Osmotic adjustment is a significant mechanism of drought resistance in Pinus pinaster and Pinus canariensis

  • R. López Universidad Politécnica de Madrid.Madrid (España)
  • I. Aranda Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria.Madrid (España)
  • L. Gil Universidad Politécnica de Madrid.Madrid (España)
Keywords: PINUS PINASTER, PINUS CANARIENSIS, DROUGHT STRESS, ROOT PRESSURE, OSMOTIC PRESSURE, DROUGHT RESISTANCE, EXPERIMENTATION

Abstract

Mechanisms of drought resistance were studied in two xeric populations of Pinus canariensis and Pinus pinaster. Seedlings were grown in a hydroponic culture for four months. Gradual controlled drought was imposed during two weeks by adding Polyethylene glycol (PEG-6000) to the growing medium. Two levels of water deficit (Psi = -1MPa, Psi = -2 MPa) and a control treatment (Psi = -0.03 MPa) were tested. Relative water content (RWC) was markedly low at the end of the experimenBoth populations showed a high capacity for osmotic adjustment in needles as shown by the osmotic index, 0.63 (1.33 MPa at 80% RWC) for P. canariensis and 0.54 (1.25 MPa at 80% RWC) for P. pinaster. Root growth and root:shoot (stem + needles) ratio were increased by water deficiOpposite patterns of relative biomass allocation were assessed between stressed and control plants. While stressed seedlings assigned more dry matter to roots, non-stressed plants showed a higher relative needle weighThe growing media caused additional stress to the plants, thus comparisons with other drought protocols should be made carefully.

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Published
2009-08-01
How to Cite
LópezR., ArandaI., & GilL. (2009). Osmotic adjustment is a significant mechanism of drought resistance in Pinus pinaster and Pinus canariensis. Forest Systems, 18(2), 159-166. https://doi.org/10.5424/fs/2009182-01059
Section
Research Articles