نشریه تحقیقات بذر
پیاپی 33 (زمستان 1398)

temperature and light in a completely randomized design with 8 surface temperature (5,10,15,20,25,30,35,40 Degrees centigrade) in terms of continuous light and continuous darkness with 4 replicators at the research laboratory of Ramin Ahwaz Agricultural and Natural Resources University in 2017. The results showed that temperature and light treatments had significant effect on germination percentage, seedling vigor, root length and shoot length. Temperature of 35 ° C and constant light conditions showed the highest germination percentage. Cardinal temperatures for germination of base temperature, the optimum temperature and maximum temperature, respectively, 7/6, 34/6 and 40 ° C respectively. The highest seed vigor index was observed at 35 ° C and continuous light conditions.

Salicylic acid is an important intermediate molecule for the response of plants to environmental stresses. To study the effect of seed priming by salicylic acid on germination of milk thistle under salinity stress, a factorial experiment was conducted based on completely randomized design in three replications in 1394 at the Islamic Azad University, Miyaneh. Treatment was conducted seed priming with salicylic acid each with four levels (0, 100, 200 and 300 mg/L) and four NaCl levels (0, 40, 80 and 120 mM/L). The end of experiment, germination percentage, germination rate, root length, seedling length, seedling fresh weight, root fresh weight, vigor index seed and vigor index seedling were measured. Increase in salinity concentration reduced germination indices but priming by salicylic acid under salinity had improved on germination indices. The most appropriate level of salicylic acid was to reduced salinity effects and improve germination with 200 mg/L salicylic acid with or without salinity stress. Therefore, seed priming by salicylic acid with 200 mg/L can cause resistance of seed milk thistle under salinity stress.

In order to investigate the effect of seed priming to resist drought stress of basil, a research was carried out in plant research laboratory of Islamic Azad University, Neyshabur Branch, in 2018, in a completely randomized design with in vitro and greenhouse conditions. Both stages consisted of four levels of PM with varying concentrations of polyethylene glycol solution (control, -3 bar, -6 bar, -9 bar). In the first stage, drought levels included four levels of drought stress (control, -3 bar, -6 bar). The second stage consisted of three levels of drought stress (control (100 percent field capacity), 75 percent field capacity, 50 percent field capacity). The results showed that drought stress can have significant effects on the percentage of germination components (germination percentage, germination rate, germination index, root and shoot fresh weight and root and shoot dry weight) and basil plant growth. Level (P≤0.01) in laboratory and greenhouse stages. In greenhouse only root length, mean number of leaves per plant and secondary leaf area were significant. In addition, the interaction effects of priming on drought stress also showed significant effects on the percentage of germination and growth of basil (P≤0.01) at laboratory and greenhouse stages. Due to the climate and approach to medicinal plants, more research is needed.

Germination step is one of the most important stages of market garden plants growth that may be negatively affected by chemical substances that are circulated by other plants in the soil environment.For study effects of weeds allelopathy Nut grass (Cyperus rotundus) which is one of the common weeds in the tomato fields. A study was conducted on the percentage and speed of germination and the length of colohrize and coleoptile of tomato plants in the laboratory conditions. The test treatments included extracts extracted by distilled water from dried leaves, which in five concentration (0-25-50-75 %) on tomato cultivars, consist of Cal ji and Chef Fallat American applied. The experiment was carried out in factorial design with a complete randomize design in four replication. The results of the analysis variance showed that the highest and lowest percentage of germination on the Chef Fallat American and the lowest rate of germination on the chef plateau U.S.A on the average (1.66%). Comparison between means show that among treatments had significant different ,the density of 100 % of Nut grass had a negative effect on the rate of germination in the total number of Col ji, but the Chef Fallat American was the highest negative effect on the germination rate at concentrations of 50 and 75%. As the Nut grass concentration increased, the length of the colohrize affected a decrease, which was higher in the Col ji figure. The highest length of coleoptile in the total cultivar of Col ji and Chef Fallat American howed a significant difference. In experimental conditions, the seeds of tomato plants were strongly affected by the inhibitory effects from the germination and colohrize growth due to the weed extract, which depend heavily on the concentration of the extract.

One of the consequences of the prevailing drought, reduced water potential in the field of seeds. High negative water potential, especially in the early stages of germination, leading to reduced water uptake by seeds and prevent the continuation of the process of germination..This research is conducted to study the effect of priming by chemical hormones on the medicinal plant seed of Lallemantia in early growth stages, and also its effect on germination indexes and its role in the reduction of negetive effects of environmental stresses under draught conditions, in factorial form based on completely randomized design with four repeats, which was done in the labrotory of agricultural educational center of East Azarbijan, Tabriz in 2015. The first factor in both tests comprised priming with salicilic acid in three levels (100, 200, 300 mg/lit.), ascorbic acid (100, 200, 300 mg/lit), and oxin in three levels (50, 100, 150 ppm), and distilled water as control. The second factor comprised draught test with 5 levels of Ethylene glycol( 0, -0.3, -0.6, -0.9, -1.2 megapascal). Lab results were analysed usind SAS software and statistical method of CRD. Variance analysis results showed that priming and draught treatments had significant effect on germination characteristics of Lallemantia seed at 1% sigificance level, while the negetive effect of these stresses on priming-received seeds was remarkabaly weaker than seeds whith no priming. Among all pre-treatments used, maximum effect on Lallemantia germination characteristics in stress conditions under study, attributed to salicilic acid 200 mg/lit., and minimum effect to oxin 50 ppm.

In order to investigate the level of jimson weed seed dormancy, a factorial experiment based on Randomized Complete Blocks Design was conducted in three replications during 2019 in Karaj. First Factor was seven jimsonweed population comprised (Karaj, Ghazvin, Zarghan, Gorgan, najafabad, Neyshaboor and Naghadeh), second factor was three moisture regimes (moisture level )dry, alternate wetting and drying and moisture) and third factor was four temperatures of seed storage (temperatures in four months of the seed rain to restart growth integrated December and January, February and March, April and at the end of May and June). After applying each treatment, germination test was performed at 20°C. The 3-parameters sigmoid function described well the germination trends in jimsonweed populations against different levels of seed storage temperature. Temperature played an important role in breaking dormancy in jimsonweed seed. As the temperature increased under seed storage conditions, the levels of dormant seed populations diminished, but soil moisture conditions had an effect on the type of response during seed burial. In light conditions and in all soil moisture content, Karaj population had more germination rate than other populations. In dry soil and under dark conditions only Zarghan population succeeded in germination. Neyshaboor and Najafabad populations failed to break dormancy in dark conditions. Therefore, due to the sensitivity of the seeds of these populations to light at the germination stage, they can be controlled to some extent before planting a crop through the management of plowing operations.

In order to evaluate the effect of pre- treatments on germination characteristics and seedling growth of sugar beet under salinity stress, an experiment was conducted in a completely randomized design with three replications at Seed technology laboratory of Collage of Agriculture, Shahed University in 2016. The factors were pre-treatment of salicylic acid at two levels (0.3 and 0.6 mM), pre-treatment of Hydroprim (24 and 48 hour) and salinity stress (zero, -3, -6 and -9 ds.m-1). Result analysis of variance showed that effect diferent pre- treatment on Total germination percentage, Normal germination percentage, Ubnormal germination percentage, Root Length, Shoot Length, Seedling Lenght , Mean germination time, Uniformity germination and SV II index at the 1% level was significant. Also, effect salinity stress on germination characteristics showed that effect salinity stress on Total germination percentage, normal germination percentage, unormal germination percentage, Root Length, Shoot Length, Seedling Length, Mean germination time, SV II index at the 1% level was significant. The effect intraction of pre-treatment and salinity stress on all traits at probability level 1 percent, was significant. The results showed that highest seed germination percentage (50%) related to the per- treatments with salicylic acid 0.6 mM and no salinity stress and lowest the germination percentage (21.25) related to treatment shahed and salinity stress -9 ds.m-1 . Highest and lowest the SV II index related to the per- treatments Hydroprim 48 hour and salinity stress -9 ds.m-1 (3805.5) and shahed and salinity stress -9 ds.m-1 (530. 5), respectively. Generally, in order to break dormancy and high SV II index of sugar beet, pre- treatment seed with salicylic acid 0.6 mM is recommended.