Mohammad khademi; Faezeh Zaefarian; Shahram Nazari; Mohammad Ali Esmaelee
Abstract
In order to investigate the effect of hydropriming and osmopriming on the characteristics of experimental rice seedlings, the treatment was performed in a completely randomized design in three replications.Treatments included two rice cultivars (Tarom and Shiroudi) and priming at five levels including ...
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In order to investigate the effect of hydropriming and osmopriming on the characteristics of experimental rice seedlings, the treatment was performed in a completely randomized design in three replications.Treatments included two rice cultivars (Tarom and Shiroudi) and priming at five levels including calcium chloride and potassium chloride priming (Ψs -1.25 MPa), ascorbate acid (10 mg l-1), hydropriming (for 48 hours) and control (no priming). In this study, seedling characteristics were measured. Interaction of cultivar and priming showed that the highest germination percentage was observed in the range of 97-100% in Shiroudi and Tarom cultivars primed with calcium chloride and potassium chloride. The lowest germination percentage (85.33% and 77.33%, respectively) was obtained under control in Shiroudi and Tarom cultivars, respectively. The highest germination rate was obtained in priming with calcium chloride and potassium chloride, which increased the germination rate by 52 and 54%, respectively. The effect of cultivar and priming on root and shoot length as well as root and shoot dry weight were significant at 1% probability level. also, root and shoot length were 5.97 and 5.4 cm in Shiroudi and 4.01 and 4.59 cm in Tarom, respectively. The results showed that priming with calcium chloride, potassium chloride, ascorbic acid and water increased seedling length vigor indices 69, 64, 13 and 32% in Shiroudi and 91, 70, 47 and 43% in Tarom, respectively compared to control. Also, priming with calcium chloride, potassium chloride, ascorbic acid and water increased seedling weight vigor indices by 110, 95, 50 and 47%, respectively.
R. Deihimfard; Sh. Nazari; Y. Qorani
Abstract
In order to evaluate different nonlinear regression models for estimating cardinal temperatures of Lepyrodiclis holosteoides as an invasive weed, an experiment was carried out at Biodiversity Laboratory of Environmental Sciences Research Institute at Shahid Beheshti University. 8 germination temperatures ...
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In order to evaluate different nonlinear regression models for estimating cardinal temperatures of Lepyrodiclis holosteoides as an invasive weed, an experiment was carried out at Biodiversity Laboratory of Environmental Sciences Research Institute at Shahid Beheshti University. 8 germination temperatures (0, 5, 10, 15, 20, 25, 30 and 35 °C) and humidity potential (0, -0.2, -0.4, -0.6 and -0.8 MPa) with four replications. Were arranged in a completely randomized design with for replications. Then, germination rate and percentage of seeds were measured. To predict the response of germination rate to temperature in Lepyrodiclis holosteoides, some regression models including dent-like, segmented, beta (four and five parameters) were applied. Some statistical estimators like Root Mean Squared of Error (RMSE), Akaike Information Criterion (AIC) and coefficient of determination (R2) were used to evaluate goodness of fit for different regression models. Results showed that the highest germination percentage (72%) was obtained at 20 °C. Results also indicated that beta four and five-parameter models were amongst the superior functions in describing the response of germination rate to temperature in Lepyrodiclis holosteoides largely due to their higher R2 (0.99 for both beta models), lower AIC (-73.16 and -73.27) and RMSE (0.0092 and 0.0091). Generally, base, optimum and ceiling cardinal temperatures for Lepyrodiclis holosteoides were estimated 4.29, 19.76 and 37.55 °C for beta four-parameter models and 4.22, 19.72 and 37.83 °C for beta five-parameter model. The findings of the current study (i.e. cardinal temperatures) could be used in prediction of Lepyrodiclis holosteoides germination and emergenceunder various temperatures.
