SUBEPIDERMAL AIR SPACES: BASIS FOR THE PHENOTYPIC EXPRESSION OF THE ARGENTEUM MUTANT OF PISUM

Abstract

The Argenteum ( Arg ) mutant of pea is characterized by a gray‐green, silvery cast of the leaves and stipules. Light and electron microscopy showed that the nature of the silvery cast was due to extensive intercellular air space between the epidermis and palisade parenchyma. Adaxial epidermal strips from mutant leaves were free of palisade cell wall fragments, whereas similar strips from normal leaves had remnants of the torn palisade cells attached to the epidermal cell walls. The periphery of the epidermal‐palisade cell wall interfaces showed a more electron‐opaque middle lamella in the normal leaves than in the Arg mutant leaves.