Effects of preconditioning on electrolyte leakage and lipid composition in black spruce (Picea mariana) stressed with polyethylene glycol

Abstract

T, J. 1990. Effects of preconditioning on electrolyte leakage and lipid composition in black spruce {Picea mariana) stressed with polyethylene glycol. -Physiol. Plant. 79: 71-77.Black spruce {Picea mariana Mill. B. S. P.) rooted cuttings were grown in solution culture and preconditioned by osmotically stressing plants with polyethylene glycol. After relief from preconditioning stress, water relations, membrane leakiness, and the composition of lipids and fatty acids were compared in preconditioned and control, unconditioned plants. Both groups of plants were subsequently subjected to a severe osmotic stress with polyethylene glycol and examined again. Osmotic stress decreased shoot water potentials and increased the leakage of electrolytes from shoots of stressed, compared with unstressed, plants. However, both unstressed and stressed preconditioned plants leaked less electrolytes compared with unconditioned plants. Changes in steroi, phospholipid and glycolipid composition were observed in preconditioned unstressed and stressed plants. Steroi and phospholipid levels declined as a result of stress, and preconditioning resulted in a decline in steroi: phospholipid ratios in plants.

New Plant Growth Regulators Protect Photosynthesis and Enhance Growth Under Drought of Jack Pine Seedlings

“…Results were expressed as Membrane Injury Index, the % of total electrolytes (i.e., those that leaked from heat-killed needles). These techniques are described by Zwiazek and Blake (1990) and Odlum and Blake (1996).…”

“…Loss of membrane integrity was suggested by the increase in electrolyte leakage in black spruce under drought (Fan andBlake 1994, Tan andBlake 1993). Severe dehydration causes a decline in sterols, lipids, and their ratio (Zwiazek and Blake 1990). Drought-induced membrane leakage may explain alteration in membrane constituents.…”

Hydrogen fluoride effects on plasma membrane composition, ATPase activity and cell structure in needles of eastern white pine (Pinus strobus) seedlings

“…The fractions containing sterols were evaporated under nitrogen, the residue dissolved in 0.5 ml pyridine and trimethylsilyl derivatives of sterols were made by adding 0.1 ml trimethylchlorosilane followed by 0.2 ml hexamethyldisilazane (Zwiazek and Blake 1990). Sterols were analyzed using a Hewlett Packard 5890 gas chromatograph equipped with a 30-m-long, 0.25-mm internal diameter DB-5 column (J&W Scientific, Folsom, Calif., USA).…”

Ecophysiology and field performance of black spruce (Picea mariana): a review

“…Zwiazek and Blake (1990a) found that the osmotic potential of preconditioned black spruce seedlings was lower than that of unconditioned plants before and during subsequent exposure to osmotic stress with polyethylene glycol (PEG (Lawlor, 1970). Zwiazek and Blake (1990b) (Dang et al 1991(Dang et al , 1992. Full recovery of the photosynthetic apparatus after a summer frost may take several weeks (Pharis et al, 1970).…”