## 3 Results and Discussion
### Elements Concentrations in Leaves of Pumpkin
The value of photosynthesis intensity for the low PAR was, respectively, 0.713 and 0.646. Light intensity in all study samples was reduced at the SII and increased at the stage of SIV when compared to the control. Photosynthetic efficiency at the onset of SII was increased in all study groups compared to the control. The highest increase was observed in the group treated with AgNC and reached 29%. Low intensity of PAR means that a large dose of energy was absorbed, which had a positive effect on photosynthesis, which, in plants soaked in silver, reached 0.728. Low PAR intensity resulted in increased photosynthetic activity at SII while reducing the same at the SIV. The described studies indicated an increase in terms of photochemical efficiency and greenness index at the SII in all study groups when compared to the control. The highest values of photochemical efficiency and greenness index were observed in leaves grown from seeds soaked in AgNC. The same were respectively 26 and 11% higher than in the control. According to a study by [PERSON] et al. (2018) on safflower plants (_Carthamus tinctorius_ L.) treated with laser beams (wavelength 632.8 nm) at different times (0.5 h, 1 h, 1.5 h) showed a differentiation in photosynthetic activity, but its increase was noticed compared to the control. In our research, laser light had a variable effect on the photosynthesis efficiency in pumpkin leaves depending on the stage of development. It was the highest in the SII (14%) and SIII (4%) phases. In other studies on long-term laser beam irradiation (wavelength 632.8 nm), it was noticed that the photosynthetic activity did not differ significantly between the research objects ([PERSON] et al., 2018). According to research study by [PERSON] et al. (2018) regarding the effect of red (R), white (B) and mixed light (RB) on the photosynthesis efficiency in red pepper leaves, it was noticed that the leaves were thicker and the ability to transpose electrons in the process of photosynthesis and its speed increased by lights B and RB. Figure 5: Mean content of chlorophyll \(a+b\) and carotenoids (from seed leaves grown in pots for 14 days) in the respective study groups. C—control; L—laser light; \(p\)—magnetic field; AgNC—silver nanocolloid. Different letters a\(\rightarrow\)b—significant differences (\(p\leq 0.05\)), the same letters—no difference between the control. The mean value of Y(II) was within the range from 0.644 (SII) to 0.685 (SIII) and the ETR value from 24.11 (SIII) to 51.37 (SI) (Figure 6). In the present study, the application of silver nanocolloid produced an improvement in terms of photochemical efficiency, particularly at the stages of: budding and onset of flowering. Based on the data presented in Table 5, no significant correlation between the Y(II) and ETR at the respective stages can be identified. Average correlation (significance at the level of \(\alpha\) = 0.05) could only be observed between the SII and SIII (r = 0.408) and between the SII and SIV (r = 0.465). To recapitulate the presented study, it can be observed that the use of various techniques intended as a way to improve germination as well as photosynthetic pigment content and photosynthetic efficiency, yielded varying results. The greenness index at the stages of: budding, onset of flowering, and flowering was higher in all plants grown from seeds treated with laser light and alternating magnetic fields as well as soaked in silver nanocolloid, when compared to the control. On the other hand, the same was lower at the stage of fructification due to the aging of leaves and their change to a more yellowish-orange color.