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Advisor(s)
Abstract(s)
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
towater 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.
Description
Keywords
Antioxidant enzymes Osmotic potential Proline Sugars Water stress
Citation
Tree Physiology, 26, 239-248