In order to investigate the effect of seed hardening on GERMINATION percentage and GERMINATION RATE of Common bean (Akhtar cultivar) an experiment was conducted in 2008 in seed laboratory of the Islamic Azad University, Shahre-rey branch. The experimental design was completely randomized design with four replications. Five treatments of seed hardening including, 12 hours soaking and 12 hours drying of seeds at three times, 12 hours soaking and 12 hours drying of seeds at four times, 24 hours soaking and 24 hours drying of seeds at tree times, 24 hours soaking and 24 hours drying of seeds at four times and no hardening of seeds (control) were studied. Results showed that the effect of seed hardening on GERMINATION percentage and GERMINATION RATE was significant at p< 0.01. Soaking and drying of seeds in comparison with control treatment, increased GERMINATION percentage and GERMINATION RATE. The highest GERMINATION percentage (99.25%) and GERMINATION RATE (1.77 days) was achieved in 24 hours soaking and 24 hours drying of seeds at four times.

Evaluating of an appropriate model is critical for quantifying the response of GERMINATION RATE to temperature and determination of cardinal temperatures. This study was conducted to evaluate different nonlinear regression models to describe response of GERMINATION RATE to temperature in Salvia species. The regression models were dent-like, segmented and beta. Root mean squareof error, coefficient of determination, correlation coefficient and regression of predicted values versus observed ones were used to find the appropriate model(s). Dent-like and segment models were superior compared to the Beta model in Salvia species. It was concluded that these models can be used to quantify response of Salvia species GERMINATION to temperature and to obtain cardinal temperature of GERMINATION. These parameters are required to predict Salvia species GERMINATION and emergence.

It is very important to find the best model to quantify seed GERMINATION RATE on the response of temperature which it can be used in determination of cardinal temperatures. This study was conducted to evaluation nonlinear regressions models for description wheat (cv. Morvarid) GERMINATION RATE response to temperatures and water potentials. Therefore, seeds GERMINATION RATE were evaluated in temperatures of 5, 10, 15, 20, 25, 30 and 37oC and water potentials of 0, -0.2, -0.4, -0.6 and -0.8 MPa. Four functions (Dent-like, Segmented, Beta (original) and Beta (Modified)) were evaluated to describe GERMINATION RATE on the response to temperature and water potentials. The results indicated that the best model was Dent-like which can better estimate GERMINATION RATE in response to temperature and water potential. The base, the lower and the upper and the ceiling temperatures were 1.5, 23.8, 33.0 and 41.0oC in the optimum conditions of water potential. Cardinal temperatures had no significantly change under different water potentials, except for base temperature. Biological time for GERMINATION ranged from 34 to 51 h in different water potentials. Biological time increased about 20 h by decreasing 1 MPa. Estimated parameters and the relations can be used to prediction time to GERMINATION or emergence in wheat under wide environmental conditions from normal to drought stress.

Iran is located in a hot and dry region. As a result of low precipitation and a vast area of salty and alkali soil, osmotic pressure is very high in most parts of the country (i.e., osmotic potential is more negative). In the present study four levels of osmotic pressure (-0.25, -0.35, -0.45, -0.50 MPa) were created artificially, by polyethylene glycol (PEG) and treatment of three seed types, namely, barley, corn and canola. The study aimed at finding the seeds with better GERMINATION potential under high osmotic pressure. The seeds' GERMINATION potential under different levels of osmotic pressure was also investigated. The experiment was conducted with four replications at the Laboratory of Faculty of Agriculture, Islamic Azad University, Saveh Branch, in a completely randomized design. Parameters under study were GERMINATION RATE and GERMINATION percentage. Results showed that GERMINATION RATE was not affected by osmotic potential. Considering GERMINATION percentage, only osmotic potential of -0.50 reduced GERMINATION percentages of corn seeds. Levels of osmotic potential did not affect seed GERMINATION in barley and canola.

The GERMINATION and emergence are the most critical stages of plant life, because seeds are exposed to unfavorable environmental factors at this stage and plant establishment is confronted with difficulty.Therefore, prediction of GERMINATION time is one of the main goals of simulation researchers. In this regard mathematical techniques such as determination of the best nonlinear regression function which can quantify response of GERMINATION RATE to temperature and estimate the cardinal temperatures would be very informative about characteristics and plants thermal requirements at this stage. The present study was conducted using a factorial experiment arranged in completely randomized design with three replications in 2010. The experimental factors including 19 temperature levels (12-48˚C at intervals of 2˚C from each other) and six rice (Oryza sativa L.) genotypes namely Binam, Hashemi, Anbarbou (landrace varieties), Dasht, Gil3 (Iranian improved cultivars) and IR64 (IRRI improved cultivar). Analysis of variance showed that there are significant differences between studied genotypes and genotype´temperature interaction effect for GERMINATION RATE. The models of beta, quadratic, curvilinear, dent-like and segmented were applied to describe the relationship between GERMINATION RATE and temperature. The comparison of different criteria for evaluating of the studied models showed different precision of the fitted models so that the segmented model for Hashemi variety, the beta model for Dasht and Gil3 varieties, the curvilinear model for Anbarbou and IR64 varieties and the beta and curvilinear models for Binam variety were the better than the other models. Results of current study showed that the mentioned models and their estimated cardinal temperatures can be used to predict the GERMINATION time and simulation of the studied rice varieties.

The effects of the physical factors on dielectric characteristics of wheat biological parts were studied. Due to the sensitivity of phytochromes to the red light, the activity of the related enzymes as well as the inner energy and seed entropy during GERMINATION can be increased through irradiation He-Ne laser light to the plant seed with the wave length of 623nm, which, in turn, leads to the increased energy exchange between the seed and the environment. In this research, wheat varieties as Shiroudi, Zagros, Tajan and Kouhdasht were used under the He-Ne laser (623nm, 0.1 mW/mm-2) in time periods of 10, 15, 20, 25 and 30 minutes. Moreover, in order to investigation the radial effects of laser on the traits of the rootlet and the stemlet length on the fresh weight of stemlet and rootlet, number of seedlings, drought weight of stemlet and rootlet, and seed GERMINATION, four cultivars of wheat in five replication with factorial experiment as completely randomized design (CRD) have been studied. The results indicated that Zagros variety and Shiroudi variety had the fastest RATE of seed GERMINATION, with 0.942(N/d) and 0.910(N/d), respectively. The result of this research indicates that cultivar Zagros with 0.006(grf), had he highest drought weight of rootlet among the cultivars. Also results showed that cultivar Zagros had more growth and drought weight of stemlet among the cultivars.

The study was conducted to collect germplasm and identify appropriate seed treatment technique to enhance GERMINATION of Bouffordia dichotoma syn. Desmodium dichotomum, which is self-generating wild legume forage growing in eastern Amhara (North Wollo, South Wollo and Oromia Special Zones), Ethiopia. Twenty six Desmodium dichotomum seed populations (1000 seeds from each) were collected in 2018 from fields using Ethiopian biodiversity institute sample population collection format by considering agro ecological similarity and physical barrier to genetic mixing. The samples were collected from sorghum growing farm-lands. Breaking of dormancy in seeds of Desmodium dichotomum collections was investigated through laboratory experiment to elucidate the best method that can be used to enhance GERMINATION of the seed. To test the effectiveness of pre sowing treatments on GERMINATION of Desmodium dichotomum collected seed lots, the following treatments were imposed under a completely randomized design with 3 replications of 60 seeds each: mechanical scarification by sand paper,boiled water at 100oC for 4 minutes,and untreated seeds as control. GERMINATION percentage was highest (p < 0. 05) for scarification (99. 4%) followed by boiled water (79. 15%) and untreated seeds (36. 58%), respectively. Mechanical scarification greatly reduced GERMINATION time as most seeds (68. 7%) sprouted in the first 5 days and GERMINATION was completed at day 9. Similarly, boiled water made sprout the seeds in the first 5 days (65%) and completed GERMINATION at day 10. However, non-treated seeds had started to germinate at day 12 (1%). Scarification by sand paper was quite effective in increasing GERMINATION of Desmodium dichotomum collected seeds. Further improvements in GERMINATION of Desmodium dichotomum could be expected in different boiling water temperature with different minutes and acid treatment methods.

The improvement of vegetation due to full or partial protection was depicted by most of rangeland scientists. This study investigated the effect of livestock grazing on percentage of GERMINATION (PG), mean growth time (MG) and GERMINATION RATE (GR) of the even-aged Atriplex canescens, by comparing two sites across zarand, shahreiar rangelands located in the southwest of Tehran, Iran. For this purpose, the seeds of 30 A. canescens within each of the two study sites were collected and a quantitative analysis of the seeds was carried out by laboratory analysis. The results indicated that, grazing had no significant influence on PG, MGT and GR.