Bio-stimulatory effects of pulsed Nd:YAG laser irradiation of maize kernels on growth and yield: photosynthetic efficiency, chlorophyll fluorescence and water relations

Purpose Recently, the use of laser technology to enhance the growth and production of agronomic and horticultural crops as environmentally friendly way has gained considerable interest. However, very limited research has been conducted on the use of pulsed Nd:YAG laser irradiation of seeds, particularly regarding its effects on plants at later/adult growth stages.Materials and methods In present study different doses (0, 200, 400 and 600 J/cm2) were used as seed treatment of pulsed Nd:YAG laser to appraise their impacts on growth and yield potential of maize plants at the later vegetative stage, in relation to the modulations in different physiological attributes.Results Growth and seed yield of plants grown from seeds subjected to pulsed Nd:YAG laser found significantly better than plants grown from non-treated seeds. This improvement in growth and kernel yield resulting from laser seed irradiation was found positively correlated with improved performance in stomatal regulation due to better water relations, higher PS-II efficiency and increased levels of photosynthetic pigments. Greater improvements were recorded with irradiation with low fluence of 400 J/cm2 compared to the other laser doses. Moreover, the increase in biomass production was positively correlated with the studied physio-biochemical attributes.Conclusions In conclusion, the use of pulsed Nd:YAG laser as a pre-sowing seed irradiation treatment was found beneficial for enhancing the growth and yield of maize plants, even at the mature vegetative stage. The observed growth and yield improvements were found positively associated with enhanced stomatal regulation, improved water relations, higher photosynthetic efficiency, increased PSII efficiency, and elevated chlorophyll content, indicating a greater capacity for light absorption and more effective regulation of light-dependent reactions. Comparatively, seed irradiation at 400 J/cm2 of pulsed Nd:YAG laser resulted in greater improvements than the other tested fluence levels.