## 3 Results and Discussion
### Biometric Parameters of Seedlings
This parameter was highest (5.1 g) in cauliflowers grown on PRO3 and white cabbage grown on the control substrate, and it was lowest (1.8 g) in broccoli grown on PRO1. Substrate PRO1 exerted a negative impact on the mass of cauliflower leaves which were around 36% lighter than the leaves of control cauliflower seedlings. An even greater difference was observed in the mass of broccoli leaves which was around 44% lower on PRO1 than on the control substrate. The substrates used in the experiment did not induce a significant decrease in the mass of cabbage leaves. Root mass also differed in _Brassica_ plants grown on various substrates, but the observed differences were species-specific. Root mass ranged from around 38 g in cauliflowers grown on PRO3 to around 58 g in broccoli grown on the control substrate. In comparison with control plants, root mass was higher in white cabbage grown on PRO1 (by approx. 9%) and PRO3 (by approx. 2%), and in cauliflowers grown on PRO1 (by approx. 8%). Broccoli seedlings grown on all three substrates used in the experiment were characterized by a lower root mass (approx. 23% on PRO1; approx. 7% on PRO2; approx. 22% on PRO3) than control plants (Figure 3). Substrate PRO2 had the most stimulatory effect on root development, compared with the control substrate (Figure 3). The stimulatory effects of the remaining used in the experiment substrates differed across species, but the substrates used in the experiment and the control substrate promoted root development in _Brassica_ plants to a similar extent. Broccoli seedlings were characterized by the most extensive root system when grown on PRO2 and PRO3, and broccoli roots were only somewhat less well developed on PRO1. Cauliflowers produced the strongest roots on PRO2, and cauliflower root systems were also well developed in PRO3 and control treatments. In cabbages, the root system was better developed in all substrates (PRO1, PRO2, PRO3) than in the control substrate. Similar values of biometric properties were reported by [PERSON] [29] and [PERSON] et al. [30]. The physical and chemical parameters of soil and substrate are robust indicators of their quality, and they significantly affect root growth and development [31]. Plant roots thrive in substrates characterized by adequate infiltration, drainage, water-holding capacity, porosity and density, and a high content of macronutrients and micronutrients. Root growth and development can be enhanced through agricultural practices that improve the physical and chemical properties of substrates [32; 33; 34; 35]. According to [PERSON] et al. [36] and [PERSON] et al. [31], a functional relationship exists between roots and shoots in most plant species, and root growth probably contributes to a higher shoot biomass. In the work of [PERSON] [2], the tested substrates and growth media significantly affected the growth (leaf fresh weight and leaf morphology) and physiological parameters (stomatal conductance, leaf temperature, and chlorophyll content) of lettuce and nap cabbage seedlings. Seedling quality affects plant  
Figure 3: Leaves and roots of _Brassica_ vegetables grown on different substrates: (**a**) broccoli, (**b**) cauliflower, (**c**) white cabbage; 0—control substrate, I—PRO1, II—PRO2, III—PRO3. growth and yields after transplanting. High-quality seedlings should be characterized by thick stems, thick, dark green leaves, and large white roots. Plant biomass and leaf number were increased at 2.5% SCG for broccoli and cabbage but maintained at cauliflower when compared with control. The SCG at 10% decreased the stomatal conductance of broccoli and cabbage (including 2.5-5.0% SCG in cauliflower) while chlorophyll content was increased at 10% of SCG media [36].