Premium
Stomatal index responses of Agrostis canina to CO 2 and sulphur dioxide: implications for palaeo‐[CO 2 ] using the stomatal proxy
Author(s) -
Haworth Matthew,
Gallagher Angela,
ElliottKingston Caroline,
Raschi Antonio,
Marandola Danilo,
McElwain Jennifer C.
Publication year - 2010
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2010.03403.x
Subject(s) - fumigation , environmental science , botany , horticulture , biology
Summary• Stomatal index values of fossil plants are widely used in reconstructing palaeo‐[CO 2 ]. This depends upon the assumption that the stomatal index is determined by the atmospheric concentration of CO 2 ([CO 2 ]). This study investigates whether fumigation with, and resistance to, sulphur dioxide (SO 2 ) induces a reduction in the stomatal index that may affect stomatal reconstructions of palaeo‐[CO 2 ] coinciding with episodes of global‐scale volcanism. • Agrostis canina from Mefite di Ansanto, Italy, grow in atmospheres of elevated‐[CO 2 ], SO 2 and hydrogen sulphide (H 2 S). Mefite A. canina were compared with a control population in a ‘common‐garden’ experiment and a controlled‐environment study under elevated‐[CO 2 ] and SO 2 fumigation. • In A. canina , resistance to toxic volcanic gases is not associated with reduced stomatal index, and fumigation with SO 2 does not cause a decrease in stomatal initiation. The two populations of A. canina analyzed in this study exhibit different stomatal index–[CO 2 ] ‘responses’, with control plants showing a reduction in stomatal index and Mefite plants showing no response. • Stomatal reconstructions of palaeo‐[CO 2 ] during past episodes of global‐scale volcanism probably reflect atmospheric [CO 2 ] and not [SO 2 ]. The lack of a reduction in the stomatal index in response to elevated [CO 2 ] in the Mefite plants, suggests that resistance to toxic gases and/or long‐term growth at high [CO 2 ] reduces, or negates, sensitivity of the stomatal index–[CO 2 ] relationship, or that stomatal index–[CO 2 ] in the Mefite plants is attuned to [CO 2 ] fluctuations at much higher concentrations.