Effect of light quality (LQ) and lighting method (LM) on the levels of beta-carotene (beta-car) and anthocyanin (antho) in green romaine lettuce.

Least-square means with standard error of the model (in parenthesis) are shown in the table. Statistical significance of main and interaction effects of the fitted model is shown below the table. The symbols ‘*’, ‘**’, and ‘***’ indicate P values ≤ 0.05, 0.005, and 0.0005 respectively, and ‘n.s.’ indicate no statistical significance. The least-square means with a different letter are statistically different (Tukey-Kramer procedure).