© 1990 Heron Publishing—Victoria, Canada
Selection and physiology of cell cultures of Douglas-fir grown under conditions of water stress
T. Leustek (1, 2) and E. G. Kirby (1)
1. Department of Biological Sciences, Rutgers University, Newark, NJ 07102, USA / 2. Roche Institute of Molecular Biology, Nutley, NJ 07110, USA / Received August 2, 1989
Summary
Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) cell cultures sampled 3, 6, or 9 days after subculture in nutrient medium were able to survive subsequent
subculture in a medium containing 15% polyethylene glycol (PEG) (Mr 6000–8000) (–1.21 MPa), whereas cell sampled 12 or 16 days after subculture in nutrient medium became senescent when transferred
to a medium containing 15% PEG. Cells sampled after subculture for 3, 6, or 9 days in nutrient medium had lower fresh weight/dry
weight ratios, lower osmotic potentials, smaller cell diameters, and higher turgor pressures than cells sampled after 12 or
16 days subculture in nutrient medium.
Cells surviving subculture to a medium containing 15% PEG did not increase in dry weight for 5 weeks even though the medium
was exchanged every 7 days. After 5 weeks, however, dry weight growth resumed and reached 75% of the level attained by control
cells grown on PEG-free medium. Long-term growth on a medium containing 15% PEG (PEG-selected cells) could only be sustained
if the medium was supplemented with 30 mM glutamine. The PEG-selected cells grew in small clusters, were isodiametric, and
had chlorophyll contents 50% higher than unselected cells. The PEG-selected cells also
showed lowered cellular osmotic potentials, presumably due to osmoregulation. Turgor pressures of PEG-selected cells were
greater than or equal to those of unselected cells.
