Effects of Individual and Simultaneous Selenium and Iodine Biofortification of Baby-Leaf Lettuce Plants Grown in Two Different Hydroponic Systems

Abstract

The iodine (I) and selenium (Se) deficiencies affect approximately 30% and 15%, respectively, of the global population. The biofortification of vegetables is a valid way to increase the intake of iodine and selenium through the diet. This study was carried out on baby-leaf lettuce to investigate the effects on plant growth, leaf quality, and leaf I and Se accumulation of adding potassium iodide and sodium selenate, separately and simultaneously, to the nutrient solution in a floating system and aeroponics. The effect of I and Se biofortification on post-harvest quality of lettuce leaves was also evaluated. Our results evidenced that the Se and I treatments increased the content of the two microelements in lettuce leaves without any negative interactions in the plants, when applied either separately or simultaneously. Both hydroponic systems proved to be suitable for producing Se and/or I enriched lettuce. Biofortification with Se was more effective when performed in aeroponics, whereas I biofortification was more effective in the floating system. Quality of leaves during post-harvest storage was not affected by neither of the treatments. Lettuce leaves enriched with 13 µM Se and 5 µMI could be good dietary sources of Se and I without inducing toxic effects in humans.

Iodine biofortification of Swiss chard (Beta vulgaris ssp. vulgaris var. cicla) and its wild ancestor sea beet (Beta vulgaris ssp. maritima) grown hydroponically as baby leaves: effects on leaf production and quality

“…These concentrations were chosen based on the results of previous experiments on lettuce and basil grown in floating raft systems. 10,11 In these experiments, the iodine concentrations mentioned above allowed a satisfactory plant biofortification with no reduction of crop yield.…”

“…Iodine was added to the nutrient solution, 3 days after transplanting, as KI at a concentration of 0 (control), 0.5, 1.0, and 1.5 mg L −1 . These concentrations were chosen based on the results of previous experiments on lettuce and basil grown in floating raft systems 10,11 . In these experiments, the iodine concentrations mentioned above allowed a satisfactory plant biofortification with no reduction of crop yield.…”

“…7 Plants absorb iodine, as organic-iodine, iodate and iodide, from the soil through the root system and from the atmosphere, as gaseous iodine molecules, through the leaves. 6 Several studies have been conducted on iodine biofortification of hydroponically grown plants, 8 for example spinach, 9 basil, [10][11][12] and lettuce 13 with contrasting effects on leaf quality. For example, biofortification with iodine may increase, 14 reduce, 15 or not affect 10 the leaf nitrate content.…”

Factors Affecting Production, Nutrient Translocation Mechanisms, and LED Emitted Light in Growth of Microgreen Plants in Soilless Culture

“…Supplying 2 and 15 ppm of iron improved iron concentration and morphological characteristics such as larger leaves and longer hypocotyl, and doses of 15 ppm, 2 ppm, and 5 ppm of iron fortified chlorophyll content, flavonoid content, nitrogen balance, and plant senescence in broccoli in a closed system through the nutrient solution method . The distribution of 4 mg/L and 8 mg/L selenium fortified micronutrients and antioxidant compounds and improved defense response in basil in a closed system through the nutrient solution method . Doses of 1.50 mg/L and 3 mg/L iron chelate improved iron content in the leaves of purple kohlrabi, radish, pea, and spinach and improved iron content in the shoot of purple kohlrabi, radish, pea, and spinach in a growth chamber through the nutrient solution method …”

“…217 The distribution of 4 mg/L and 8 mg/L selenium fortified micronutrients and antioxidant compounds and improved defense response in basil in a closed system through the nutrient solution method. 218 Doses of 1.50 mg/L and 3 mg/L iron chelate improved iron content in the leaves of purple kohlrabi, radish, pea, and spinach and improved iron content in the shoot of purple kohlrabi, radish, pea, and spinach in a growth chamber through the nutrient solution method. 219 Supplying 135 mg/L and 405 mg/L selenium improved organic and inorganic selenium and phenolic acid content in sprouts, and supplying the optimum amount of 15 mg/L and 45 mg/L selenium improved selenium content, phenolic acid content, and yield in rice in a closed system through the nutrient solution method.…”