Specification of adaxial and abaxial stomata, epidermal structure and photosynthesis to CO2 enrichment in maize leaves

Abstract

Acclimation to CO2 enrichment was studied in maize plants grown to maturity in either 350 or 700 microl l-1 CO2. Plants grown with CO2 enrichment were significantly taller than those grown at 350 microl l-1 CO2 but they had the same number of leaves. High CO2 concentration led to a marked decrease in whole leaf chlorophyll and protein. The ratio of stomata on the adaxial and abaxial leaf surfaces was similar in all growth conditions, but the stomatal index was considerably increased in plants grown at 700 microl l-1 CO2. Doubling the atmospheric CO2 content altered epidermal cell size leading to fewer, much larger cells on both leaf surfaces. The photosynthesis and transpiration rates were always higher on the abaxial surface than the adaxial surface. CO2 uptake rates increased as atmospheric CO2 was increased up to the growth concentrations on both leaf surfaces. Above these values, CO2 uptake on the abaxial surface was either stable or increased as CO2 concentration increased. In marked contrast, CO2 uptake rates on the adaxial surface were progressively inhibited at concentrations above the growth CO2 value, whether light was supplied directly to this or the abaxial surface. These results show that maize leaves adjust their stomatal densities through changes in epidermal cell numbers rather than stomatal numbers. Moreover, the CO2-response curve of photosynthesis on the adaxial surface is specifically determined by growth CO2 abundance and tracks transpiration. Conversely, photosynthesis on the abaxial surface is largely independent of CO2 concentration and rather independent of stomatal function.

Maximum leaf conductance driven by CO 2 effects on stomatal size and density over geologic time

“…5F). It mirrors the effects of changes in atmospheric CO 2 on the stomata of extant plants (12,13,17,18) and holds even for grasses evolving in the low-CO 2 atmosphere of the Miocene.…”

Physiological and molecular alterations in plants exposed to high [CO2] under phosphorus stress

“…Maize leaves exposed to high [CO 2 ] showed a reduction in the number of epidermal cells, whereas the stomatal index was increased (Driscoll et al, 2006 …”

The Effect of Irradiating Adaxial or Abaxial Side on Photosynthesis of Rose Leaves

“…Most of the studies on the response to light stimuli to the different leaf sides have been carried out on C4 metabolism plants (Driscoll et al, 2006;Soares et al, 2008) more than on C3 species (Morr and O'Leary, 1984;Wang et al, 2008). Although, several researches have been reported on field grown plant species (Terashima, 1986;Postl and Bolhar-Nordenkampf, 1992), only little information seems to be available on greenhouse crops.…”