Laser biostimulation of perennial ryegrass (<i>Lolium perenne L.</i>) seeds in a pilot study

In our pilot study, perennial ryegrass seeds were exposed to 0, 1, 2, 4, and 8 minutes of single-wavelength red laser (660 nm, 150 mW) irradiation, and were grown to 13 weeks of age. No statistically significant effects were observed in germination rate or seedling shoot length. However, the 2- and 4-minute treatments significantly increased shoot length in 13-week-old plants by 28% and 19%, respectively, compared to the control. There were no significant differences in shoot or root weight of the 13-week-old plants, though shoot dry weight was 57% to 65% higher across all treatments. The shoot-to-root dry weight ratio increased in all treatments compared to the control, with the 1-minute treatment significantly exceeding the control by 54%. The protein content of the entire seedlings was notably lower in the 1- and 2-minute treatments and higher in the 4-minute treatment than in the control, as measured by NIRS analysis. The fiber fractions examined (NDF, ADF, hemicellulose) surpassed the control values in the shoots of 13-week-old plants under all treatments, but these differences were not statistically significant.