Infrared laser radiation (l=980nm) application for photobiostimulation of wheat seeds (Triticum aestivum L)

Recently has appeared a considerable quantity of publications connected with the application of microwaves and laser radiation for stimulation of different types of biological systems, particularly of plants seeds to improve their vigor, the germination and the yield [1-8]. In the most of these publications He-Ne lasers with λ=632.8 nm were applied to improve the parameters mentioned above in the plants seeds [3-8]. Yi-Ping Chen et. al. [8] radiated the seeds embryos of Isatis indigotica Fort with an He-Ne laser (λ=632.8 nm) with an intensity of 5.23 mW/mm² and an exposition time to laser radiation of 5 min and with a microwave source with an intensity of 1.26 mW/mm² and an exposition time to microwave radiation of 8s. The results reported in the previous work [8] indicate that the He-Ne laser radiation and the microwave radiation enhanced the activity of the enzymes of the cotyledon that leads to an increase of the velocity of its growth. Wilczek et al [4] reported the use of He-Ne laser with a wavelength of λ=632.8 nm to accelerate the germination of alfalfa seeds. The intensities of laser radiation used in the above research were 3 mW/cm ² and 6 mW/cm². The exposition times to laser radiation were 0.1s, 0.3s and 0.5s. The results obtained in the previous work reported decreases on the percentage of seeds germinated abnormally and on the percentage of non-germinated seeds.