Table 3.

The effect of different light qualities and three replacement methods of nutrient solution on physiological characteristics of two varieties of lettuce in floating hydroponics.

Source of Variation	Df	Proline	Soluble sugar	Soluble protein	Phenolic compounds
Variety (V)	1	0.044*	3.04**	0.21ns	0.0001ns
Light (L)	3	0.55**	12.6**	0.95**	10.9**
Nutrient solution (N)	2	0.05**	0.07ns	0.02ns	1.20**
V*L	3	0.26**	13.4**	0.76**	4.33**
V*N	2	0.36**	16.3**	1.29**	12.24**
L*N	6	0.54**	7.49**	0.56**	8.25**
V*L*N	6	0.22**	4.51**	0.25*	4.48**
Experimental Error	48	0.008	0.52	0.09	0.019
Coefficient Variance (%)	–	4.3	4.04	6.62	1.62

^ns, * and ** indicate non-significance, significant at 5% and 1% probability level (Duncan’s Test), respectively.