Changes in the Antioxidant System of Germinating Seeds and Sprouts of Pea with the Use of Micellar-Substrate Extract of Oyster Mushrooms

The reactions of the antioxidant system (AOS) of daily germinating seeds and 8-day-old pea seedlings cultivated using 10% and 100% aqueous extract from spent oyster mushroom straw substrate (hereinafter extract) were studied. The mother liquor was taken for 100% extract after its preparation, and the 10% was obtained by diluting the mother liquor. The plants were grown in oligotrophic hydroponic conditions and in eutrophic conditions on gray forest soil. The activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), expression of SOD-1, CAT-1, POD genes, and the content of low molecular weight antioxidants (NMAO): ascorbate, phylloquinones, and free proline were studied as the main indicators of the AOS reaction. The inhibitory effect of 10% and 100% extract on the activity of SOD and CAT, but not on the activity of POD in daily germinating seeds, has been shown. At the same time, the content of mRNA transcripts of the SOD-1 and POD genes decreased only slightly in seeds cultivated with 100% extract, in the remaining experimental groups the level of gene expression did not differ from the control. The content of ascorbate in all experimental groups did not differ from the control, and phylloquinones and free proline were less than in the control. In the leaves of 8-day-old seedlings cultivated in a hydroponic medium, in all experimental groups, the activity of AOS enzymes, the expression of their coding genes and the content of phylloquinones and free proline did not differ from the control. At the same time, the ascorbate content was higher. In plants cultivated in soil using a 10% extract, all EPA indicators did not differ from the control. In plants grown using 100% extract, the activity of SOD, the expression level of the SOD-1 gene, the content of ascorbate and free proline were higher, and the remaining indicators did not differ from the control. Thus, the extract at the initial stages of germination inhibited the AOS of peas, followed by restoration (in oligotrophic conditions) and enhancement (in eutrophic cultivation conditions) of its work.