1 research outputs found
Changes in leaf morphology and composition with future increases in CO2 and temperature revisited. Wheat in field chambers
Whether leaf morphology is altered by future increases in atmospheric CO2 and
temperature has been re-examined during three years in wheat grown in field
chambers at two levels of nitrogen supply. Flag leaf fresh and dry mass, area,
volume, and ratios of these parameters, as well as the contents of water, chlorophyll,
non-structural carbohydrates and nitrogen compounds have been determined at
anthesis and 14 days later. High CO2 decreased, rather than increased as reported in
the literature, leaf mass per area and leaf density, and increased water content per
area and volume and water percentage. Warmer temperatures also decreased leaf
mass per area, but did not affect density or water per area or volume, while they
increased water percentage. Nitrogen supply did not change CO2 and temperature
effects on leaf morphology. Non-structural carbohydrates increased and nitrogen
compounds decreased in elevated CO2, and the sum of these compounds decreased
with warmer temperatures. These changes in composition did not account for
modifications of leaf morphology. We conclude that increases in atmospheric CO2
and temperature after leaf initiation can decrease leaf mass per area, and elevated
CO2 can also decrease leaf density, due to decreases in leaf structural compounds.
The functional significance of these changes is probably a decrease in photosynthetic
capacity per unit leaf area.E.G. and D.G. were the recipients of I3P-European Social Fund and Junta de
Castilla y León fellowships, respectively. We thank the staff of this Institute’s
experimental farm for technical assistance in crop husbandry. This work has been
funded by the Spanish National Research and Development Programme- European
Regional Development Fund, ERDF (Project BFI2003-01277).Peer reviewe