The influence of a natural source of magnesium – the mineral brucite on the physiological and biochemical parameters of leaf lettuce under hydroponic conditions

The effect of leaf fertilizing by a stabilized aqueous suspension obtained from finely dispersed brucite powder (magnesium hydroxide of natural origin) in comparison with the effect of a solution of magnesium sulfate 7-aqueous (MgSO4?7H2O) on the physiological, biochemical and morphometric parameters of plants of lettuce of the “Success” variety cultivated on the media with different Mg content under hydroponic conditions (full medium – 100% of Mg; incomplete medium – 40% of Mg). It was found that the suspension drug had the best effect when growing plants in an environment with magnesium deficiency, which was expressed in an increase in of leaf length. The dry weight of the leaf increased at the same time on a full medium with the action of 2 drugs in the same way. Treatment with Mg-containing preparations led to stabilization of the content of chlorophylls a and b and carotenoids. In this case, the effect was most pronounced when MgSO4 was used. Using atomic absorption spectroscopy, it was shown that in plants on an incomplete medium, 1 day after treatment with Mg-containing preparations, the magnesium content increased 3.4 times compared with the control. Then, on an incomplete medium, the Mg content in the leaves stabilized by 14 days and approached the level of control treatments. In the full medium, the Mg content decreased by 2 times during MgSO4 treatment and remained at the level of control variants treatments under the action of brucite suspension. As a result, it was shown that the suspension of the mineral brucite and MgSO4 studied by us had a positive effect on both the physiological and morphological (length and dry weight of the leaf) and biochemical parameters (content of Mg and photosynthetic pigments) of lettuce leaves. The best result was obtained in the case of plant growth in an environment with magnesium deficiency.