نشریه تحقیقات بذر
پیاپی 26 (بهار 1397)

In order to evaluate the effects of aqueous extract of various organs of Hoary Cress on germination and seedling growth of oat crop a factorial experiment was conducted in a randomized complete block design with 3 replications in 2015 and 2017 in Seed Research Laboratory of Mohaghegh Ardebil University. The treatments were concluded of aqueous extracts of the air and underground parts of the Hoary Cress and a mixture of these organs in equal proportions and at five concentrations of 5, 10, 20, 40 and 80% volumetric. Distilled water was used for control treatment. Based on the results, the aqueous extracts of various organs of Hoary Cress in different concentrations were able to significantly affect on germination and seedling growth of oat (p <0.01) as a result of increasing the concentration of aqueous extract of the Hoary Cress plant, were significantly decreased the germination percentage, germination rate, radicle length, coleoptile length and radicle and coleoptile weight, as well as number of oat derivative roots. In this experiment, the most rate of traits were observed in control and then at 5% concentration of different extracts of Hoary Cress organs and the least traits were observed in 80 and 40% of the extracts of various Hoary Cress organs. Concentration of 80% of the extract of organs aerial, underground and their mixture could reduce almost the total traits of the examined to zero. Based on the results of the threeparameter logistic equation and also based on X50 values, the highest effect of the aqueous extract was belong to Hoary Cress aerial parts and the least effect on the studied traits belonged to the aqueous extracts of underground organs. The results showed that plant debris of Hoary Cress could have inhibitory effects on germination characteristics as well as oat crop growth and development. Then soil should be investigated, in the conditions of field cultivation and at the time of preparation of the seedbed, in terms of the amount of Hoary Cress residues.

In order to study priming on germination, growth and physiological characteristics of Isfahan mass of Fenugreek under salinity stress, a factorial experiment was conducted in a completely randomized design (CRD) with three replications at the Seed Technology Laboratory Faculty of Agricultural Sciences Shahed University in year 2017. The treatments consisted of 5 levels of priming (distilled water) and hydroperimizing distilled water for 24 hours, hydroperimizing distilled water for 48 hours, 3% potassium nitrate and 5% salicylic acid) and Salinity stress in four levels (0, 50, 100 and 150 mM). The results of analysis of variance indicated significant effect of priming and salinity stress on germination, growth, photosynthetic pigmentation and proline content. The results of the comparison of the average effect of the interaction showed that on the germination percentage showed that hydroperiming with 150 mM slinity stress of 100%. According to the results of the comparison, the average of 24 hour hydroperimage in relative traits such as germination speed, shoot length, seedling length, chlorophyll content, carotenoid content and proline content in Indian mass with relative salinity increased compared to other levels. It seems that the herbaceous plant is resistant to stress and the use of hydropriming has improved the effect on the traits compared to other levels.

Germination is one of the most important stages of plant growth that is influenced by environmental stresses. Salinity and drought stresses are remarkable factors in reducing the germination parameters, growth and yield of plants in arid and semi-arid regions. In this experiment, the effect of different levels of drought (0, -2,-4, -6, -8, -10, -12, -14 bar produced by polyethylene glycol) and salinity stress (0, 50, 100, 150, 200, 250, 300, 350 mmol induced by sodium chloride) were evaluated on germination indices of roselle. For this purpose, two separate experiments based on a completely randomized design with 4 replicates were conducted at crop physiology laboratory of Sarayan Faculty of Agriculture, University of Birjand in 2015. Numbers of germinated seeds in each petri-dish were counted and recorded once every 24 hours and germination indices were measured at the end of the eighth day which germination was fixed. Analysis of variance showed significant effects of drought and salinity stresses on the germination and seedling growth parameters of roselle. Drought stress reduced germination characteristics of roselle; where the maximum germination percent and rate were observed in control treatment (84.37% and 6.02 day-1 , respectively) and the minimum amounts of them (4.37% and 0.19 day-1 ) were obtained at -12 bar. The difference between the lowest amount of radical and plumule length under drought stress was 99.4 % compared to control treatment. Furthermore, in salinity stress experiment, the highest amounts of germination percent and rate and plumule and radical length (91.25%, 6.68 day-1 , 45.10 and 31.39 mm, respectively) were obtained in control treatment and the level of 350 mmol induced the lowest germination percent and rate. Totally, roselle had relatively resistance up to -6 bar of drought stress and 100 mmol of salinity stress.

In order to evaluate the effect of drought stress on corn germination indices produced under drought stress on a parent plant, experiment was conducted in a completely randomized design with three replications in a Bahar university in 2017. The factors applied to the mother plant were: full irrigation as control (R1), full flowering stage (R2), pod closure (R3), pod filling (R4), seed start (R5), and complete seeding (R6). The results showed that the highest germination percentage, root length, stem length and dry weight of soybean seedlings were obtained in irrigation treatments throughout the plant life (control). No significant difference was observed between the treatments in the traits and the mean germination time. The lowest dry weight was obtained in drought stress at full flowering stage. Drought stress had an impact on the traits studied and it is recommended that soybeans, especially at full flowering stage, do not undergo drought stress.

Withania somnifera belonging to Solanaceae family. This research was conducted to optimizing the methods of breaking the dormancy of Withania somnifera in two independent experiments. The first experiment was carried out in a factorial arrangement in a completely randomized design experiment with four replications. The first factor was cold treatment at 5 levels (0, 10, 20, 30, 40 days at 4 ° C) and second factor was chemical treatment at 7 levels consist of gibberellic acid (500, 750 and 1000 ppm), potassium nitrate (1000, 2000 and 3000 ppm) and control was distilled water. In the first experiment, the seeds were grown in Murashige and Skoog plant growth medium in test tubes. The second experiment was carried out in the same design as the first experiment but the seeds were cultured after applying cold and chemical treatments inside a petri dish covered with filter paper. Finally, germination percentage, germination rate and average germination rate were calculated. In the first experiment, the highest (100%) and the lowest (15%) germination percentage were seen the treatment of chilling for 10 days + 750 ppm gibberellic acid and control treatment respectively. The application of cold and chemical treatments caused a significant difference in the average germination rate in the tube environment (P<0.01). The minimum germination rate showed in 10 days cold + different amounts of chemical treatment. In the second experiment, application of different treatments caused a significant difference in germination percentage. The highest germination percentage (85%) was observed in 20 days cold + 3000 ppm potassium nitrate treatment. The effects of cold and chemical treatments and their interactions caused a significant difference in germination rate (P<0.01). The minimum germination rate was in 10 days cold + 2000 ppm potassium nitrate treatment. Our results showed that cold period is an essential factor for eliminating of dormancy in Withania somnifera.

Since the seeds of the Lovage hardly germination, in order to evaluate the effect of different treatments on germination of the Lovage seed, a experiment in a randomized completely design with three separate treatments and three replications was conducted to in 2015. The treatments consisted of moist chilling temperature 3, 5 and 7 °C, the duration of moist chilling 3, 6 and 9 weeks and the time of soaking seeds in 0 (control), 12 and 24 hours. The results of analysis of variance the data showed that the effect of different treatment of breaking dormancy on percentage germination and seedling growth indices lovage seeds have a significant effect on the level of five percent. The highest of germination percentage (51.67 and 48.33 percent) and the mean daily germination (0.97 and 0.91 germination per day) were obtained in the time six weeks of moist chilling for soaking seeds in 12 hours. The results showed an increase seedling growth indices (plumule length, plumule diameter, fresh weight and plumule dry weight) in 12 hours seed soaking treatment compared to the control treatment. Also, there was a significant difference between seed soaking treatment and other applied treatments. Therefore, the most appropriate and effective treatment for dormancy breaking physiological Lovage seeds, soaking in water for 12 hours and to chilling at a temperature of five degrees for six weeks .

In order this study the effect of Nano Silver on the growth of Taverniera cuneifolia under salinity stress conditions, an experiment was carried out as factorial based on laboratory conditions (germinator) in summer 2014 on complete randomized design with four replications. Nanosilver particles treatments with 4 levels (0, 30, 80 and 120 mg/l) and salinity treatments (0, 50, 100 and 200 mM) include sodium of salts (NaCl) was considered. Germinated seeds two times in everyday for 30 days in laboratory were counted. Then measured seed germination traits including (radicle length, shoot length, seedling length, seed vigor index, germination percent, germination rate, average time of germination, root fresh weight, root dry weight, plumule fresh weight, plumule dry weight). The results showed that effects of different levels of nano-priming caused significant differences for all traits at one percentage and fresh weight of shoot and radicle at five percent. Also treatment of sodium chloride (salt) also caused a significant difference for all of the traits except germination rate and average time of germination was at the level of one percent. The interaction of nano-priming treatments and sodium chloride also caused difference significant in the percentage of germination, vigor index, length of plumule and radicle and root dry weight. The general result is that concentrations of 30 and 80 mg/l of nanosilver particles had a positive effect on most of the seed germination traits of Taverniera cuneifolia at different levels of salinity stress.

In order to evaluate the effect of seed priming with salicylic acid hormone of germination characteristic on medicinal plant (Lallemantia iberica) under drought stress located. Experiment was implemented as a factorial based on completely randomized design by three replications. Experiment factors consisted of four levels of salicylic acid hormone (0, distilled water, 0.5, 1) and four levels of drought stress (0, -3,-6,-9). Analysis of variance in this study revealed that tested factors have significant effect on characteristics studied (P<0.01). Pre-treatment of salicylic acid was causes to improve seed germination and Lallemantia seedling growth under drought stress. The highest seed and percent germination, seedling vigor, root length, shoot length, shoot fresh weight, seedling dry weight was observed in priming salicylic acid (1 mm) absent drought stress. Overall, results showed that pre-treatment with salicylic acid (1mm) by comparing other level, germination and thereby Lallemantia seedling growth improved.