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Elevated CO 2 increases wheat cer, leaf and tiller development, and shoot and root growth
Author(s) -
McMaster G. S.,
LeCain D. R.,
Morgan J. A.,
Aiguo L.,
Hendrix D. L.
Publication year - 1999
Publication title -
journal of agronomy and crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.095
H-Index - 74
eISSN - 1439-037X
pISSN - 0931-2250
DOI - 10.1046/j.1439-037x.1999.00325.x
Subject(s) - tiller (botany) , shoot , photosynthesis , canopy , biology , agronomy , poaceae , phenology , dry weight , carbon dioxide , starch , biomass (ecology) , horticulture , botany , biochemistry , ecology
Whole‐plant responses to elevated CO 2 throughout the life cycle are needed to understand future impacts of elevated atmospheric CO 2 . In this study, Triticum aestivum L. leaf carbon exchange rates (CER) and carbohydrates, growth, and development were examined at the tillering, booting, and grain‐filling stages in growth chambers with CO 2 concentrations of 350 (ambient) or 700 (high) μmol mol −1. Single‐leaf CER values measured on plants grown at high CO 2 were 50% greater than those measured on plants grown at ambient CO 2 for all growth stages, with no photosynthetic acclimation observed at high CO 2 . Leaves grown in high CO 2 had more starch and simple sugars at tillering and booting, and more starch at grain‐filling, than those grown in ambient CO 2 . CER and carbohydrate levels were positively correlated with leaf appearance rates and tillering (especially third‐, fourth‐ and fifth‐order tillers). Elevated CO 2 slightly delayed tiller appearance, but accelerated tiller development after appearance. Although high CO 2 increased leaf appearance rates, final leaf number/culm was not effected because growth stages were reached slightly sooner. Greater plant biomass was related to greater tillering. Doubling CO 2 significantly increased both shoot and root dry weight, but decreased the shoot to root ratio. High CO 2 plants had more spikes plant −1 and spikelets spike −1 , but a similar number of fertile spikelets spike −1. Elevated CO 2 resulted in greater shoot, root and spike production and quicker canopy development by increasing leaf and tiller appearance rates and phenology.