Effect of Salt Stress, Proline, and Polyamines on Seed Germination of Opuntia streptacantha

In this study we conducted experiments in order to determine whether polyamines (putrescine, spermidine, and spermine) and proline treatments help to break seed dormancy of Opuntia streptacantha and also if they facilitate seed germination under salt stress. The results showed that 1mM proline stimulated a better germination percentage as compared to untreated seeds, although the difference was not statistically significant.. With respect to polyamines, they did not break seed dormancy. On the other hand, salinity affected seed germination at the higher concentrations (50 and 75 mM NaCl) used, whereas, at 25 mM NaCl, results were similar to the control. The germination percentage in the treatments with proline (1 and 10 mM) and with polyamines (1 mu M each) diminished significantly when increasing the concentration of NaCl. The exception was spermine treatment, which alleviates seed germination at the higher concentration of NaCl used (75 mM).