Modification of soybean and lupine sprouting conditions: influence on yield, ROS generation, and antioxidative systems

Formation of free radicals’ and antioxidants’ biosynthesis during seeds sprouting strongly depends on plant growth conditions, especially while sprouts are fortified in iron. The influence of watering with FeSO4 solution on soybean and lupine sprouting, yield of iron accumulated in plant tissue, as well as free radical (reactive oxygen and nitrogen species) synthesis and antioxidant activity (capacity) were the objective of this study. Optimal iron accumulation and biomass efficiency were obtained for 3 day watering with water, followed by abiotic stress application (Fe2+ ions). For lupine sprouts, maximal radical formation (up to ~ 5.7 a.u.) took place on the fifth day of culturing in these conditions, while, for soybean sprouts, continuous increase in their activity was observed until the seventh day (up to ~ 5.8 a.u.). Total antioxidant activity in lupine sprouts increased definitely, even more than three times during 7 days of lupine growing, but, for soybean, it was almost steady. The same trend was observed in phenolic compounds and flavonoids contents. For soybean sprouts, these antioxidants were almost steady, while, for lupine sprouts in these conditions, the intensive synthesis of these antioxidants was observed. In response to high iron content applied from the fourth day in the cultivation media, lupine sprouts synthesize low molecular antioxidants effectively. For soybean sprouts, another mechanism of defense against oxidative stress should be expected.