ibclogo XVI International Botanical Congess


Abstract Number: 3728
Session = 20.16.6


TEMPERATURE DEPENDENCE OF AUXIN AND CYTOKININ RESPONSES OF CULTURED GUARD CELL PROTOPLASTS (GCP) OF NICOTIANA GLAUCA


G. Tallman, J. Upton & C.F. Tay, Dept. of Biology, Willamette Univ., Salem, OR 97301 USA


GCP cultured for 1 wk at 32 °C complete the cell cycle. Both auxin and cytokinin are required for GCP cultured at 32 °C to survive. GCP cultured similarly at 38 °C grow but do not divide. At 38 °C in media containing 0.1 µM abscisic acid (ABA), cultured GCP neither grow nor divide, but remain differentiated. Whether ABA is present or not, at 38 °C cell survival is high (70-80%) even in media lacking auxin and/or cytokinin. Thus, GCP cultured at 38 °C in media ± ABA do not advance far enough into the cell cycle to reach the stage at which auxin and cytokinin are required for high survival. Preliminary data suggest that ABA may act by reducing levels of a heat shock protein 90 homolog similar to one required by yeasts to complete the cell cycle. Supported by NSF MCB-9696156.


HTML-Version made 7. July 1999 by Kurt Stüber