Changes in ultrastructure and histochemistry of two red macroalgae strains of Kappaphycus alvarezii (Rhodophyta, Gigartinales), as a consequence of ultraviolet B radiation exposure.
Ultraviolet radiation (UVR) affects macroalgae in many important ways, including reduced growth rate, reduction of primary productivity and changes in cell biology and ultrastructure. Among red macroalgae, Kappaphycus alvarezii is of economic interest by its production of kappa carrageenan. Only a few reports have examined the changes in macroalgae ultrastructure and cell biology resulting from UVB radiation exposure. Therefore, we examined two strains of K. alvarezii (green and red) exposed to UVB for 3 h per day during 28 days and then processed them for histochemical and electron microscopy analysis. Reaction with Toluidine Blue showed an increase in the thickness of the cell wall and Periodic Acid-Schiff stain showed a decrease in the number of starch grains. UVBR also caused changes in the ultrastructure of cortical and subcortical cells, which included increased thickness of the cell wall and number of free ribosomes and plastoglobuli, reduced intracellular spaces, changes in the cell contour, and destruction of chloroplast internal organization. Based on these lines of evidence, it was evident by the ultrastructural changes observed that UVBR negatively affects intertidal macroalgae and, by extension, their economic viability.
Schmidt
Eder Carlos
EC
Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina 88049-900, CP 476, SC Florianópolis, SC, Brazil. edcash@terra.com.br
Scariot
Lidiane Angela
LA
Rover
Ticiane
T
Bouzon
Zenilda Laurita
ZL
D002473:Cell Wall / Q000648:ultrastructure; D003593:Cytoplasm / Q000737:chemistry; D006651:Histocytochemistry / Q000379:methods; D046529:Microscopy, Electron, Transmission; D015388:Organelles / Q000648:ultrastructure; D010503:Periodic Acid-Schiff Reaction; D000461:Rhodophyta / Q000737:chemistry / Q000528:radiation effects* / Q000648:ultrastructure; D013194:Staining and Labeling / Q000379:methods; D013213:Starch / Q000032:analysis; D014048:Tolonium Chloride / Q000378:metabolism; D014466:Ultraviolet Rays
D014048:Tolonium Chloride; D013213:Starch