Heat Shock Followed by Priming Increases the Quality of Agropyron elongatum Seeds under Accelerated Ageing

The present study was carried out to examine the possibilities of obtaining primed seeds that maintain high germination quality and the same longevity as the untreated seeds. For Tall wheatgrass tested, we found that the desired longevity could be obtained by keeping the seeds under heat shock for a period of several hours, after a priming treatment. Decreasing germination and seedling vigour in BAP 25 and 50 ppm, for 24 priming, did not happen again due to such a treatment. In addition, following priming, heat shock affects the initial quality of primed seeds in some treatments. Optimal temperature was strongly duration dependent. The method was applied to obtain primed seeds without the loss of storability, which is similar to those procedures used to induce desiccation tolerance in germinated seeds and acquire thermo tolerance in plant vegetative tissues

Seed Priming Improves the Germination Traits of Tall Fescue (Festuca arundinacea)

A couple of experiments were carried out to investigate the effects of osmopriming and hydropriming treatments on the germination indexes and seed vigor of Tall fescue (Festuca arundinacea). In the first experiment, fulfilled based on randomized complete block designed with four replicates, the effect of polyethyleneglycol 6000 solution with five osmotic potentials (-8, -10, -12, -14 and -16 bar), two temperatures (15 and 25oC) and four time intervals (12, 24, 36 and 48 hours) was analized. The second experiment was fulfilled by using distilled water at two temperatures (15 and 25oC) and four time intervals (12, 24, 36 and 48 hours) with four replicates on the above mentioned data. Then, based on the maximum germination rate and vigor indexes, the optimal treatment composition was determined for osmopriming and hydropriming solutions in regard to the osmotic potential, temperature and priming duration. In osmopriming experiment, treatment composition of 12 hours at 15oC and -8 bar had the most significant effect on the percent and speed of germination, length of radicle, coleoptile and seedling, as well as vigor indexes in Tall fescue. For hydropriming, the effect analyzed in the same condition as osmopriming, was observed in the majority of evaluated traits; treatment composition of 12 hours prime and 15oC had the maximum numerical value in comparison to control and other treatments. Finally, it is inferred that favorable effects of osmo- and hydropriming at 15oC temperature are more significant in comparison with the control group (none prime seeds)

Evaluation of Nonlinear Regression Models to Describe Seed Germination Response of Mountain Rye (Secale mountanum) to Temperature

The present study sought to evaluate the effect of different temperatures on germination and to determine cardinal temperatures (i.e., base, optimum and maximum) of Secale mountanum at temperatures of 3, 5, 10, 15, 20, 25, 30 and 35oC. Three nonlinear regression models (i.e., segmented, dent-like and beta) were used for quantifying the response of germination rate to temperature. The results showed that in addition to germination percentage, the temperature has a significant impact on germination rate. Given the root mean square of errors (RMSE) of germination time, the coefficient of determination (R2), the simple linear regression coefficients a and b, and the relationship between the observed and the predicted germination rates, the best models for determination of cardinal temperatures of Secale mountanum were dent-like and beta models. Base, optimum and maximum temperatures were estimated to be about 2.70 to 3.17, 21.27 to 30.00 and 35.00 to 35.05°C, respectively for the dent-like model. However, given the high value of SE for temperature base and a negative estimate of the base temperature of the beta model, one can report the dent-like model as the right model. Therefore, by using the dent-like model and the estimated parameters, it is possible to use this model for predicting germination. &nbsp

Increasing Seed Germination Efficiency of Tall Wheat Grass (Agropyron elongatum (Host.) P. Beauv) at Low Temperature and Drought Stress Conditions Using Urea Osmopriming

Seed priming is one of the most important techniques used to improve seed germination under biotic and abiotic stresses. For this purpose, germination and seedling growth characteristics of primed seeds of Tall wheatgrass (Agropyron elongatum (Host.) P. Beauv) were evaluated under drought and low-temperature condition. A factorial experiment was conducted on the basis of randomized completely block design with three factors with four replications. The experimental factors were priming with two levels including urea primed (using urea -4 bar at 10 °C for 36 h) and non-primed seeds germination temperatures, including 3, 6, 9, 12, 15, 20 and 25 °C and osmotic potential including zero (distilled water), -3, -6, -9, and -12 bars (applied by polyethylene glycol 6000). Increasing trend has been observed for all germination indices, except mean germination time, with increasing temperature from 3 to 25 °C and seeds revealed the greatest sensitivity to temperatures below 9 °C. However, this trend was reversed with increasing drought stress, the seeds sensitivity to drought stress started from the potential of -6 bar and reached the maximum in -12 bar. However, primed seeds compared to non-primed seeds have demonstrated better germination under both drought and low-temperature stresses. The results of this study showed that the highest seedling vigor index and germination rates achieved in the temperature range of 20-25 °C and water potential of zero to -3 bar

Study of Different Priming Treatments on Germination Traits of Soybean Seed Lots

Oilseeds are more susceptible to deterioration due to membrane disruption, high free fatty acid level in seeds and free radical production. These factors are tended to less vigorous seed. Priming treatments have been used to accelerate the germination and seedling growth in most of the crops under normal and stress conditions. For susceptible and low vigor soybean seed, this technique would be a promising method. At first, in separate experiment, effects of hydropriming for (12, 24, 36 and 48 h) with control (none prime) were evaluated on germination traits of soybean seed lots cv. �Sari� (include 2 drying method and 3 harvest moisture). Then, next experiment was conducted to determination the best combination of osmopriming in soybean seed lots, hence 3 osmotic potential level (-8, -10 and -12 bar) at 4 time (12, 24, 36 and 48 h) were compared. Analysis of variance showed that, except for seedling dry weight, the other traits include standard germination, germination rate, seedling length and vigor index were influenced by osmopriming. Hydropriming had no effect on these traits and decreased rate of germination. Finally the best combination of osmopriming were osmotic potential -12 bar at 12 hours for time, that submitted acceptable result in all conditions and recommended for soybean seed lots cv. �Sari�