Abstract The current study was aimed to solve the problem of browning in Iranian seedless barberry in vitro culture by using a variety of different approaches. As such, several experiments were carried out. The results revealed that addition of 225mg/l citric acid+ 50mg/l ascorbic acid could alleviate phenol browning compared to control. Presoaking of explants in 300mg/l citric acid solution for 30min and culturing them in media containing 225mg/l citric acid could further reduce browning rate. Results related to the effect of sampling time indicated that explants cut off in April showed the lowest browning rate and those cut off in January, February and March showed the highest browning rate. Effects of conditions related to stock plant were also investigated, and the results displayed that explants harvested from upper position of current-year shoot and sucker showed the lowest browning rates, respectively, while those collected from lower position of one- and two-year old shoots exhibited the highest browning rate, respectively. Data obtained from shoot color and diameter also demonstrated that explants taken from pinkish-colored shoots with small diameter showed the lowest browning rate and those collected from dark brown-colored shoots with large and very large diameter contained the highest browning rates. Use of 8-hydroxyquinoline and Fe-EDDHA for reduction of browning was investigated for the first time, and interestingly the results showed that both compounds, in particular 8-hydroxyquinoline, caused a significant reduction in phenol exudation. More interestingly, they could cause a significant increase in bud break rate. Furthermore, phenol exudation and peroxidase activity in treatments supplemented with 8-hydroxyquinoline and Fe-EDDHA were lower than those in treatments containing antioxidants.

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