Speculations on carbon dioxide starvation, late tertiary evolution of stomatal regulation and floristic modernization.
by Robinson J. M. (1994)
Umweltforschungszentrwn Leipzig-Halle, Permoserstr. 15, 04318 Leipzig, Germany
in Plant, Cell and Environment 1994;17: 345–354 – –
Ambient atmospheric CO2 concentration ([CO2]a) has apparently declined from values above 200μmol mol−1 to values below 200μmol mol−1 within the last several million years. The lower end of this range is marginal for C3 plants.
I hypothesize that:
(1) declining [CO2]a imposed a physiological strain on plants, and plant taxa evolving under declining [CO2]a tended to develop compensating mechanisms, including increased stomatal efficiency;
(2) angiosperms were better able to adjust to declining [CO2]a than were gymnosperms and pteridophytes; and
(3) angiosperm adjustment has been uneven.
Fast-evolving taxa (e.g. grasses and herbs) have been better able to adapt to CO2 starvation. If these propositions are true, stomatal adjustment mechanisms should show patterned variation, and a single pattern of stomatal regulation cannot be assumed.