In the present study, the effect of swim stress on morphine-induced TOLERANCE was investigated in mice using formalin test. In this respect, intraperitoneal administration of different doses of morphine (3, 6, and 9 mg/kg) induced a dose-dependent antinociception in both acute and chronic phases of the formalin test. In addition, an exposure to swim stress 2 or 3 times for 3 consecutive days was performed in order to induce TOLERANCE. This exercise decreased morphine-induced antinociception. Meanwhile, morphine administration (25 mg/kg) for 3 days in the presence of swim stress (for two to three times) potentiated TOLERANCE induced by morphine in both phases of the formalin test. Administration of a higher dose of morphine (50 mg/kg) for 3 days in the presence of swim stress did not alter morphine-induced TOLERANCE in both phases of the test. On the other hand, administration of the latter dose of morphine for 3 days in the absence of swim stress decreased morphine-induced antinociception in both phases of the formalin test. It can be concluded that there may be a cross interaction between morphineinduced antinociception and swim stress.

In order to investigate of fifteen wheat genotypes with winter, spring and facultative growth types to COLD stress, two field and laboratory experiments were organized in Agricultural Research Center of West Azerbaijan Province in 2007-8. Arranging of laboratory and field experiments were Completely Randomized Design with five replications and Randomized Complete Blocks Design with three replications at three different planting dates, respectively. Results of laboratory analysis showed that differences between genotypes on ion leakage, potassium accumulation and total dry matter were significant. The most and less potassium accumulations were allocated for C-81-14 and Sayson genotypes, respectively. M-81-13 and Zarrin genotypes had the highest and lowest levels of ion leakage. Within cultivars Gaskojen had more total dry matter and Zarrin, Kavir, M-81-13 had the low values. At six leaves step, spike was observed for spring types, but at winter and facultative types there was no apex. Combined analysis of variance for field experiment demonstrated that between three sowing dates, cultivars and interactions of c×d for traits of plant height, spike per square meter, 1000-kernel weight, and grain yield, total dry matter was significant. Having negative correlation of ion leakage with total dry matter and grain yield could be used an indirect criterion for screening of tolerant genotypes. Resistant genotypes to COLD stress became Alvand, Tus, C-82-12, M-79-7, Zarrin, Kavir, Mahdavi, and Gaskojen.

In order to study the response of 120 genotypes of rapeseed (including 100 hybrids and 20 parents) in terms of COLD stress TOLERANCE, an experiment was conducted in α-lattice design with two replications under normal (September) and late sowing (October) conditions during two years. Combined analysis of variance showed that genotypes were significantly different at 1% and there was a significant genetic variation among the studied genotypes. In addition, there was a significant difference between the environments (normal and late sowing) at 1% in both years and the effect of late sowing on the yield of rapeseed was different from that of normal sowing. Total mean of seed yield in non-stressed condition was 4. 9 ton/ha and in COLD stress condition was 2. 72 t/ha (34% reduction compared to normal sowing conditions). Principal component analysis (PCA) using six indices of COLD stress TOLERANCE (MP, GMP, HARM, TOL, SSI and STI) showed that the first two components justify about 99. 85% of the variation in the population. The biplot of first and second components divided the genotypes into four different groups and identified 29 high yielding and COLD tolerant genotypes. Similarly, cluster analysis divided the genotypes into four different groups and grouping of genotypes using cluster analysis showed good agreement with the results of principal component analysis. Correlation between different indices of stress TOLERANCE and yield in stress (YP) and non-stress (YS) condition showed that TOL and SSI had positive correlation with YP and negative correlation with YS. Furthermore, the four indices of MP, GMP, HARM and STI showed positive and significant correlation with yield in both stressed and non-stress conditions. The results of this study showed that the STI index has a high efficiency in selection of rapeseed genotypes for COLD TOLERANCE and can be successfully applied in breeding programs.

Introduction Temperature influences plant physiological processes, cellular structure and development. Habitat from which plants originate has undeniable effects on plant TOLERANCE to COLD temperatures. Plants from higher latitudes exhibit more TOLERANCE to COLD stress than plants from lower latitudes. When plants are exposed to COLD stress, a sequence of events is triggered inside them, leading to an improved TOLERANCE to the environmental condition. This phenomenon is known as plant hardening. Having access to winter-hardened species and cultivars is one of the important necessities for the development of crop production systems in local microclimates of COLD regions. Utilizing genetic diversity in crop plant resources is an important approach towards achieving sustainable agriculture. Diversity in Iran`s forage germplasm for traits such as early maturity, high ratio of leaf to stem, dense ground cover and high yield has been shown in temperate regions such as Karaj and Mashhad (Abbasi, 2009, Abbasi et al., 2017). Testing a selection of these germplasm accessions can determine their potential for growing under water-limited conditions in COLD regions. Hence, different genera and species of legumes in national plant gene bank of Iran originated from high latitudes were used to be evaluated under COLD growing conditions. Materials and Methods A total of 124 annual-forage accessions from 40 species and 10 genera were selected based on the previous research works and were planted in an experimental filed at Jolge-Rokh agricultural research station. The number of accessions in each genus included Trifolium (36 accessions), annual medics (28 accessions), Onobrychis (9 accessions), Vicia (21 accessions), Melilotus (17 accessions), Lolium (6 accessions), Bromus (5 accessions), and Phalaris (1 accession), Lathyrus (1 accession) and barley (1 accession). Each accession was planted in two 2-meter long rows spaced 50 cm apart using an augmented experimental design. Some of the traits characterized in this study from autumn to spring included growth rate in spring and autumn, COLD-TOLERANCE score, plant height etc (IPIGRI, 1984). Statistical descriptive parameters were determined for the evaluated traits. One-way ANOVA (analysis of variance) and Duncan's multiple tests were performed on data of each trait. The analyses were carried out by SPSS 15. Results and Discussion Meteorological data showed that there were a total of 68 days of freezing temperatures in the region from November till March. The lowest absolute temperature recorded was-17. 4 ° C in December. Also, the mean of daily minimum temperature for December, January, February and March was below zero and the mean of daily maximum temperature for December, January and February was-10 ° C, indicating the occurrence of COLD stress in the region. The results of one-way ANOVA analysis for the investigated genera and species showed that there were significant differences among their traits at 1 % probability level, particularly prior to COLD stress. Lolium and Bromus were the most tolerant species among the narrow-leaved forages and the tested germplasm. Among forage legumes, sweet clover exhibited the highest TOLERANCE to COLD temperatures. Although the species vicia, Lathyrus and Iranian clover were not tolerant to COLD, they were found to be beneficial in terms of soil conservation and sustainability due to the production of proper vegetative cover prior to the COLD spell, which lasted till the spring of the next year. Based on the results of this investigation, the studied species and genera can be classified into the following groups: 1-COLD-tolerant forage grasses including accessions of Lolium: 14TN00072, 14TN00038, 14TN00052, 14TN00054 and accessions of Bromus: 10TN00049, 10TN00012, 10TN00036, 10TN00039, and 10TN00026. 2-COLD-susceptible forage grasses such as accessions: KC126013 (L. temelentum) and barley. Although this group was sensitive to COLD, they produced good vegetative cover on ground before the occurrence of COLD, which can be used as mulch for soil protection throughout the year. 3-COLD-tolerant legumes, such as accessions of Melilotus: 58TN00025, 58TN00047, MahNo313, 58TN00182, 58TN00223, 58TN00140, 58TN00181, 58TN00080, and 58TN00190 4-COLD-susceptible forage legumes: they were categorized into two groups, one group produced good vegetative cover on ground before the COLD spell such as accessions 44TN00047, 44TN00041, and 44TN00005, and the other group failed to produce enough vegetative cover on ground such as some accessions of annual medics, Onobrychis, and Trifolium.

Phenological, molecular and metabolite analysis during vernalization in wheat show that there is a tight relationship between vernalizatio fulfillment/reproductive transition with decrease in the accumulation of some metabolites and expression of COLD-induced genes/proteins. In the present review, we will describe a number of similar protective metabolites and COLD related proteins which are present or expressed in both sensitive and tolerant wheat genotypes. Based on several studies duration of COLD acclimation in winter genotypes is quite higher which is influenced by developmental genes and consequently the level and duration of expression of COLD-lnduced proteins is longer when compared with spring genotypes. Also, the initial rate of COLD acclimation in COLD tolerant winter wheat is higher than the COLD sensitive genotypes. Our results show that the expression patterns of COLD related proteins and metabolites are consistent with the trend of the developmental factors that have regulatory effects on proteome/metabolome. In addition, sub-zero acclimation of plants in field conditions during autumn/winter seasons has significant effects on numbers, levels and patterns of COLD associated proteins in compared with plants acclimated in controlled condition at low temperature but above zero temperature. This present work, provide a novel insight to uncover the molecular mechanisms behind COLD adaptation in wheat and pave the way to breed wheat for COLD TOLERANCE.

Insects can increase their survival at subzero temperatures, prior to long or short term exposure, to non-lethal COLD temperatures by COLD acclimation (ACC) or rapid COLD hardiness (RCH). In this research, the effect of rapid or gradual decrease in temperature on COLD TOLERANCE of adults of the greenbug, Schizaphis graminum (Rondani) was investigated. LT50 (lower lethal temperature for 50% mortality) of aphids acclimated at 10°C for one week showed no significant differences with control (aphids reared at 20°C). In addition to the COLD acclimation, adults of S. graminum showed RCH response too. When the rearing aphids at 20°C were transferred directly to a range of sub-zero temperatures for 2 h, LT80 (lower lethal temperature for 80% mortality) was -11.6 °C, but acclimation at 0°C for 5 h before transfer to -11.6 °C, induced maximum RCH, led to increase of survival to 73%. RCH was induced by cooling of the insects at 0°C for different rates. Maximum survival (66%) was achieved by cooling at 0.05°C/min. Accumulation of sugars and polyols is one of the major mechanisms underlying ACC and RCH. In this study, trehalose and glucose increased considerably through ACC and RCH treatments, suggesting the role of these compounds in increasing COLD TOLERANCE of S. graminum.

Chickpea (Cicer arietinum) is one of the most important legumes, classified as a COLD-sensitive species, and each year, the sudden drop in temperature leads to a significant loss of chickpea yield. miRNAs are highly conserved small noncoding RNAs that regulate expression of their target genes by degradation of their mRNAs or suppressing their translation, and their roles have been proved in COLD stress response in various plants. In the current study, in order to identify COLD stress responsive miRNAs in chickpeas, following transcriptome sequencing of a COLD stress tolerant cultivar (Saral) and a COLD stress sensitive line (ILC533) in response to COLD stress, the sequences of the COLD responsive genes were analyzed by c-mii software to identify possible miRNAs. Then, the target genes of a number of important miRNAs were identified using psRNA target software. The results showed that 30 and 20 miRNAs responded to COLD stress in the tolerant and sensitive genotypes, respectively. Through comparative analysis of COLD responsive miRNAs in the contrasting genotypes, miR319, miR393, miR394 and miR159 were demonstrated as candidate miRNAs involved in COLD TOLERANCE and their roles was further inspected. It is hoped that the obtained results will be useful for development of COLD tolerant chickpea cultivars.