Effects of nitric oxide treatment on active oxygen metabolism and flesh lignification in bamboo shoots

摘要

The effects of nitric oxide (NO) on active oxygen metabolism and flesh lignification in fresh-cut bamboo shoots (Phyllostachys violascens) were investigated. To determine the optimum concentration of sodium nitroprusside (SNP; a donor of NO) treatment, shoots were treated for 1 h in 0, 0.1, 0.5, or 1.0 mM SNP, then stored in perforated plastic bags for 10 d at 20 degrees C, and 80 - 90% relative humidity. The application of 0.5 mM SNP was most effective in preventing an increase in shoot firmness and allied accumulations of lignin and cellulose. Treatment with 0.5 mM SNP also inhibited the typical, storage-related decreases in shoot superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities. In addition, SNP treatment reduced the increase in peroxidase (POD) activity in shoots. SNP treatment maintained low levels of production of superoxide anions (O-2(-)) and hydrogen peroxide (H2O2), while inhibiting the accumulation of malondialdehyde (MDA) and an increase in membrane permeability in shoots. Our results suggest that pre-treatment with 0.5 mM SNP could maintain the balance between the formation and the removal of active oxygen species in bamboo shoots. This appears to delay lipid peroxidation, and thereby prevent the development of flesh lignification and the associated decline in post-harvest shoot quality.