## 3 Results and Discussion
The best results (40 rows/ear) were obtained from the exposure time of 65 s at 4 mW/cm\({}^{2}\) with the green laser, followed by 85 s at 4 mW/cm\({}^{2}\) for the seed irradiated with the blue laser (39.1 rows/ear). The minimum number of rows per ears (20.5) was obtained with green laser at 85 s at 4 mW/cm\({}^{2}\). In the case of the leaf area, data in Table 2 showed significant differences when using various lasers and exposure times. A significant leaf size (517.5 and 510 cm\({}^{2}\)) was obtained by the blue laser for exposure time of 85 s and laser power at 2 and 4 mW/cm\({}^{2}\), respectively, whereas the leaf size for the unexposed control plant was recorded as 487.5 cm\({}^{2}\). The present study shows that most of the parameters (number or rows/ear, plant height, leaf area, seed yield, and yield efficiency) were significantly affected, except for weight of 300 seed and harvest index. Yet, low-radiation dose intensity activates the plants, resulting in an increase in the bio-energetic potential of the cells and greater activation of their biochemical and physiological processes, while high doses of irradiation influence the genetic material of cells, causing genetic changes in the plants [39]. A significantly larger leaf area was observed for the plants treated by the blue laser during the harvesting stage due to the increase in the photosynthesis activity, which, in turn, led to an increase in the leaf surface area of maize, as compared to the un-irradiated seeds (control). However, there was no significant effect on the leaf area for the seeds irradiated by various laser treatments. There was also an increase in the number of rows per ears as a result of an increase in the surface area of one leaf or an increase in the number of leaves per plant. In both cases, this led to an increase in the productivity of photosynthesis. Morphological changes in the plants grown from the seeds treated by He-Ne laser light of 50 mW were observed; they were taller and thicker than plants from seeds without irradiation (control), as reported by [PERSON] et al. [40]. Recently, some research studies were carried out on different light intensities and their effect on phases of plant growth [22, 41, 42]. Bio-stimulation using He-Ne laser and laser diodes was applied to improve the physiological quality of certain crops [16]. Hence, only a few studies were conducted on the influence of laser light on the formation of physiological indicators of plant productivity; this makes it difficult to compare the results obtained by  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Treatments**} & **No. of** & **Leaf Area** & **Plant Height** & **Weight of 300** & **Seed Yield** & **Harvest** & **Yield Efficiency** \\  & **Row (ear)** & **(cm\({}^{2}\))** & **(cm)** & **Seed (g)** & **(kg/ha)** & **Index (\%)** & **(g/cm\({}^{2}\))** \\ \hline \hline \multicolumn{8}{c}{Blue laser} \\ \hline L\({}_{3}\)T\({}_{1}\)S\({}_{1}\) & 30.5 \({}^{\text{\text{\tiny{$\textless{}$}}}}\) & 435.0 \({}^{\text{\tiny{$\textless{}$}}}\) & 198  
the present study with the results of other studies. The synergy of simultaneous events that happen when the seed is irradiated by laser light makes the mechanisms of bio-stimulation unclear [23]. Yet, tomato seeds (Solanum _Iycopersicum_ L.) were studied by applying a laser of 25 mW with exposure times of 5, 10, 20, 30, and 60 s [20]. It was found that the height of the plants showed a significant difference with respect to control (non-irradiated) samples. Our results were confirmed by [PERSON] and [PERSON] [43], whose study found that seeds pretreated with a laser (I = 5 mW/mm\({}^{2}\)) significantly increased the germination and growth parameters of four wheat varieties after seven days of treatment. [PERSON] et al. [44] applied treatment of low-intensity laser light at different irradiation doses on eggplant seeds (_Solanum melongena_ L.) and observed significant changes in later growth stage and yield; the best results were found radiation doses of 25 and 30 mJ/cm\({}^{2}\).