Résumé
Introduction: Chitosan is one of the polysaccharides containing nitrogen which is synthesized naturally by deacetylation reaction of chitin and is confirmed as one of the efficient biostimulants for improvement of secondary metabolites production in medicinal plants
Objective: to evaluate the effect of different concentrations of chitosan biostimulant on vegetative biomass traits and secondary metabolites of Stevia plant
Methods: the experiment was conducted in a randomized complete block design with three replications in greenhouse conditions. The treatments were spraying of chitosan in four levels [0.05, 0.1 and 0.2 percent] and control treatment [spraying with distilled water]
Results: in this study, the obtained results of variance analysis showed that spraying of chitosan had significant effect on leaf dry weight, shoot dry weight, leaf length [P <0.05], phenols and rebaudiosides A [P <0.01]. In this experiment, the highest fresh and dry weight of stems, leaves and shoots were observed at 0.1% Chitosan in a way that by increasing the chitosan concentration from 0.1 to 0.2 % the decreasing trend occurred. The highest amount of phenol was recorded at 0.1% concentration. Also, chitosan at 0.2% concentration had the maximum impact on rebaudiosides A
Conclusion: Chitosan spraying improved vegetative biomass traits and biochemical parameters such as rebaudiosides A in stevia plant
Résumé
We are reporting a series of 19 patients with 20 nodular basal cell epitheliomas removed by elliptical surgical excision. Histologic examination of the specimens by serial sections in each case revealed a central nodular growth surrounded by a number of small nests of basalioma cells in connection with the lower surface of the epidermis and the infundibular portion of the pilosebaceous structures. The superficial nests extended as far as 5.5 mm distant from the central nodule. The nodular lesion was completely excised in all cases. However, the peripheral nests extended to the line of excision in 13 of the 20 specimens requiring re-excision of the area. The re-excisional specimens were positive for residual superficial nests in six of the 13 cases