Table 3. Correlation coefficients (r) among total phenolic acids contents of rice root-exudates, rice allelopathic potential andfine- root traits of three rice cultivars.

		Plant		Root morphological trait
		RAP	PAC	RL(1)	RL(2)	RTN	RSA	RV
Plant	RAP	/
	PAC	0.914***	/
Root morphological trait	RL(1)	0.906***	0.958***	/
	RL(2)	0.428	0.477	0.568	/
	RTN	0.921***	0.937***	0.972***	0.437	/
	RSA	0.451	0.406	0.599	0.991***	0.447	/
	RV	0.249	0.407	0.496	0.953***	0.429	0.962***	/
Root proliferative trait	RB	0.843**	0.895**	0.946***	0.825**	0.928***	0.848**	0.698*

Notes.

RAP- rice allelopathic potential(% inhibition on plant dry weight of lettuce), PAC- total phenolic acids contents of rice root-exudates, RL(1)- root length at 0-0.2mm, RTN- root tips number, RL(2)- root length at 0.2–2.0 mm, RSA- root surface area, RV- root volume, RB- root biomass.

^*0.01 <  P < 0.05.

^**0.001 <  P < 0.01.

^***P < 0.001.