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

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 (Ψ = -1MPa, Ψ = -2 MPa) and a control treatment (Ψ = -0.03 MPa) were tested. Relative water content (RWC) was markedly low at the end of the experiment. Both 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 rootshoot (stem + needles) ratio were increased by water deficit. Opposite 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 weight. The growing media caused additional stress to the plants, thus comparisons with other drought protocols should be made carefully.

Bibliographic Details

Main Authors:	López, R., Aranda García, Ismael, Gil, L.
Format:	artículo biblioteca
Language:	English
Published:	CSIC - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA) 2009
Subjects:	Hydroponic culture, Polyethylene glycol, Biomass partitioning, Maritime pine, Canary Island pine,
Online Access:	http://hdl.handle.net/20.500.12792/2429 http://hdl.handle.net/10261/291761
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