The role of non‐glandular emergences in Croton floribundus (Euphorbiaceae) upon elevated ozone exposures |
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Authors: | Mrcia Gonalves Dias Brbara Baêsso Moura Giselle da Silva Pedrosa Silvia Ribeiro de Souza Poliana Cardoso‐Gustavson |
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Institution: | Márcia Gonçalves Dias,Bárbara Baêsso Moura,Giselle da Silva Pedrosa,Silvia Ribeiro de Souza,Poliana Cardoso‐Gustavson |
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Abstract: | A role of non‐glandular emergences in avoiding ozone (O3) damages by preventing its entrance into leaf tissues has been suggested in the O3‐tolerant species Croton floribundus (Euphorbiaceae). However, this function against O3 damage has been underestimated due to the covering wax layer, mostly composed of saturated hydrocarbon, which has low O3 reactivity. To evaluate the role of these emergences in conferring tolerance to O3, we mechanically removed the non‐glandular emergences from leaf blades of C. floribundus, submitted the plants to acute O3 fumigation, and assessed morphological and microscopic alterations. Plants with intact leaves treated with O3 showed the same phenotype as control samples but showed microscopic indicators of accelerated senescence. These alterations indicated a whole‐plant response to O3. In contrast, plants whose leaves had got their emergences removed exhibited specific morphological symptoms as well as microscopic O3 damage. We thus conclude that the leaf emergences constitute a barrier for volatile contention, preventing O3 damage to leaf tissues in C. floribundus. When these structures have been removed, defense volatiles are possibly quickly dispersed, makes this species vulnerable to O3. This study highlights the relevance of surface structures for plant resistance to O3 damages, complementing biochemical defenses. |
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Keywords: | accelerated leaf senescence mechanic removal of non-glandular emergences ozone fumigation polyphenols accumulation |
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