Growth Responses and Nitrogen Uptake by Saltgrass (Distichlis spicata L.), a Halophytic Plant Species, under Salt Stress, Using the ¹⁵N Technique

Table 6

Total nitrogen concentration (mg g⁻¹) and atom percent ¹⁵N of various clones of saltgrass root tissues under the control and salt (NaCl) stress conditions.

Grass clones ID	Root total N concentration		Root atom percent ^15N
	Treatment		Treatment
	Control, 0.95 dSm^−1 (608 mg L^−1)	EC 20 dSm^−1 (12,800 mg L^−1)	Control, 0.95 dSm^−1 (608 mg L^−1)	EC 20 dSm^−1 (12,800 mg L^−1)
	(mg g^−1)		(%)
240	43.02a	42.28a	2.67ab	2.64ab
A37	38.78ab	33.94c	3.01a	2.73ab
239	38.68ab	39.52ab	2.46bc	2.03c
A86	38.22ab	37.23bc	2.74ab	2.44bc
A138	37.85b	36.40bc	2.78ab	2.80ab
A60	36.96bc	36.76bc	2.89a	2.66ab
A50	36.83bc	37.45bc	2.68ab	2.67ab
A136	36.77bc	35.47bc	2.99a	2.52b
A49	36.37bc	35.19bc	2.37bc	2.36bc
A126	33.83c	33.69c	2.35c	2.07c
A107	33.00c	33.56c	2.27c	2.23c
72	32.73c	37.46bc	2.97a	2.35bc

Values are total N concentrations and atom % ¹⁵N of the roots, averages of 4 replications at the final harvest for both experiments.
Values for Total-N concentration or Atom % ¹⁵N for control and salt stress treatment columns compared together followed by the same letters are not statistically different at the 0.05 probability level.