Role of superoxide, lipid peroxidation and superoxide dismutase in membrane perturbation during loss of viability in seeds of <i>Shorea robusta</i> Gaertn.f.

SUMMARY Recalcitrant seeds of Shorea robusta (sal) exhibit 100% viability up to 4 d after maturity. The rapid loss of viability after 4 d is associated with the reduction in moisture content below the lowest safe moisture content (37°o). Seed becomes non‐viable on 8 d. Increased leakage of electrolytes in seeds and lipid peroxidation in embryonic axes was discernible immediately from 0 d. In embryonic axes, very low levels of superoxide (O 2 − ) were maintained up to 4 d and a sharp increase was registered up to 7 d. It is suggested that loss of moisture content in sal seeds below 37% (after 4 d) induces substantial leakage loss probably due to increased lipid peroxidation and O 2 − ) radical formation which are responsible for severe membrane perturbations leading to rapid loss of viability. In embryonic axes SOD activity was recorded only in 100% viable seeds.