نشریه علوم و تحقیقات بذر ایران
سال هشتم شماره 1 (بهار 1400)

One of the major problems in arid and semi-arid conditions is the lack of irrigation water, and soil and water salinity. In order to investigate the effect of salinity and drought stress on the quantitative and qualitative germination characteristics of portulaca, malva and amaranthus, a study done as factorial in a completely randomized design with three replications in the research laboratory of the Faculty of Agriculture in 2016. In the first experiment first factor was effect of salt stress including NaCl was the effect of osmotic potential level (0, -6 and -12 bar) and the Second factor three weeds spicefic (Portulaca, Malva and Amaranthus). In the second experiment first factor was effect of drought stress including PEG 6000 was the effect of osmotic potential level (0, -3 and -6 bar) and the Second factor three weeds spicefic (Portulaca, Malva and Amaranthus). The results showed that all the studied traits except the germination percentage in cheese plant were affected by the interaction effects of salinity and drought stress. Salinity and drought stress reduced most of the studied traits in each plant. In non-stress conditions, portulaca and amaranthus had the highest percentage of germination and seedling germination vigor, however, increasing the activity of catalase, peroxidase and protein concentrations in cheese plant, especially in salinity stress -6 times and drought-3 times, indicated a higher resistance of this plant than the other two species. In the case of portulaca and amaranthus, salinity and drought stress reduced seed germination, which seems to reduce germination due to reduced water availability or interference with some aspects of metabolism, such as altering the balance of growth regulators.

Seeds of crops deteriorate during storage. The main aim of this study was to investigate the effect of selenium on the improvement of deteriorated seeds in two lentil cultivars. The research was conducted as a factorial experiment based on a completely randomized design. The seeds of two lentil cultivars (Kimia and Bilehsavar) were exposed to different deterioration conditions (no deterioration, mild and severe deterioration). Then, these deteriorated seeds were primed by different concentrations of selenium (0, 250, 500 and 750 µM). After the priming, the seeds were evaluated in a standard germination test and related traits were measured. In non-deteriorated seeds, priming with selenium did not have significant effects on the seed germination and seedling vigor characteristics. Under mild and severe deterioration conditions, seed priming with selenium at 0, 250, and 500 μM had not significant differences in most seed and seedling vigor characteristics, but priming at 750 μM improved this traits. For example, under mild and severe seed deterioration conditions, seed priming at 750 μM selenium increased the germination rate by 30 and 62 %, respectively, and decreased the mean germination time by 13 and 17 %, respectively. In terms of the activity of catalase, peroxidase and superoxide dismutase enzymes, it was found that in non-deteriorated seeds, the activity of these enzymes were increased 81, 19 and 43% respectively; by seed priming with selenium 750 μM. The effect of seed priming at 750 μM selenium on activity of these three enzymes was 221, 92 and 86% for mild seed deterioration and 376, 143 and 141% for severe seed deterioration conditions, respectively. Also, the effect of seed priming with selenium on the studied traits was similar for the two lentil cultivars Kimia and Bilehsavar. Therefore, it seems that seed priming with selenium 750 μM had the ability of improvement the deteriorated lentil seeds Kimia and Bilehsavar.

Wheat is the most important agricultural product in the world and plays an important role in ensuring human food security. According to the fact that Wheat is planted after Quinoa, it is feared that the presence of Quinoa in Wheat cultivation may cause negative allelopathic effects. To investigate the effect of aqueous extract of Quinoa on seed germination and early growth of Wheat seedling, a factorial experiment based on completely randomized design with four replications was conducted at Seed Technology Laboratory of Shahed University of Agriculture, Tehran, Iran. Experimental factors included organ type (inflorescence, leaf, stem and root) and aqueous extract concentration of Quinoa (0, 5, 25, 50, 75 and 100%). In this experiment traits such as germination percentage, shoot length, root length, plantlet length, plantlet dry weight, relative water content, alpha-amylase activity, soluble sugar content, total phenol and proline of Wheat seedling were studied. The results showed that low concentrations of the extract of Quinoa (5 and 25%) had not only negative effects on germination percentage, plantlet length, dry weight and relative water content of Wheat, but even improved these traits. High concentrations of the extract had negative effects on morphological traits. The negative effects of leaf and inflorescence extracts were more than the effects of stem and root extracts. Application of different extracts of Quinoa reduced the activity of alpha-amylase and increased soluble sugar, total phenol and amino acid proline in wheat plantlet.

In order to study the effect of priming and irrigation with beeswax waste and licorice extracts on germination, morphological and biochemical characteristics of sesame in drought stress condition, an experiment was conducted as factorial arrangement based on completely randomized design with four replications. The experimental treatments were drought stress (0, -2, -4 and -8 bar), priming (priming with water, beeswax waste extract at 2000 ppm and licorice extract at 5000 ppm) and irrigation with the extracts (water, beeswax waste extract at 2000 ppm and licorice extract at 5000 ppm). The results showed that the priming with beeswax waste extract caused to increase in percentage and speed of germination, seedling dry matter, radicle and plumule length, and CAT and APX activitie in drought stress condition, but MDA and proline contents were significantly decreased by that. Interaction of drought and irrigation showed that in drought stress condition, irrigation with beeswax and licorice extract led to increasing CAT and APX activities that consequently resulted to increasing seedling dry matter and radicle and plumule length. Interaction of priming and irrigation showed that the highest values of seedling dry matter (21.53 mg), radicle length (54.53 mm), plumule length (9.33 mm), CAT (0.377 unit mg-1 protein) and APX (0.557 unit mg-1 protein) activities was assigned to interaction of priming with beeswax waste extract × irrigation with licorice extract. Therefore, it seems that the most appropriate treatment for alleviating the negative effects of drought stress on sesame is pre-treatment with beeswax waste extract and irrigation with licorice extract.

The present study was conducted to reduce the effects of salinity stress on germination and initial growth stages of Thymus vulgaris as a medicinal plant using brassinosteroid (BR) under in vitro culture. Thyme seeds were exposed to different concentrations of salinity (0, 50, 100 and 200 mM) and BR (0.5, 1 and 3 µM), and then different germination and growth indices as well as some phytochemical properties of seedlings were measured. Results indicated that under salinity conditions, the highest germination percentage (95%) was observed at the lowest salt concentration (50 mM) and the highest BR concentration (3 µM). Applying differentBR concentrations improved root and shoot height.It also increased dry and fresh biomass of thyme seedlings in a way that at the same salinity conditions of 200 mM, root and stem length increased about 30.5% and 42.9%, respectively, in samples treated with 3 µM BR in coparison with the ones treated with 0.5 µM BR. The amount of proline and antioxidant enzymes, peroxidase (POD) and superoxide dismutase (SOD) significantly increased in the seedlings treated with the highest BR concentration in comparison with those treated with the lower concentrations, and the seedlings had lower membrane permeability (lipid peroxidation). The results of correlation coefficient showed that there was a negative correlation between cell membrane permeability (amount of malondialdehyde) and all measured biochemical and morphological traits related to seedling growth. According to the results of this study, it is suggested to apply BR during the sensitive stage of seed germination and early growth of garden thyme seedlings under water or soil salinity conditions.

Yew (Taxus baccata L.) has diterpenoid compounds with anti-cancer effects therefore it is one of the most well-known medicinal plants that is in danger of extinction. In this study, which was conducted at the Research Institute of Medicinal Plants of Shahid Beheshti University, the effect of culture medium (MS, 1/2MS and NN), phenolic absorbents (PVP and activated charcoal) and plant growth regulators (IBA, GA3 and BA) was investigated in a factorial design with three replications, with the aim of improving germination and growth of seedlings in in vitro culture. In the following, taxane production was measured in plantlets that were grown in select medium for ten months. According to our results, NN culture medium due to lower concentration of basal salts had no significant effect on germination percentage but increased root length and normal seedling growth percentage. Also supplementing the media with phenolic absorbent extended root length and shoot height as well as increasing normal seedling growth rate. In using PGRs, the highest normal seedling growth rate, shoot height and root length was obtained respectively from IBA × GA3 (0.2 mg/l gibberellic acid × 0.01 mg/l indole butyric acid), IBA × BA (0.2 mg/l gibberellic acid × 2 mg/l benzyl adenine) and 0.1 mg/l indole butyric acid, while PGRs had no significant differences in germination rate. Also, the amount of taxan in the aerial part was higher than the root and the highest taxan in the aerial part was 10-deacetylbaccatinIII  and in the root were taxol and 10-deacetyltaxol, the maximum of all was achieved at the end of the experiment. Overall, the results indicate the positive effect of activated charcoal, PGRs and reducing culture medium macronutrients on root length, shoot height and the normal growth process of Taxus baccata seedling, in order to increase the yeild of yew propagation under in vitro culture condition. The cell culture obtained from the aerial part is much better than the hairy root cell culture.

In order to study effect of seed priming and transplantation on quantitative and qualitative characteristics of sugar beet, an experiment was conducted on a farm land in Naghadeh-Western Azerbaijan at 2018 growing season. The experiment design was split plot based on randomized complete block with four replications. Type of planting method (direct and transplant system) assigned to main plots, and priming (salicylic acid, gibberellic acid, hydroperiming and control (non-priming) assigned to sub plots. The results showed that the effect of planting system was significant on the amount of root sodium, alkalinity, sugar content, coefficient of sugar extraction, shoot dry weight, white sugar yield and molasses sugar content. The effect of priming on all studied traits was significant. Interaction of two treatments was also significant on root potassium, sugar content, white sugar content, sugar extraction coefficient, shoot dry weight, root yield, white sugar yield and molasses sugar content. In this study, the lowest root sodium content (3.02 ppm), root alkalinity (3.09%) were assigned to transplanting system, also the highest chlorophyll index (36.17%) and the least nitrogen (1.92%), alkalinity percentage was recorded for  Hydro priming treatment (3.24%).The results showed that the highest sugar content  (18.17%), white sugar content (16.14%), sugar extraction (88.96%), shoot dry weight (3.64 kg / ha), root yield ( 82.17t/h), sugar yield (14.89 t/ha) and pure sugar yield (12.24%) and lowest root potassium content (2.52 ppm) were allocated to transplanting system with hydropriming treatment.