Effect of gamma and UV-B/C radiation on plant cells.

The biological effect of gamma-rays is based on the interaction with atoms or molecules in the cell, particularly water, to produce free radicals, which can damage different important compounds of plant cell. The UV-B/C photons have enough energy to destroy chemical bounds, causing a photochemical reaction. The biological effect is due to these processes. This paper is focused on the structural and biochemical changes of the cell wall and plastids after gamma and/or UV-B irradiation. Gamma-rays accelerate the softening of fruits, causing the breakdown of middle lamella in cell wall. They also influence the plastid development and function, such as starch-sugar interconversion. The penetration of UV-B light into the cell is limited, while gamma-rays penetrate through the cells. For this reason, UV-B light has a strong effect on surface or near-to-surface area in plant cells. UV-B radiation influences plastid structure (mostly thylakoid membranes) and photosynthesis. Some kinds of pigments, such as carotenoids, flavonoids save plant cells against UV-B and gamma irradiation. Plant cells are generally ozone sensitive. The detoxifying systems operate at the cellular level. Methods for studying structural changes in plant cells develop in direction to molecular biology, combined with immunoassays and new microscopical techniques. Nowadays, UV-B radiation is undergoing much research, being an environmental factor which causes damage to both humans and plant cells.