alameh babajani

This study was performed to identify the anatomical responses of lemon balm to zinc oxide nanoparticles (nZnO) at the concentrations of 100 and 300 mg/l. The microscopic observation showed that the nZnO300 had the largest diameter of the central cylinder and the diameter of xylem and phloem in the root compared to the control. The study of stem cross-section revealed that the highest stem diameter was observed in response to the nZnO100 group. The maximum thickness of collenchyma and the highest diameter of the central cylinder and the diameter of phloem and xylem were also recorded in the nZnO100 group. Comparing the leaf cross sections indicated that the thickness of the upper and lower epidermis, the diameter of the xylem, the thickness of the spongy parenchyma in the nZnO100 group were significantly increased relative to the control. Comparison of petiole cross sections showed that the thickness of the upper and lower epidermis and the diameter of the central/lateral phloem and xylem in all nZnO-treated seedlings were significantly reduced compared to the control. This study provided anatomical evidence that indicates fundamental changes in the fate of cell differentiation and tissue formation in response to nZnO. Future research is needed to link physiological, molecular, and anatomical evidence to accurately understand the impact of nanoproducts on the entire life of plants, especially crops and medicines.

The aim of this study was to investigate the effect of application of selenium nanoparticles on anatomy and pattern of tissue differentiation in lemon balm. Plants were treated with nano-selenium (nSe; 0, 10 and 50 mg/l) and bulk selenium (BSe). The results of this study indicated that nanoselenium had a positive and beneficial effect at a concentration of 10, but a concentration of 50 induced toxicity. The microscopic assessment of stem cross sections showed that the diameter of the central cylinder was increased compared to the control. The highest increase was related to the seedlings exposed to the 50 and 10 mg/l. Stem thickness and diameter in the nSe-treated seedlings at 50 mg/l and bulk 10 mg/l were increased compared to the control. Xylem diameter decreased in response to the supplements, the lowest belongs to the nSe50. Monitoring the leaf cross sections showed that nSe10 increased thickness of xylem diameter, palisade and sponge parenchyma compared to the control. Comparison of petiole cross-sections indicated that the thickness of the epidermis and the diameter of the central the central and lateral xylem were changed. While, 50 mg/l nSe declined these traits. Therefore, the results of this study indicate that the application of applied concentration-dependent selenium, in addition to inducing physiological and molecular changes, causes anatomical changes and tissue differentiation. Further research is needed in the future to determine the mechanism of these responses.

This study investigated the molecular and physiological responses of lemon balm seedlings to the manipulation of nutrient solution with zinc oxide nanoparticle (nZnO) at 0, 100, and 300 mgl-1. The augmentation in biomass accumulation and photosynthetic pigments resulted from the nZnO utilization. The exposure of seedlings to nZnO modifed both primary and secondary metabolism in leaves. The nanosupplements upreguated activities of phenylalanine ammonia lyase and catalase enzymes. Moreover, the incease in concentrations of proline, flavonids, and glutathione resulted from the application of nZnO. Furthermore, the nZnO treatments up-regulated the transcription of phenylalanine ammonia-lyase (PAL) and Coumarate: CoA-ligase (4CL) genes, two genes responsible for the production of secondary metabolites. These comparative physiological and molecular investiagtions on plant responses to nZnO and its bulk type may serve as a theoretical basis for function in agricultural and medicinal industries.