Comparative field study of Quercus ilex and Phillyrea latifolia: photosynthetic response to experimental drought conditions. Ogaya, R. and Peñuelas, J. Environmental and Experimental Botany, 50(2):137–148, October, 2003.
Comparative field study of Quercus ilex and Phillyrea latifolia: photosynthetic response to experimental drought conditions [link]Paper  doi  abstract   bibtex   
Quercus ilex and Phillyrea latifolia growing in a holm oak forest in Prades mountains (NE Spain) were subjected to experimental drought conditions. Soil water availability was reduced about 15% by plastic strips and funnels that partially excluded rain throughfall and by ditch exclusion of water runoff. Diurnal courses of maximum photochemical efficiency of PSII (Fv/Fm), apparent photosynthetic electron transport rate (ETR), net photosynthetic rate (A), transpiration rate (E) and water use efficiency (WUE) were measured in sunlit and shade leaves of both species during 2 years. Moreover, the responses of photosynthetic rates to PPFD and CO2 concentrations were also measured. Q. ilex experienced lower E rates and higher A rates and WUE than P. latifolia throughout the experimental period, but during summer drought these differences disappeared. Q. ilex exhibited a less cold sensitive behavior whereas P. latifolia showed a more heat Á/drought resistant behavior. Under severe summer drought conditions none of the two species was able to reach a positive carbon gain. Drought treatment produced a slight decrease in Fv/Fm values of Q. ilex plants and a strong decrease in Fv/Fm values of P. latifolia only in winter 2000, when drought stress coincided with cold stress. Drought treatment produced also a slight decrease in ETR values of both species. During midday, A and E rates decreased in drought plots in both species associated to lower photochemical efficiencies. In those drought plots, only P. latifolia was able to increase WUE by reducing transpiration losses during midday. Both species tended to present higher A rates for a given soil humidity in drought than in control plots. However, whereas Q. ilex A rates increased with soil humidity, P. latifolia A rates did not increase above 17% soil humidity, showing no water availability response above such threshold. It is very likely that mesic species such as Q. ilex lose competitive advantage in the drier environment forecasted for next decades than the more xeric P. latifolia .
@article{ogaya2003Comparative,
	title = {Comparative field study of {Quercus} ilex and {Phillyrea} latifolia: photosynthetic response to experimental drought conditions},
	volume = {50},
	issn = {00988472},
	shorttitle = {Comparative field study of {Quercus} ilex and {Phillyrea} latifolia},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S0098847203000194},
	doi = {10.1016/S0098-8472(03)00019-4},
	abstract = {Quercus ilex and Phillyrea latifolia growing in a holm oak forest in Prades mountains (NE Spain) were subjected to experimental drought conditions. Soil water availability was reduced about 15\% by plastic strips and funnels that partially excluded rain throughfall and by ditch exclusion of water runoff. Diurnal courses of maximum photochemical efficiency of PSII (Fv/Fm), apparent photosynthetic electron transport rate (ETR), net photosynthetic rate (A), transpiration rate (E) and water use efficiency (WUE) were measured in sunlit and shade leaves of both species during 2 years. Moreover, the responses of photosynthetic rates to PPFD and CO2 concentrations were also measured. Q. ilex experienced lower E rates and higher A rates and WUE than P. latifolia throughout the experimental period, but during summer drought these differences disappeared. Q. ilex exhibited a less cold sensitive behavior whereas P. latifolia showed a more heat Á/drought resistant behavior. Under severe summer drought conditions none of the two species was able to reach a positive carbon gain. Drought treatment produced a slight decrease in Fv/Fm values of Q. ilex plants and a strong decrease in Fv/Fm values of P. latifolia only in winter 2000, when drought stress coincided with cold stress. Drought treatment produced also a slight decrease in ETR values of both species. During midday, A and E rates decreased in drought plots in both species associated to lower photochemical efficiencies. In those drought plots, only P. latifolia was able to increase WUE by reducing transpiration losses during midday. Both species tended to present higher A rates for a given soil humidity in drought than in control plots. However, whereas Q. ilex A rates increased with soil humidity, P. latifolia A rates did not increase above 17\% soil humidity, showing no water availability response above such threshold. It is very likely that mesic species such as Q. ilex lose competitive advantage in the drier environment forecasted for next decades than the more xeric P. latifolia .},
	language = {en},
	number = {2},
	urldate = {2018-06-09},
	journal = {Environmental and Experimental Botany},
	author = {Ogaya, Romà and Peñuelas, Josep},
	month = oct,
	year = {2003},
	pages = {137--148}
}
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