The complexity of factors driving volatile organic compound emissions by plants.

Peñuelas J, Llusià J (2001) The complexity of factors driving volatile organic compound emissions by plants. Biologia Plantarum 44:481-487.

Emission of volatile organic compounds by apple trees under spider mite attack and attraction of predatory mites

Llusià J., Peñuelas J. (2001) Emission of volatile organic compounds by apple trees under spider mite attack and attraction of predatory mites. Experimental and Applied Acarology. 25: 65-77.
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Doi: 10.1023/A:1010659826193

Resum:

Emission rates of volatile organic compounds (VOCs) from Pirus malus L. subsp. mitis (Wallr.) var. Golden Delicious and var. Starking attacked by the phytophagous mite Panonychus ulmi Koch, and their attractiveness to the predatory mites Amblyseius andersoni Chant and Amblyseius californicus McGregor, were studied during three years. A large variability was found in the emission of individual VOCs depending on the infestation, the apple tree variety and the date. There were larger total VOC emission rates and larger total VOC leaf concentrations in apple trees attacked by phytophagous mites, especially in the var. Starking. In infested trees of this variety, there were also more predatory mites. An olfactometer assay showed that predatory mites preferentially chose branches infested by Panonychus ulmi (85% went to infested branches vs 15% to uninfested control branches) indicating that volatiles may be used as cues to find their prey.

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Seasonal patterns of non-terpenoid C6-C10 VOC emission from seven Mediterranean woody species

Peuelas J., Llusià J. (2001) Seasonal patterns of non-terpenoid C6-C10 VOC emission from seven Mediterranean woody species. Chemosphere. 45: 237-244.
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Doi: 10.1016/S0045-6535(00)00572-5

Resum:

The seasonal pattern of non-terpenoid C6-C10 VOC emission by seven Mediterranean woody species (Bupleurum fruticosum, Cistus albidus, Pinus halepensis, Arbutus unedo, Erica arborea, Quercus coccifera, and Q. ilex) was studied under field conditions. Branch chamber samples were sorbed on carbotrap and analyzed by thermal desorption in combination with GC-MS. These non-terpenoid C6-C10 VOC emissions were large, almost of similar magnitude to those of terpenes. Overall, maximum values were recorded in spring and summer (up to 12 μg g-1 DM h-1 in Q. ilex) and minimum values in autumn and winter (up to 5 μg g-1 DM h-1 in Q. ilex). These C6-C10 VOC emissions represented 2.82% of the photosynthetic C fixation in summer and 0.22% in winter. Some compounds such as 2-ethoxyethyl acetate were emitted by most species, others such as 3-hexen-1-o1, phenol or decanal were significantly emitted only by few species. The greatest diversity of emitted non-terpenoid C6-C10 VOCs was observed in spring and in Q. ilex. Temperature seemed a strong driver of these seasonal changes but other species-specific and seasonal factors seem involved. These results indicate that C6-C10 non-terpenoid VOCs contribute a rather significant fraction of the total biogenic VOC flux from these Mediterranean species, especially in spring and summer, and therefore should be considered in VOC emission inventories and in model predictions of tropospheric chemistry. © 2001 Elsevier Science Ltd. All rights reserved.

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