فهرست مطالب d. rasoli

The elicitors are biotic and abiotic compounds that by stimulation of defensive responses causes biosynthesis and accumulation of secondary metabolites. In this research, the expression of KO, UGT85C2, UGT74G1 and UGT76G1 genes involve in production pathway of steviol glycosides in the Stevia rebaudiana were investigated under chitosan, yeast extract and methyl jasmonate as elicitors.
For this purpose, the stevia plants were treated by the elicitors in 3 concentrations of 20, 40 and 80 mg/L and then apical leaves were harvested after one month. The results showed that chitosan in the concentration of 20 (mg/L) significantly increased the expression of UGT85C2 and UGT76G1 genes compared to control plants (16 and 5%). Plus, Chitosan in the concentration of 40mg/l significantly increased the expression of UGT85C2 gene (14%). Methyl jasmonate 20mg/l caused the highest expression of KO gene, which increased by 13% in comparison with control plant. Also, the expression of UGT85C2 gene under the concentration of 20 methyl jasmonate showed a significant increase. According to the results, it was found that increasing the concentrations of chitosan and methyl jasmonate had a negative effect on gene expression profiles of steviol glycosides. Yeast extract in the concentration of 40mg/l significantly increased the expression of UGT85C2 and UGT76G1 genes, which showed 11 and 5% increase in expression, respectively. It was specified that concentration of 40mg/l compared to concentrations of 20 and 80mg/l of yeast extract had a better effect on gene expression enhancement. Hence, according to the results, it can be concluded that chitosan and methyl jasmonate at low concentrations and yeast extract in a moderate concentration can stimulate of the gene expression profiles that involved in the production of steviol glycosides, so increasing the amount of chemical compounds can be effective in the production of secondary metabolites in s. rebaudiana.

New educational strategies are needed in learning the basic issues in nursing education. Developed concept mapping is a strategy to facilitate the thinking, teaching, learning and evaluation. The aim of this study was to compare the effects of education in the form of concept mapping method on learning of health assessment lesson in nursing students.

In an experimental study with two groups, pre-test post-test design, 40 nursing students of the third semester were selected through convenient sampling method, and they were randomly divided into two groups of experiment and control. The pretest students in the experimental group were trained by using concept maps for six sessions of two hours, and the control group received conventional method training for five sessions of two hours. Then, they took the post-test. Data gathering tool was a researcher made test consisted of two parts: The first part included demographic characteristics and, and the second part consisted of forty multiple-choice questions to assess learning on health assessment. The results were analyzed by using binominal test, independent and paired t-tests by SPSS19 software.

The mean and standard deviation of the students’ scores before and after applying the conventional method were (8.4 ±1.57) and (9.05 ±1.71) respectively, whereas it was (8.55±2.31) and (12.15±3.74) in the concept map group, respectively. The study results revealed a significant difference between the pre and post training scores in concept map group (P<0001), and in conventional group (P=0/008). Post training scores in concept map group (12.15±3.74) revealed a significant difference comparing to the conventional group (P=0/001).

Due to the effectiveness of concept mapping teaching methods in learning and performance of the students, it is highly recommended to use this method in order to enhance students'' critical thinking and deep learning.