Enhanced emissions of floral volatiles by Diplotaxis erucoides (L.) in response to folivory and florivory by Pieris brassicae (L.)

Farré-Armengol G., Filella I., Llusia J., Primante C., Peñuelas J. (2015) Enhanced emissions of floral volatiles by Diplotaxis erucoides (L.) in response to folivory and florivory by Pieris brassicae (L.). Biochemical Systematics and Ecology. 63: 51-58.
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Doi: 10.1016/j.bse.2015.09.022

Resum:

The main function of floral emissions of volatile organic compounds (VOCs) in entomophilous plants is to attract pollinators. Floral blends, however, can also contain volatile compounds with defensive functions. These defensive volatiles are specifically emitted when plants are attacked by pathogens or herbivores. We characterized the changes in the floral emissions of Diplotaxis erucoides induced by folivory and florivory by Pieris brassicae. Plants were continually subjected to folivory, florivory and folivory + florivory treatments for two days. We measured floral emissions with proton transfer reaction/mass spectroscopy (PTR-MS) at different times during the application of the treatments. The emissions of methanol, ethyl acetate and another compound, likely 3-butenenitrile, increased significantly in response to florivory. Methanol and 3-butenenitrile increased 2.4- and 26-fold, respectively, in response to the florivory treatment. Methanol, 3-butenenitrile and ethyl acetate increased 3-, 100- and 9-fold, respectively, in response to the folivory + florivory treatment. Folivory alone had no detectable effect on floral emissions. All VOC emissions began immediately after attack, with no evidence of delayed induction in any of the treatments. Folivory and florivory had a synergistic effect when applied together, which strengthened the defensive response when the attack was extended to the entire plant. © 2015 Elsevier Ltd.

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Floral advertisement scent in a changing plant-pollinators market

Filella I., Primante C., Llusia J., Martin Gonzalez A.M., Seco R., Farre-Armengol G., Rodrigo A., Bosch J., Penuelas J. (2013) Floral advertisement scent in a changing plant-pollinators market. Scientific Reports. 3: 0-0.
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Doi: 10.1038/srep03434

Resum:

Plant-pollinator systems may be considered as biological markets in which pollinators choose between different flowers that advertise their nectar/pollen rewards. Although expected to play a major role in structuring plant-pollinator interactions, community-wide patterns of flower scent signals remain largely unexplored. Here we show for the first time that scent advertisement is higher in plant species that bloom early in the flowering period when pollinators are scarce relative to flowers than in species blooming later in the season when there is a surplus of pollinators relative to flowers. We also show that less abundant flowering species that may compete with dominant species for pollinator visitation early in the flowering period emit much higher proportions of the generalist attractant β-ocimene. Overall, we provide a first community-wide description of the key role of seasonal dynamics of plant-specific flower scent emissions, and reveal the coexistence of contrasting plant signaling strategies in a plant-pollinator market.

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