فصلنامه زیست شناسی تکوینی
سال چهاردهم شماره 2 (پیاپی 54، بهار 1401)

Irrigation water salinity is one of the growing problems in the path of agricultural and horticultural production that researchers must determine different solutions to this problem and provide it to farmers. In this regard, silicon and selenium due to their positive role, both structurally and as cofactors of enzymes related to the metabolism of various antioxidants can play an effective role in increasing plant tolerance to salinity stress. For this purpose, a factorial experiment was conducted in a completely randomized design including four salinity levels and three fertilizer sources of silicon and selenium compounds in normal and nano size in Shirvan Faculty of Agriculture, Bojnourd University. Statistical analysis showed that the main effect of salinity stress, as expected, had a significant reducing effects on all studied traits (except essential oil). In these variables, although the main effect of fertilizer type was not statistically significant, but at different levels of silicon and selenium consumption, an increasing trend of these variables was observed, indicating the positive effect of simultaneous use of these two elements in reducing the effect of salinity. Also the main effects of salinity and fertilizer sources on leaf length and width factors, fresh and dry weight of stem, number of sub-branches, number of leaves and leaf area index were significant. In all these indicators, the application of silicon and selenium elements in nano size has always been more effective than the normal size of these elements, which should be considered as a management strategy in salinity stress conditions.

Pre-sex selection is the process by which Y or X-bearing spermatozoa are used to produce the desired sex in the offspring. X-bearing spermatozoa are believed to have a longer lifespan, and are more resistant to acidic conditions, temperature changes, and even oxidative stress compared to Y-bearing.

The present study was aimed to investigate the effect of heat stress on sperm parameters and sex ratio of sperm containing X or Y chromosome after freezing-thawing of goat semen. The diluted semen of the heat stress group was first placed at 43 ° C for 30 minutes and then frozen-thawed as in the control group.

The results showed that heat stress led to a significant reduction in the overall sperm motility, viability and sperm cell membrane integrity compared to the control group. Also, in the heat stress group, the mean Y to X ratio was 94.4%, which showed a significant difference (p <001) compared to the expected Y to X ratio of 1.

Applying heat stress to sperm in vitro can lead to a significant reduction in sperm parameters. In addition, the decrease in the number of Y-bearing spermatozoa in the survived population post thawing, may indicate that the Y-bearing spermatozoa are more sensitive and fragile compared to X-bearing spermatozoa in goat species. Keywords: Sex determination, Cryopreservation, Heat stress, Goat sperm

The genus Rubus L. belongs to the genus Rosaceae. This genus includes more than 750 species in the world. Among some species of this genus such as R. dolichocarpus Juz. And R. ochthodes Juz. Morphological similarity is observed in traits such as the number of leaflets, the shape of the earrings and the color and shape of the petals, which makes it difficult to identify these two closely related species. The species R. dolichocarpus in the flora of Iran is declared synonymous with the species R. ochthodes, while these two species in the flora of Iranica, the flora of Russia and the flora of Iran are two separate species in one subgenus and two different segments. For this purpose, in this study, the taxonomic relationships of these two species based on morphological characteristics were investigated. The results indicate differences in morphological traits such as the shape and condition of the annual stem, the shape of lateral leaflets in the flowering stem, the shape of the leaflets. And the density of flowers in the inflorescence. Also, according to molecular data using the ITS nuclear marker, these two species have 36 different nucleotides, which confirms the separation of the two species. Therefore, according to the results obtained in this study and comparison with previous studies, it is suggested that two species of R. dolichocarpus and R. ochthodes. According to the flora of Iranica, the flora of Russia and the flora of Iran should be defined as two separate species.

Carduus L. species (belong to Asteraceae Bercht. and J. Pres) replace endemic plant species by forming dense colonies and can compete with native vegetation for light, nutrition, and moisture. In order to obtain more information about this invasive genus, the chromosomal number of Carduus pycnocephalus L. were investigated from Hamedan and Kermanshah provinces in the west of Iran. 14 special stations were selected of some parts of these provinces. Chromosomal counting was done in the metaphase stage of the root meristems by seed germination and by using the standard squash method. Results showed that chromosomal number in these studied taxa was 2n=2x=34 in 14 populations gathered in this research. By comparing the chromosome number found in this study with previous research, this chromosome number is belonging to C. pycnocephalus subsp. arabicus (Jacq. ex Murray) Nyman. Therefore, the diploid chromosome number in the taxa of this species can be taxonomical value.

In recent years, our country has drawn an increasing amount of attention to medicinal plants. Because different plant species Savory inappropriate harvesting of natural areas by humans, and the growing threat of biotic and abiotic stresses following the work resulted in reduced genetic diversity of a species is, a species of genetically keep reserves Curb upper's. Seed storage techniques at very low temperature (-196 °C) using liquid nitrogen is one way of maintaining germplasm with much less cost and without loss of viability on storage and it is useful when it does not lead to changes in the chemical composition of essential oil in the desired plant. In order to investigate the phytochemical stability and compare the type and amount of identified compositions, the treated seeds were transferred to the liquid nitrogen at –196°C for 1 week as compared to the control. The aerial tissues of in vitro-grown plants were collected and dried in the laboratory. The essential oil was isolated by hydrodistillation and analyzed by a combination of capillary GC and GC-MS. Twelve compounds were recognized in the essential oil of mentioned plant in the cryopreservation. Results indicated that regarding the number, type and percentage of compounds existing in the essential oils, there was no difference between the control and cryopreservation treatment so by using the cryopreservation technique, the seeds of this valuable endangered species can be preserved for a long period.

Strawberry fruit (Fragaria ananasa) has many uses in the food industry, especially the essential oil and extract obtained from this fruit is used in many food products. In this study, changes in qualitative and chemical traits of two strawberry cultivars during 15 days of storage at 4 ° C were investigated. The results showed that the firmness of texture, the amount of soluble solids and the taste index in Kamaroza cultivar were significantly higher than Parus cultivar. The pH of both cultivars increased, while during these 15 days the amount of soluble solids and taste index in Parus cultivar increased significantly. Tissue stiffness and weight loss percentage in both cultivars showed a significant decrease during 15 days, but this decrease was more in Kamaroza cultivar. The studied qualitative and chemical traits as well as taste index in two strawberry cultivars were effectively changed during 15 days under the influence of cultivar type and storage period. These studies showed that the type of strawberry cultivar is a determining factor in terms of nutritional value and the content of natural compounds during storage and post-harvest conditions, so that Camarosa cultivar showed a special advantage over Parus cultivar in these respects. Low temperature storage seems to be an efficient way to preserve strawberry fruit.

Echinacea purpurea L. is very important in the pharmaceutical industry due to its valuable secondary metabolites. In this experiment, the investigation of salicylic acid in tissue culture medium on callus and adventitious root secondary metabolites of Echinacea was conducted. The best treatment for callus production was MS medium contain 0.5 mg/l BA and 1 mg/l 2,4-D. The best treatment for adventitious root was obtained in 1/2 MS medium contain 0.5 mg/l IBA in dark condition. Salicylic acid at concentrations of 0, 50, 100 and 200 mg/l in liquid MS medium, and then fresh weight, phenol content, flavonoids and antioxidant activities were measured. The highest antioxidant activity was observed in 100 and 200 mg/l of salicylic acid in callus and adventitious root respectively. Salicylic acid promoted phenol and flavonoid content rather than control medium (without hormone). The highest gallic acid content with 2.11 mg/g root fresh weight was recorded in 100 mg/l 3 days after inoculation. Also the best medium for cafeic acid content was observed in 200 mg/g root fresh weight 5 days after inoculation.