and DM weights under salinity stress.