Impact of Silicon on Chemical Properties of Drainage Water from Lettuce Following Determination of Proper Cultivar and Light Spectrum

ABSTRACT

Silicon (Si) is the second most abundant element on the earth’s crust. Growth and defense responses of plants can be influenced by Si availability. To evaluate the effect of Si on lettuce growth and properties of its drainage water, two experiments were conducted. The first experiment was conducted in a factorial template with four different cultivars (”Romana,” “Angelֹ,” “Monocasa,” and “Primavera”) and three different light spectra including white, yellow, and white-red. Statistical analysis showed that cultivar and spectrum had a significant effect (P ≤ 0.01) on lettuce growth. Romana cultivar under white light with the highest fresh weight and lowest water use had the best performance among the treatments. The highest water use efficiency (WUE) was detected in Romana cultivar under white spectrum. The second experiment was performed using six different levels of Si (0, 1, 2, 3, 4, and 5 g/pot) on Romana cultivar under white spectrum (best treatments obtained from the first experiment) with seven replications. Si had positive effects on vegetative growth of lettuce plants. The highest biomass was obtained by application of 3 g/pot Si. Si significantly influenced all of the chemical characteristics of drainage water. Increase in pH was detected by an increase in the concentration of Si. By increasing Si concentration, EC and NO³⁻ levels were increased and K⁺ was decreased in the drainage water. In conclusion, it is observed that application of Si under white spectrum for Romana cultivar improves WUE and lettuce growth. Its application also influences the chemical properties of drainage water.

KEYWORDS:

• Silicon
• light spectrum
• drainage water
• lettuce