Resumen
Impatiens walleriana is a decorative horticultural plant species. Commercial production requires that the plants be brought to market, often accompanied by reduced water content during transport. Drought significantly affects metabolic processes in plants. The effects of polyethylene glycol (PEG)-induced water deficit on shoots of I. walleriana were investigated using different mechanisms at the biochemical level. In addition, the potential water deficit-ameliorating effect of sodium nitroprusside (SNP) was tested. Shoots of I. walleriana were initially grown on MS media supplemented with SNP (50, 100 and 250 µM). After pre-treatments, shoots were further transferred to media supplemented with PEG8000 (3%) and/or SNP (50, 100 and 250 µM). Water deficit conditions increased proline, photosynthetic pigments, malondialdehyde (MDA), H2O2, total phenolic content and antioxidant activity. In addition, PEG-induced water deficit increased superoxide dismutase (SOD) and peroxidase (POX) activities but decreased catalase (CAT) activity. SNP did not significantly affect photosynthetic pigments and total phenolic content but increased proline accumulation, MDA and H2O2 content, especially when applied simultaneously with PEG. Moreover, none of the investigated SNP pretreatments significantly altered the activities of SOD, POX, and CAT in I. walleriana. The results indicate that exogenous application of SNP effectively alleviated water deficit stress in shoots of I. walleriana grown in vitro.