Quantifying stem water content in hardened seedlings of wood species

Resumo

The work aimed to compare destructive and non-destructive methodologies in quantifying stem water content in Nectandra grandiflora and Inga sessilis seedlings hardened with 50 μmol L^-1 of methyl jasmonate or 20 daily stem bending for eight weeks plus a control treatment. Subsequently to the hardening treatments, seedlings were subjected to water restriction for up to 30 days. Stem water content was evaluated biweekly at zero (T0), 15 (T15) and 30 (T30) days under water restriction using the destructive and non-destructive methods. For I. sessilis at T0, both evaluations indicated lower stem water content for the stem bending seedlings, however with the non-destructive method, seedling from the two hardening treatments did not differ from the control. In T15, the treatments were similar according to non-destructive method, while with the destructive method methyl jasmonate ensured greater stem water content. At T30, both quantification methods indicated control seedlings with lower stem water content with both hardening treatments yielding similar results. For N. grandiflora, the destructive method did not differ between hardening treatments at T0, while the control seedlings presented lower stem water content with similar results between hardening treatments according to the non-destructive method. At T15, hardening treatments did not differ according to both quantification of water stem methodologies. At thirty days under water restriction, both hardening treatments were efficient in maintaining greater stem water content regardless of the quantification method. Replacing the destructive method with the non-destructive proved to be unfeasible with hardening seedlings of the two species.