The role of cell selection for pollen grain fertility after treatment of barley sprouts (Hordeum distichum L.) with UV-B irradiation

UV-B irradiation of barley sprouts within the range of 0.5-4.3 kJ/m2 induced an increase in the number of chromosome aberrations in the root meristem and pathologies in the reproductive system. Enhancement of cytomixis, increase of polymorphism and cytopathology of pollen grains were observed in the male generative system. The inverse trend was observed when intensity of cytomixis was compared to the pollen grain sterility. Damages induced by low doses of UV-B radiation were eliminated neither by DNA reparation nor by cell selection and were preserved in many cell generations. High UV-B level led to the activation of cytomixis due to which the population of microsporocytes was released from the excess load. It is presumed that cytomixis present a form of cell selection which was induced by an excess of microsporocyte disturbances.