Growth and cellular patterns in petal epidermis of Antirrhinum

Growth and cellular patterns in petal epidermis of Antirrhinum

Growth and cellular patterns in petal epidermis of Antirrhinum

Analysis of cellular patterns in plant organs provides information about the orientation of cell divisions and predominant growth directions. Raczyńska-Szajgin and Nakielski study patterns in the epidermis of asymmetrical wild-type dorsal petals and symmetrical dorsalized petals of the backpetals mutant of Antirrhinum majus (snapdragon) to determine how growth in initially symmetrical petal primordia leads to the development of mature petals differing in their symmetry. They find that during primordia development a characteristic fountain-like cellular pattern is maintained with only slight modifications, and petal cells divide in non-random directions. These features of the cellular pattern are presumably related to principal directions of growth. Two scenarios are considered to explain how gradual modifications in these directions may contribute to the transition from a symmetric to an asymmetric cellular pattern in the wild type petal.