Arundo donax L. response to low oxygen stress

Production of nonfood species is promoted to marginal, degraded lands abandoned by mainstream agricultural, where extremes in water availability (droughts and floods) have increased frequency and intensity and account for severe reductions in yields. A metabolic analysis of anoxic and hypoxic stress response was performed in a time-course experiment on Arundo donax L., a perennial rhizomatous grass identified as a leading candidate crop for lignocellulosic feedstock in the Mediterranean environment, due to its positive energy balance, and low ecological/agro-management demands. Tolerance to oxygen deprivation was determined after reoxygenation. Giant reed displayed time-dependent reduction in absolute growth and alterations in the derived physiological attributes under low oxygen stress. Our results show that although giant reed's responses to anoxic and hypoxic treatments share a common energy crisis related to the anaerobic metabolism, they differ in terms of ADH activity and related gene response. In leaves and roots tissues, the expression of this anaerobic gene was strongly enhanced under anoxia, whereas the ADH expression under submergence condition was relatively low. The activity profiles of ADH were not completely reflected in the expression patterns in either tissue. A high basal activity of the enzyme was recorded in both leaves and roots in normoxic tissues. In leaves, the treatments did not significantly affect ADH activity, remaining relatively stables at low levels during the time-course experiment. A different pattern of ADH was observed in roots, with a stronger, albeit transient, induction in both oxygen deficiency treatments.