Morpho-physiological changes in alstroemeria ʿFrostyʾ cut flowers treated with sodium nitroprusside and thymol

Increasing the marketability of cut flowers is very important from an economic point of view and alstroemeria cut flowers are considered as one of the most important cut flowers in Iran and worldwide. To investigate the effect of different concentrations of sodium nitroprusside (0, 50, and 100 μM) and thymol (0, 50, and 100 mg L -1) on the morpho-physiological traits of alstroemeria, a factorial experiment was conducted based on a completely randomized design. The longest vase life (16.3 days) was observed in the treatment with 100 µM sodium nitroprusside with or without thymol. In the treatments without sodium nitroprusside, no changes were observed in flower longevity with increasing thymol concentration. The interaction effects of sodium nitroprusside and thymol on relative fresh weight on days 5, 7, 9, and 13 and solution uptake were significant in all days. For the treatments with 50 and 100 µM sodium nitroprusside along with 50 mg L-1 thymol, there was an upward trend in solution absorption and relative fresh weight until the fifth day and a downward trend thereafter. The lowest value for relative fresh weight and solution absorption was observed in the control treatment. The highest values of chlorophyll a (0.16 mg L-1), chlorophyll b (0.078 mg L-1), and total chlorophyll (0.238 mg L-1) were observed in the 100 µM sodium nitroprusside and 50 mg L-1 thymol treatments. In the treatments with 100 μM sodium nitroprusside without or with thymol, the lowest amount of bacteria (3.51-62.3 log10 CFU/ml) and the highest amount of this indicator (3.88 log10 CFU/ml) was detected in the control treatment. No significant difference in dry weight was observed in the treatments without sodium nitroprusside and 50 μM sodium nitroprusside with increasing thymol concentration, but the highest amount of dry weight was observed in the treatment with 100 μM sodium nitroprusside and 50 mg L-1 thymol. The results of this experiment suggested the use of 100 μM sodium nitroprusside with or without thymol to extend vase life and reduce chlorophyll degradation in alstroemeria cut flowers.