Table 1.

Dry weight and number of cluster roots of hydroponically grown Hakea actites

N source	Concentration (μM)	Dry weight					No. of cluster roots per pot
		Shoot (g)	Roots (g)	Cluster roots (mg)	Cluster root (% of root dry weight)	Total biomass (g)	13 weeks	22 weeks	23 weeks	24 weeks	25 weeks	26 weeks
No N	0	1.8±0.14a	0.75±0.08a	100±66b	11.4±6.2	2.7±0.2a	1.3±0.9	3.0±0.6	3.3±0.9	7.7±0.3	13.0±2.6	17.7±2.7
NH4NO3	15	6.2±0.27b,c	2.1±0.4b	37a	1.9	8.4±0.3a,b	0	0.3*	0.3	1.3	1.3	1.3
	150	47.0±4.0d	14.9±1.3d	0	0	62.1±5.2d	0	0	0	0	0	0
Glycine	15	9.3±1.5c	3.2±0.39b	35±28a	1.1±1.0	12.7±1.8b	0	0.3±0.3*	0.3±0.3	0.3±0.3	1.3±0.9	3.3±2.8
	150	60.9±6.5e	15.1±1.7d	0	0	76.1±8.2e	0	0	0	0	0	0
BSA	15	3.9±0.2a,b	1.7±0.2a,b	49±27a,b	2.8±1.7	5.8±0.4a,b	0	1±1*	1±1	8.0±1.5	13.7±2.3	23.3±2.3
	150	33.9±3.0f	9.6±0.2c	0	0	43.5±3.2c	0	0	0	0	0	0

Plants were grown without N for 3 months and grown for an additional 7 months with different N treatments. Low-N-treated plants commenced producing cluster roots 13 weeks after commencement of hydroponic culture with different N treatments, while plants grown in adequate N did not produce cluster roots. Phosphorus was omitted from the growth media after week 22. The average of three pooled seedlings in three pots ±SD is shown. Means marked with different letters are significantly different (P <0.05, ANOVA LSD post hoc test). The dry weight of plants was determined in week 26.

^*Cluster roots were produced by plants in one pot only.