Cover Illustration: DNA fragmentation characteristic of programmed cell death (PCD) was detected in NaCl-treated determinate primary roots of Stenocereus gummosus (Cactaceae) using the terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL) assay. Nuclei in the bottom left image, a longitudinal section of a root tip after PCD-inducing NaCl treatment, fluoresce blue after 4'-6-diamidino-2-phenylindole (DAPI) staining. Those nuclei undergoing DNA fragmentation fluoresce green in the same section (top left, fluorescein-isothiocyanate [FITC] staining). During root development, PCD was not involved in meristem exhaustion, but did occur in root-hair and root-cap cells. Both DNA and nuclear fragmentation were detected in a root-hair cell (right: top, FITC; middle, DAPI). Dead remnants (red-fluorescing nuclei, propidium-iodine stain, bottom right) of the root cap lie below a root that has terminated growth. See Shishkova and Dubrovsky: Developmental programmed cell death in primary root of Sonoran Desert Cactaceae, pp. 1590-1594 in this issue. Photo credit: Svetlana Shishkova and Joseph Dubrovsky.
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Copyright © 2005 by the Botanical Society of America, Inc.
