محسن حسینی

The severe impact of drought and salinity on plant productivity presents a significant threat to worldwide food security. Plants exhibit the capacity to sense stimuli in their environment and adjust defense mechanisms through diverse regulatory networks to cope with abiotic stress. The complexities of drought and salinity tolerances can be deconstructed into contributing factors and mechanisms, classified under two categories: genetics and epigenetics. Epigenetic mechanisms play a role in partially attributing crop adaptation to the most formidable drought and salinity stresses. Plants respond to stress in part by undergoing stable alterations in gene expression, a process that involves the physical "marking" of DNA or its associated proteins, commonly called epigenetics. Plants utilize various epigenetic mechanisms to refine gene expression, vital for adaptation and phenotypic plasticity. These include DNA methylation, histone modifications, chromatin remodeling, epitranscriptomics, and gene silencing mediated by small RNAs. Notably, epigenetic modifications can be inherited or erased. Enhanced knowledge of epigenetics complements genetics and will aid in developing strategies to integrate them into crop improvement programs aimed at addressing adaptation to abiotic stress. This review highlights the latest and noteworthy findings regarding crop epigenetic responses to abiotic stress signals, particularly those pertinent to drought and salinity tolerance.

Low temperature (LT) is one of the most important factors that limits growth, distribution and production in cereals. The purpose of the present study was to identify some traits related to LT tolerance in different phenological development stages in lines resulted from crosses between Pishtaz and Norstar wheat. Under experimental conditions, LT tolerance, shoot apex developmental, final leaf number (FLN), activity of antioxidant enzymes, total sugars and H2O2 contents were investigated. Results of double ridges formation and FLN showed that winter and facultative habit genotypes spent the longer time in the vegetative phase and entered the reproductive phase with delay. These genotypes also were more tolerant to LT in comparison to spring habit genotypes. Analysis of variance showed that genotypes, sampling period, and their interaction were highly significant for most of the traits. Ascorbate peroxidase (APX), guaiacol peroxidase (GPX), polyphenol oxidase (PPO), catalase (CAT), superoxide dismutase (SOD), and total sugars content reached their maximum in all genotypes at the second period of LT acclimation but higher in winter and facultative than spring habit genotypes.

Low temperature stress is a kind of abiotic stress directly affecting growth and productivity of important agricultural products including wheat, worldwide. The purpose of the present study was to investigate the relationship between developmental regulation with low temperature tolerance, hydrogen peroxide (H2O2) accumulation and the expression of antioxidant enzymes genes in different phenological development stages in lines (RIL) of crosses between Pishtaz and Norstar wheat. Winter- and facultative-habit genotypes in the second period of low temperature acclimation, coinciding with the saturation range of the vernalization requirement, reached their maximum of low temperature tolerance, followed by a decrease in low temperature tolerance at the reproductive phase in third period of low temperature acclimation. Spring genotypes had very limited low temperature tolerance. Relative expression of TaVRT-1 gene in spring genotypes showed high and constitutively expression during low temperature acclimation periods. However, the relative expression of this gene in winter- and facultative-habit genotypes is expressed only after vernalization saturation. The relative expression of antioxidant enzymes genes were higher in winter- and facultative-habit genotypes than spring- habit genotypes, and reached its maximum in the second period of low temperature acclimation. Along with the increasing of relative expression of TaVRT-1 gene and decreasing antioxidant enzymes genes in the third period of cold acclimation, the accumulation of H2O2 reached maximum. Our results suggested that winter- and facultative-habit genotypes decreased the expression of TaVRT-1 gene and subsequently increased the length of the vegetative phase and the relative expression of antioxidant enzymes genes. Such reactions prevented the oxidative damage induced by low temperature stress and promoted more tolerant of low temperature.

Culture is regarded as a part of English language teaching (ELT). Also, ELT textbooks are a main source of intercultural teaching / learning in most English as a Foreign Language (EFL) learning contexts. Thus, representation of cultural content and development of (inter)cultural aspects are important issues in ELT textbooks, particularly in EFL contexts. This study analyzed the representation of culture in the Vision series, a recently developed ELT series used nationwide in Iranian high schools, and examined how multimodality in these local textbooks would provide context to develop (inter)cultural aspects. To collect the data, an adapted version of Cortazzi and Jin’s (1999) classification of culture (source, target, international, and globally-shared) was used to analyze the content of the Vision series to see which culture was reflected in these high school textbooks. Additionally, the Wenninger and Kiss’s (2013) semiotic framework was used to examine how multimodality would serve cultural contents through analyzing image-text relationship. The content analysis demonstrated the domination of source (i.e., Iranian) and globally-shared cultural elements with less attention to the target and international cultures. Furthermore, the results showed that multimodality in these textbooks could provide the opportunity for critical cultural reflection, though it was limited to source and globally-shared cultures. By implication, ELT material developers in Iran should incorporate more appropriate materials and culturally engaging visuals associated with diverse cultures into local ELT textbooks to promote Iranian EFL students’ cultural reflection, and, subsequently, their intercultural competence.

Aspartame is a non-nutritive and artificial sweetener which is widely used in diet and low calorie products and also in a variety of foods, drugs and hygiene products. The present study has been conducted in order to evaluation of the effects of aspartame on ovaries in female mice.

In this experimental study, 36 adult female mice were randomly divided into four groups of nine each. For three groups aspartame was administered orally with the doses of 40, 80 and 160 mg/kg.BW respectively, and one group as the control group received normal saline for 91 days by gavage. Also a control group was considered. 24 hours after the last treatment, ovarian tissue and blood samples were collected and used for biochemical, histomorphological, histomorphometric, histochemical and gene expression studies. The obtained data were analyzed using One-Way Analysis of Variance (ANOVA) and Tukey’s test at the significance level of P<0.05.

In ovarian histomorphometric studies, aspartame at a dose of 160 mg/kg significantly reduced growing follicles and significantly increased atresia follicles. Also in biochemical studies caused a significant decrease in TAC and a significant increase in MDA compared to control group. In connection with the studied genes, aspartame at a dose of 160 mg/kg caused a significant decrease in the expression of Bcl-2 gene and also a significant increase in the expression of P53 and Caspase-3 genes compared to the control group.

It seems that high dose aspartame can cause adverse effects on histomorphology, histomorphometry and expression of P53, Bcl-2 and Caspase-3 genes in rat ovaries