Cytochemical investigation of pollen and pollen tubes after γ-irradiation: effect of the irradiation on some dehydrogenases and hydrolases

A cytochemical investigation of the activities of six dehydrogenases and four hydrolases was carried out after irradiation of the pollen with 5-700 Kr gamma rays. Two-celled pollen of diploid Lilium regale and tri-celled pollen of both diploid and tetraploid Beta vulgaris were investigated. High doses of gamma irradiation inhibited pollen germination and pollen tube growth but did not affect or only slightly decreased the activity of glutamate dehydrogenase (GDH), isocytrate (IDH), malate dehydrogenase (MDH), glucose-6-phosphatea dehydrogenase (G6PDH), α-esterase and acid phosphatase. The radioresistance of the activity of these enzymes appears to be responsible for the high radioresistance of pollen. High doses of irradiation inhibited the lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH) activity which take part in the anaerobic breakdown of carbohydrates as well as the AS-D-esterase (pectin esterase) and β-gluosidase activity which are involved in the cell wall metabolism. It was concluded that the gamma irradiation inhibited the process of pollen tube elongation through inactivation of the enzymes AS-D-esterase and β-glucosidase which hydrolysed and softened the cell wall. The effects of high dose gamma irradiation were similar on both haploid and diploid pollen of both the taxa. (author). 37 refs