Journal Article

Dynamics of violaxanthin and lutein epoxide xanthophyll cycles in Lauraceae tree species under field conditions

Raquel Esteban, Eduardo T. Jiménez, M. Soledad Jiménez, Domingo Morales, Koldobika Hormaetxe, José María Becerril and José Ignacio García-Plazaola

in Tree Physiology

Volume 27, issue 10, pages 1407-1414
Published in print October 2007 | ISSN: 0829-318X
Published online October 2007 | e-ISSN: 1758-4469 | DOI: http://dx.doi.org/10.1093/treephys/27.10.1407
Dynamics of violaxanthin and lutein epoxide xanthophyll cycles in Lauraceae tree species under field conditions

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Two xanthophyll cycles have been described in higher plants: the violaxanthin xanthophyll (V or VAZ) cycle, which is present in all species, and the taxonomically restricted lutein epoxide xanthophyll (Lx) cycle, which involves the light-induced de-epoxidation of Lx to lutein (L) and its epoxidation back to Lx in low light. Laboratory experiments indicate that the first reaction occurs quickly, but the second reaction is much slower. We investigated the Lx cycle under field conditions in several tree species of the Lauraceae family to determine its relationship with the ubiquitous V cycle. The field study was conducted in two natural laurel forests: one in the Canary Islands, where Laurus azorica (Seub.) Franco, Ocotea foetens (Aiton.) Benth, Apollonias barbujana (Cav.) Bornm. and Persea indica (L.) Spreng were studied; and one in the Basque Atlantic coast where Laurus nobilis L. was studied. The results were complemented by a taxonomic study. The presence of Lx was widespread among Lauraceae species, but its concentration varied even among closely related species. The V pool size correlated positively with growth irradiance, whereas the relationship between Lx pool size and growth irradiance varied with species. A functional Lx cycle was confirmed under field conditions only in O. foetens and L. nobilis. Furthermore, in O. foetens, a correlation between Lx de-epoxidation and photoinhibition suggested a protective role for this cycle. We conclude that, unlike the V cycle, which is normally correlated with irradiance, the operation and light dependence of the Lx cycle is species-dependent.

Keywords: de-epoxidation; laurel forest; Laurus; Ocotea; photoinhibition; photoprotection

Journal Article.  0 words. 

Subjects: Plant Sciences and Forestry

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