Cell and Tissue Journal

Abstract Aim: The aim of this study was to investigate the effect of Zinc oxide nanoparticles on growth and physiological characteristics, rosmarinic acid production and the expression of key genes in the biosynthetic pathway of this compound in lemongrass.
Material and Methods: In this study, 30-day-old seedlings of lemongrass were treated with concentrations of 0, 0.06 and 0.12 mg/l Zinc oxide nanoparticles, and then growth parameters, photosynthetic pigments, proline, Glycine betaine, protein, activity of antioxidant enzymes and production of rosmarinic acid were examined. Also, the expression of key genes in the rosmarinic acid biosynthetic pathway was examined by real-time PCR.
Results: The results indicate that Zinc oxide nanoparticles treatment increased chlorophyll photosynthetic pigments, carotenoids and antioxidant activity of this plant. Also, the highest amount of proline and glycine betaine was obtained at a concentration of 12 mg/L of this treatment. Zinc oxide nanoparticles also increased the expression of rosmarinic acid biosynthetic pathway genes (TAT and 4-Cl) and thus increased this compound.
Conclusion: Based on the results of this study, Zinc oxide nanoparticles can affect the growth and physiological stages of lemongrass and therefore it can be used to increase the production of rosmarinic acid.

Abstract Aim: The aim of this study was the investigation of the effect of chitosan on phenolic compounds, rosmarinic acid content, and  key genes expression involved in the biosynthesis of these compounds in Melissa officinalis L. cell suspension culture.
Material and Methods: A combination of NAA (1mg L^-1), 2, 4-D (1mg L^-1), and kinetin (0.5 mg L^-1) and stem explants were used for callus induction. After initiation of cell suspension culture, chitosan treatment (0, 50, and100 mg L^-1) was performed for one, three, and five days in a factorial experiment based on a completely randomized design with three replications. Phenylalanine ammonia-lyase (PAL) activity, soluble protein, phenolic compound, and rosmarinic acid content were measured. Also, the expressionof phenylalanine ammonia-lyase and rosmarinic acid synthase (RAS) genes was evaluated by real-time PCR.
Results: PAL activity at 50 mg L^-1 chitosan showed the highest increase after three days of treatment, which was accompanied by an increase in phenolic compounds. The relative expression of the PAL gene at 50 mg L^-1 chitosan increased 2.5 fold at three days after treatment compared to control. This increase in the expression of the PAL gene resulted in an increase in enzyme activity. However, the highest increase in expression of the RAS gene was observed at 100 mg L^-1 chitosan in five days after treatment, which led to an increase in rosmarinic acid content.
Conclusion: According to the results, chitosan treatment is recommended to increase of rosmarinic acid content in lemon balm cell culture for five days.
 

Abstract Aim: In this study, sodium nitroprusside effect as a producer of NO on growth, antioxidant enzyme activities and some physiological parameters in in vitro cultured Melissa officinalis seedlings were studied.
Material and methods: After establishment of Melissa officinalis seedling culture, seedlings were treated with different concentrations of sodium nitroprusside (0, 25, 50 and 100 µM). Then, they were harvested for growth, protein content, secondary metabolites, lipid peroxidation level and antioxidant enzymes activities analysis after 10 days.
Results: Results showed that growth and protein content decreased with increasing concentration of sodium nitroprusside. Phenolic compounds amount, total flavonoids and anthocyanins increased by sodium nitroprusside. Also Malondialdehyde content as lipid peroxidation product was significantly increased. In response to oxidative stress, chatalase and peroxidase enzymes activities were respectively increased at 50 and 25 µM sodium nitroprusside while enzymes activities showed decreasing at 100 µM.
 Conclusion: Overall, the results indicate that sodium nitroprusside as NO producer damage the cell membrane. Therefore reduced Melissa officinalis seedling growth and caused oxidative stress in them. To overcome produced free radical, secondary metabolites amounts and antioxidant enzymes activities were increased.