Effect of sodium selenite supplementation on some pigments and biochemical parameters of Lactuca sativa L. growing hydroponically

Abstract

Selenium (Se) is a fundamental element that is beneficial to various organisms at tiny exposure levels and toxic at large concentrations. This research aims to study the effect of selenium as NaHSeO3 on water content, some photosynthetic pigments, carotenoids, proteins, and carbohydrate content in lettuce (Lactuca sativa L.). selenium used in the form NaHSeO3 in the concentrations of 0, 1, 5, 10, and 20 mg L-1 added to Hoagland solution and three growth periods (10, 20, and 30 days) was studied.  The application of Selenium (Se) led to a decrease in the percentage of water in lettuce leaves, recording the least decrease on the 30th day of the treatment at a concentration of 20  mg L-1, as well as the contents of total protein and carbohydrates in all concentrations compared to the control, except for the concentration 1 mg L-1, which recorded a non-significant increase in total protein and a significant increase in carbohydrates on the 30th day of treatment. Chlorophyll a decreased relatively, except for a concentration of 5 mg L-1, whose content increased on the 30th day of treatment, and the content of chlorophyll b, total chlorophyll and carotenoid increased in the selenium treatments compared to the control, recording the highest content of chlorophyll b and total chlorophyll in the concentration of 20 mg L-1 on the 20th day of the treatment, while the concentration of 5 mg L-1 recorded the highest content of carotenoid in all treatment periods.  The results of our study showed that low concentrations of selenium have a positive effect on the content of total protein and carbohydrates. however, the high concentrations harm them, while the concentration of 5 mg L and 20 mg L has a positive effect on the content of chlorophyll and carotenoids.