Table 1.

Nitrogen starvation and excess stress effects on the root morphology and physiology of walnut seedlings.

Treatment	Surface area	Volume	Fractal dimension	Proline content	Malondialdehyde content	Total nitrogen content
	Cm2	Cm3		µg/g	nmol/g	g/kg
EL	460.90 ± 8.2024 a	67.38 ± 3.0710 a	1.61 ± 0.0055 a	435.38 ± 3.6660 b	27.28 ± 0.2345 b	26.66 ± 0.3959 b
L	274.44 ± 2.8425 c	36.67 ± 0.8851 b	1.56 ± 0.0203 b	419.81 ± 5.7013 b	25.14 ± 0.2022 c	29.40 ± 0.5243 a
H	360.52 ± 7.9209 b	68.10 ± 2.5963 a	1.65 ± 0.0057 a	490.90 ± 5.1761 a	28.21 ± 0.0517 a	30.24 ± 0.6002 a

The first column lists the different treatments (L = control, EL = nitrogen starvation, H = nitrogen excess), while the top row shows the indicators and the second row shows the indicator units. The data are the means ± SE. Different letters indicate statistical significance between the treatments tested by the analysis of variance (P < 0.05).