The structural nature of Passiflora organensis Gardner leaf variegation

Abstract

In almost all species of the genus Passiflora, the plants in the juvenile stage produce leaves with a different morphology when compared to adult plants. During the juvenile stage, Passiflora organensis typically has variegated leaves, and in adult plants leaves are non-variegated and have extrafloral nectaries. Studies have shown that variegation in plants is not just a color change, but has adaptive functions that can benefit plants. We show here that the variegated leaves observed in P. organensis in the juvenile stage occur due to a mechanism in which intercellular spaces are present between the epidermis and palisade parenchyma cells in the adaxial side of the leaves. We also show that both the green and the white-silverish sectors of the leaves contain well-developed chloroplasts, with no significant differences in the efficiency of Photosystem II. We hypothesize that leaf variegation in P. organensis represents an adaptation to protect juvenile plants from herbivores and environmental stresses.