Anion Metabolism as Correlated with the Volume Changes of Guard Cell Protoplasts

Isolated and purified guard cell protoplasts of starch-containing (Vicia faba) and starch-lacking (Allium cepa) stomata were used to study the metabolism of malate and Cl- anions as correlated with the K+-induced swelling of protoplasts. The correlation between swelling and malate synthesis in starch-containing and the inhibition of this correlation in starch-lacking guard cell protoplasts were demonstrated. A model system was proposed involving the role of malate and its place of synthesis in these two contrasting stomatal types.