Differential Declines in DNA of Aging Leaf Tissues

Abstract
Leaves from tobacco and peanut were sampled for cytophotometric study from young to senescent stages. Differences in nuclei between tissues developed during aging. Tobacco epidermal cells showed an average loss of approximately one-third of their DNA and peanut epidermis lost more than one-fourth. Mesophyll nuclear DNA declined more slowly than epidermal. These results imply that leaf aging may begin in the epidermis.