title: UV-B effect on constituents of Azolla caroliniana.
abstract: Changes in growth and ultrastructure of Azolla caroliniana in response to elevated UV-B radiation were investigated. Exposure of plants to UV-B radiation for 1, 8, 16, 24 and 48 h exhibited a significant decrease in biomass and relative growth rate. This decrease resulted in an increase in doubling time over the control. Also, Chl a and b contents were significantly decreased especially after 16 h. The reduction was accompanied by a decrease in 5-aminolaevulinic acid content (precursor of chlorophyll). On the other hand, contents of carotenoid and UV-absorbing phenolic compounds (flavonoids and anthocyanins) were increased.
authors.affiliation: Botany Department, Faculty of Science, Alexandria University, 21511 Alexandria, Egypt.
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Ibrahim
authors.forename: Eazaz M
authors.initials: EM
authors.lastname: Mostafa
mesh_terms: D000064:Acclimatization; D018533:Biomass; D002455:Cell Division / Q000187:drug effects; D002473:Cell Wall / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism / Q000528:radiation effects; D002736:Chloroplasts / Q000528:radiation effects; D007700:Kinetics; D032498:Pteridium / Q000166:cytology / Q000254:growth & development / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D002734:Chlorophyll