M. Ridolfi et al., EFFECTS OF POTASSIUM AND CALCIUM DEFICIENCIES ON STOMATAL FUNCTIONINGIN INTACT LEAVES OF VICIA-FABA, Canadian journal of botany, 72(12), 1994, pp. 1835-1842
The effects of potassium or calcium deficiency on stomatal functioning
were investigated in Vicia faba L. plants grown hydroponically. In th
e leaves of plants grown with 1 mM K+, stomatal opening occurred in li
ght with either normal or CO2-free air; K+ and Cl- accumulations in gu
ard cells were similar to those of the control plants grown with 5 mM
K+. With the zero K+ treatment, stomatal apertures were not affected,
while K+ and Cl- guard cell concentrations fell to 30% of the control
values. These results may indicate that other solutes contribute to th
e lowering of osmotic potential during opening. Stomata of calcium-def
icient plants remained fully open in darkness, whereas abscisic acid (
ABA) supply induced a partial stomatal closing movement. Therefore, ca
lcium deficiency inhibited the process(es) linked with the perception
of darkness and stomatal closure. On the other hand, stomatal sensitiv
ity to ABA was only partially affected.