April 1975 on a few of the 1974 experiments to obtain overwinter chan- 

 ges in first-year plantings, and to better evaluate these treatments 

 for shoreline protection. 



3 . Laboratory Studies . 



All plants used in the laboratory experiments were germinated from 

 seed collected in 1972 at Oregon Inlet, North Carolina. The seeds 

 were stored in seawater (2- to 3-percent salt) at 2° to 3° Celsius. 

 Before germination, the seeds were immersed 10 minutes in a 25-percent 

 clorox solution, rinsed thoroughly in distilled water, and placed in 

 a fungicide solution (0.25 gram of Thiram-75 [tetramethylthiuramidi- 

 sulfide] per 100 milliliters for 5 minutes). The seeds were removed 

 without rinsing and scattered evenly on a tray over paper towels 

 saturated with a 10"'* molar solution of calcium sulfate (CaSOi^) . The 

 tray containing the seed was covered with saran to minimize evaporation 

 and to allow light to reach the seed; small slits in the saran allowed 

 air exchange. The tray was placed in an environment with a diurnal 

 photo period of 14 hours' daylight and 10 hours' darkness until germina- 

 tion (about 1 week) . Seedlings were selected from the tray for 

 transfer to a hydroponic culture when they had a 4-centimeter-high 

 green shoot and two roots 5 to 10 millimeters long. 



Table 1. Nutrient solutions employed for nitrogen source and aeration 

 experiments with Spartina altemiflora. 



Treatment 



Saltl 



Concentration 











Basic medium 





Magnesium sulfate 



MgSO^ 



0.25 mM 



Calcium chloride 



CaCl2 



1.50 m!-1 



Potassium phosphate 



KH2P0it 



0.25 mM 



Sodium chloride 



NaCl 



85.30 mM 



Calcium carbonate 



CaC03 



0.50 g L-^ 



Ferric ethylene diamine 







tetraacetate 



FeEDTA^ 



0.90 mg L"l 



Nitrogen variables added to basic medium 



Ammonium chloride 



NHt^Cl 



4.0 mM 



Potassium chloride 



KCl 



4.0 mM 



Potassium nitrate 



KNO3 



4.0 mM 



Ammonium chloride 



NH4CI 



2.0 mM 



Potassium nitrate 



KNO3 



2.0 mM 



Potassium chloride 



KCl 



2.0 mM 









1. Micronutrients added at one-half the concentration given by 

 Hoagland and Arnon (1950) . 



2. Added every 5 days. 



14 



