Physiological differences of 'Crocantela' lettuce cultivated in conventional and hydroponic systems

Conventional soil and hydroponic growing systems have inherent differences in water and nutritional availability. These differences may affect plant physiological development and biochemistry. The objective of this study was to evaluate lettuce (Lactica sativa) cv. 'Crocantela' development in either a hydroponic system or in soil through analyses of vegetative growth; chlorophyll abundance; and sugar and starch content. We evaluated the dry mass (DM), fresh mass (FM), number of leaves (LN), stomatal density and contents of chlorophyll, carotenoids, sugars and starch. Due to the improved nutritional conditions, especially in relation to macronutrients, plants grown in hydroponic system presented significant differences in chlorophyll a (0.4481 mg/g), b (0.1233 mg/g) and total chlorophyll content (0.5714 mg/g), as well as greater biomass when compared to plants cultivated in pots (FM: 342.69 g; DM: 21.13 g; NL: 17.75 g). The lower water availability for plants cultivated in pots influenced the increase in carbohydrate concentration and stomatal density in leaves (adaxial: 45.83 stomates/mm(2); abaxial: 64.75 stomates/mm(2)) of lettuce plants.