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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Effects of UV-B radiation on growth rates, pigment content and ultrastructure of red (wild type), greenish-brown and green strains of Gracilaria birdiae (Gracilariales, Rhodophyta)

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Ayres-Ostrock, Ligia M. [1] ; Plastino, Estela M. [1]
Total Authors: 2
[1] Univ Sao Paulo, Inst Biociencias, BR-05508090 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: European Journal of Phycology; v. 49, n. 2, p. 197-212, 2014.
Web of Science Citations: 2

Based on physiological characteristics, we hypothesized that different strains of Gracilaria birdiae from two distinct geographical areas of the Brazilian coast (2500 km apart) would have different responses to long-term exposure to UV-B radiation (UV-B). The locations differ in their environmental conditions: one is a warmer area, Ceara State (CE), closer to the equator; the other is a colder area, Espirito Santo State (ES), closer to the Tropic of Capricorn. To test the hypothesis that the CE population is more resistant to UV-B than the ES population, apical segments of the red (RDCE, RDES), green (GR(CE)) and greenish-brown (GB(CE)) strains were cultivated in the laboratory under two treatments: control (PAR) and artificial UV-B (PAR + UV-B). Algal performance was evaluated by considering growth rates, pigment content and ultrastructural analysis. Compared with the control, all strains showed a decrease in growth rates after exposure to UV-B. Of all strains, RDES showed the greatest sensitivity to UV-B. However, a decrease in growth rate and morphological changes were observed to a lesser extent in the RDCE strain. Moreover, exposure to UV-B resulted in a decrease in the concentrations of phycobiliproteins in the RDCE strain. The GB(CE) strain showed an increase in phycoerythrin (PE)/allophycocyanin (APC) and phycocyanin (PC)/allophycocyanin (APC) ratios after exposure to UV-B, suggesting this strain had a higher tolerance to the radiation. No differences in the chlorophyll a and carotenoid content were found between the control and UV-B treated samples for all strains. Ultrastructural changes, such as damage to chloroplasts and mitochondria, were present in all strains after exposure to UV-B. In summary, our findings support the hypothesis that the population from Ceara State has adapted to the higher irradiation and is thus more resistant to increased UV-B. Additionally, of the strains tested, the GB(CE) and RDCE strains appear to be more resistant to this radiation. (AU)

FAPESP's process: 10/50175-3 - Intraspecific diversity of the gracilarioid algae (Gracilariales, Rhodophyta)
Grantee:Estela Maria Plastino
Support type: BIOTA-FAPESP Program - Regular Research Grants
FAPESP's process: 11/10189-8 - Population studies in Gracilaria birdiae (Gracilariales, Rhodophyta): molecular and physiological aspects
Grantee:Lígia Maria Ayres Ostrock
Support type: Scholarships in Brazil - Doctorate