Metabolic responses to water deficit in two Eucalyptus globulus clones with contrasting drought sensitivity

• Published in: Tree physiology 2006-02, Vol.26 (2), p.239-248
• Main Authors: Shvaleva, A.L, Costa e Silva, F, Breia, E, Jouve, L, Hausman, J.F, Almeida, M.H, Maroco, J.P, Rodrigues, M.L, Pereira, J.S, Chaves, M.M
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological - physiology; antioxidants; Ascorbate Peroxidases; beta Carotene - metabolism; Biomass; Carbohydrate Metabolism; Carbohydrates - analysis; Catalase - metabolism; clones; Dehydration; Disasters; drought tolerance; enzyme activity; Eucalyptus - growth & development; Eucalyptus - metabolism; Eucalyptus globulus; genetic variation; Glutathione Reductase - metabolism; leaf water potential; leaves; metabolism; Osmosis - physiology; osmotic pressure; Peroxidases - metabolism; Plant Leaves - anatomy & histology; Plant Leaves - growth & development; Plant Leaves - metabolism; plant pigments; Plant Proteins - analysis; Plant Proteins - metabolism; Plant Roots - anatomy & histology; Plant Roots - growth & development; Plant Roots - metabolism; proline; Proline - metabolism; quantitative analysis; roots; sugars; Superoxide Dismutase - metabolism; Water - metabolism; water stress; Xanthophylls - metabolism; Zeaxanthins
• ISSN: 0829-318X; 1758-4469
• DOI: 10.1093/treephys/26.2.239

We compared the metabolic responses of leaves and roots of two Eucalyptus globulus Labill. clones differing in drought sensitivity to a slowly imposed water deficit. Responses measured included changes in concentrations of soluble and insoluble sugars, proline, total protein and several antioxidant enzymes. In addition to the general decrease in growth caused by water deficit, we observed a decrease in osmotic potential when drought stress became severe. In both clones, the decrease was greater in roots than in leaves, consistent with the observed increases in concentrations of soluble sugars and proline in these organs. In roots of both clones, glutathione reductase activity increased significantly in response to water deficit, suggesting that this enzyme plays a protective role in roots during drought stress by catalyzing the catabolism of reactive oxygen species. Clone CN5 has stress avoidance mechanisms that account for its lower sensitivity to drought compared with Clone ST51.