In this article:
Sultana vines were used to study diurnal changes of stomatal patchiness under the natural ambient conditions of South Australia.
Non-homogenous aperture of stomata (patchiness) was determined by an infiltration technique and by counting infiltrated patches. Stomatal conductance was linearly related to the number of patches with open stomata.
Both parameters increased in the early morning and decreased thereafter. In the afternoon stomatal conductance and the number of patches with open stomata remained at a low level.
When dark adapted leaves were exposed to sun light the number of patches with open stomata increased from 23 to 143 cm2 within 15 min, indicating that besides several stress factors light induces non-homogenous stomatal opening.
It is assumed that stomatal action of single patches is autonomous, i.e. stomata of single patches will regulate water loss and C02 uptake according to local changes of ambient and endogenous conditions.
Stomatal Patchiness of Field-grown Sultana Leaves: Diurnal Changes and Light Effects
1996, Vitis, vol 35, issue 1, pages 7-10