Studies On The Effect Of Laser Radiation And Other Mutagens On Plants

Abstract

newlineThe effect of lasers of three wavelengths in the visible region - 476, 488 and newline514 nm on mitotic and meiotic cell divisions, growth, yield and activity of newlinespecific enzymes were studied in two taxonomically diverse plant species newlineA/lium cepa L. and Vicia faba. The effect of laser exposures was compared with newlinethe effect of two physical mutagens (Gamma and Ultraviolet radiations) and two newlinechemical mutagens (Ethyl Methane Sulphonate and Hydroxyl amine). The study newlineindicated that lasers could be mutagenic causing aberration in the mitotic and newlinemeiotic cell divisions while also producing changes in the growth and yield of newlinethe plants. Lasers of higher wavelengths 488 and 514 nm caused aberrations in newlinethe early stages of mitotic cell division whereas lasers of lower wavelengths newline(476 nm) caused more aberrations in the later stages of mitotic cell division. newlineLaser exposure of 488 nm wavelength at power density 400 mW induced higher newlinemitotic and meiotic aberrations and also induced higher pollen sterility than newlinelasers of 476 and 514 nm. The frequency of mitotic aberrations induced by newlinelasers was lesser than that caused by y-irradiation but comparable to that newlineinduced by EMS and HA. Lasers cause mutations in higher frequencies than UV. newlineLasers had a stimulatory effect on growth and yield in both plant species. This newlinestimulatory effect of lasers on germination could not however be correlated to newlinethe activity of amylase and protease, the key enzymes in seed gennination. newlineEnzymes such as peroxidase and catalase, involved in scavenging of free newlineoxygen radicals often produced by irradiation, did not show increased activity in newlinelaser irradiated samples. Further studies are required for elucidating the exact newlinemechanisms by which lasers cause mutations.