Thermal Changes of Maize Seed by Laser Irradiation

In this research, the thermal evolution in maize seeds (Zea mays L.) was studied when low-intensity laser irradiation was applied during 60 s. The seeds were irradiated in three different conditions: suspended in air, placed on an aluminum surface, and finally placed on a cardboard; the evolution of the seed temperature was measured by an infrared camera. Photoacoustic spectroscopy and the Rosencwaig and Gersho model were used to determine the optical absorption coefficient ($$\beta $$β) of the seeds. The results indicate that using 650 nm laser light and 27.4 mW, it is possible to produce temperature changes (up to $$9.06~^{\circ }\hbox {C}$$9.06∘C after 1 min) on the seeds. Comparing the mean temperature of the seeds, during and after the incidence of light from a laser, it was found that there were statistically significant differences ($$P\le 0.05$$P≤0.05) from time $$t_{1}$$t1 to time $$t_{16}$$t16 ($$t_{1}$$t1 to $$t_{16}$$t16) and $$t_{3}$$t3 to $$t_{16}$$t16, for the laser turned on and off, respectively. The seed condition that had the highest temperature variation, relative to the initial temperature (during the irradiation laser exposure), involved the seeds suspended in air. With regard to the stage of decay of the temperature, it was found that the seed condition that decays more slowly was the seed placed on the cardboard. It was also found that black-dyed maize seeds are optically opaque in the 300 nm to 700 nm range Also, the thermal diffusion length is smaller than the optical penetration length. In the present investigation, it was shown that there is a thermal component associated with the mechanisms of laser biostimulation, which is also a function of the container materials of the seed. In this way, the effects of laser treatment on maize seeds involve at least a temperature effect. It is important to know the temperature changes in the seeds that have been irradiated with a laser beam since they could have substantial practical and theoretical importance.