IMPACT OF CO2 ON QUALITY OF BABY LETTUCE GROWN UNDER OPTIMIZED LIGHT SPECTRUM

The cost and yield are two the most important criteria in agriculture by which optimization of environmental factors are needed to carry out. In the present study, we investigated the efficient lighting spectrum and elevated CO2 concentration for cultivating healthier plants more rapidly. One of the aims of our study is to optimize LEDs light spectrum for healthier vegetable production in greenhouses and maximum economical benefits for growers. The impact of elevated carbon dioxide (CO2) concentration on antioxidant and nutritional properties of green leaf 'Multigreen 3' and red leaf 'Multired 4' baby leaf lettuce (Lactuca sativa L.), grown under optimized light spectrum was investigated. CO2 concentrations of 0.963 g . dm(-3) and 1.938 g . dm(-3) were maintained in the growth chambers. Lettuce was grown under four wavelength (640, 455, 660 and 735 nm) light-emitting diode based (LED) illumination. Under 0.963 g . dm(-3) CO2 conditions, 'Multired 4' lettuce represented higher antioxidant value due to higher ascorbic acid, anthocyanin, tocopherol contents and higher sucrose concentration, as compared to 'Multigreen 3' lettuce. Higher CO2 concentration (1.938 g . dm(-3)) had uneven effect on the quality of both baby leaf lettuce cultivars. Red leaf lettuce reacted to the higher CO2 level by lowered a tocopherol, ascorbic acid concentrations and significantly higher glucose contents in their leaves, when green leaf lettuce contrarily contained higher ascorbic acid and a tocopherol concentrations under 1.938 g . dm(-3) of CO2.