Effects of water potential in the root growth of seedlings of Agave salmiana otto ex Salm-Dyck

The aim of this study was to characterise the effects of substrate water potential (psi(W)) of the physiological and biophysical characteristics of root seedlings of Agave salmiana Otto ex Salm-Dyck under laboratory conditions. Seedlings of 3-4cm root length were maintained in vermiculite at psi(W) of -0.03, -0.65, -1.48 and -2.35MPa for 24h. At the end of this period a group of seedlings was re-hydrated and from another group roots were harvested and the elongation, dry and fresh weight, and proline content were quantified. Electrical conductivity, pH and the concentrations of Cu, Fe, K, Mn, Na and Zn were determined in the root re-suspension media. The effect of re-hydration on root growth after 24h was evaluated. The low T, of the substrate did not affect significantly root length, but fresh weight diminished (23.5 to 49.2%), and the damage index increased 36.0%. The ions leached to the re-suspension media were not significantly affected and the proline root content increased from 1.6 to 2.11mumol (.) mg(-1) of dry matter. Roots continued growing after rehydration.