Table 2.

Effects of the homogeneous or heterogeneous N supply on shoot and root biomass and respiration of fine roots of P. tremuloides measured in the greenhouse experiment (n.s., not significant; P > 0.05). See Figure 1 for a graphical explanation of treatment application.

Treatment	Homogeneous N supply				Heterogeneous N supply
	N1	N3	N10	P	N1 (N3)	N3 (N1)	P	N1 (N10)	N10 (N1)	P
Shoot DW (g plant−1)
Mean	8.78	14.93	14.09		n.s.	16.49			10.02	n.s.
SE	4.94	5.48	7.68			3.67			5.34
Root DW (g plant−1)
Mean	13.33	12.58	14.30	n.s.	5.74	6.58	n.s.	4.51	6.77	n.s.
SE	7.65	3.54	6.04		3.22	3.81		2.24	4.42
Fine root age (days)
Mean	63	53	54		59	60		50	48
Respiration per unit biomass (nmol O2 g−1 DW s−1)
Mean	6.70	6.83	6.72	n.s.	5.45	6.52	n.s.	7.30	7.42	n.s.
SE	0.78	0.77	0.75		1.08	1.02		1.13	1.18
Respiration per unit N (nmol O2 g−1 N s−1)
Mean	354.8	308.0	244.3	n.s. (0.06)	298.0	316.5	n.s.	347.2	293.7	n.s. (0.06)
SE	33.2	32.5	32.0		52.0	48.8		50.7	52.7