Elham Bahrabadi; R. Tavakkol Afshari; Mehdi Nassiri Mahallati
Abstract
In order to evaluate the effect of temperature, drought and priming on the percentage and rate germination of corn seeds, a factorial experiment based on a completely randomized design with four replicates was conducted. Treatments included eight temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ºC), ...
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In order to evaluate the effect of temperature, drought and priming on the percentage and rate germination of corn seeds, a factorial experiment based on a completely randomized design with four replicates was conducted. Treatments included eight temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ºC), four drought potential (0, -0.4, -0.8 and -1.2 MPa), and five priming (control, hydroprimin, GA priming, ABA priming and, SA ptiming). Both percentage and rate of germination were inhibited at osmotic potentials ≤−0.8 MPa PEG. At 35 ºC temperature. Germination percentage of unprimed seeds was reduced from 94 to 36% in −1.2 MPa. Under these conditions, gibberellic acid hormone treatment improved seed germination. The effect of temperature on germination can be defined in terms of cardinal temperatures. We compared three non-linear regression models (Dent-like, segmented and beta). The outcome revealed that the Dent-like function was suitable for use in describing seed germination response to temperature. The base, optimum 1, optimum 2 and ceiling temperature were estimated to be 9.51, 24.12, 35 and 44.62 °C, respectively. The response of germination rate to both temperature and water potential can be described as a non-linear function of the hydrothermal model. According to the results of this study, hydropriming, gibberellic acid, and salicylic acid increased the mean deviation of the base temperature compared to non-priming treatment, increasing the standard deviation of the base temperature indicates the ability of seed germination in different osmotic potentials.
A.R. Rabiei; A. Nezami; M. Goldani; M. Khajeh-Hosseini; M. Nassiri Mahallati
Abstract
Harvesting of medicinal plants from their natural habitats, put them in danger, hence their domestication is needed. In this context, knowledge of the properties of these plants, including the cardinal germination temperatures are necessary. In order to determine the cardinal temperatures and the effect ...
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Harvesting of medicinal plants from their natural habitats, put them in danger, hence their domestication is needed. In this context, knowledge of the properties of these plants, including the cardinal germination temperatures are necessary. In order to determine the cardinal temperatures and the effect of temperature on the percentage and rate of germination in Plantago major ecotypes (Birjand, Ghaen, Torbathydarieh, Mashhad, Kalat and Bojnord) an experiment was conducted based on factorial in a completely randomized design with 9 temperature levels (5, 10, 15, 20, 25, 30, 35, 40 and 45 °C) and four replications in Crop Physiology Laboratory, Ferdowsi University of Mashhad in 2013. To determine the cardinal temperatures Intersected-Lines Model and Five-Parameters Beta Model were used. Results showed that maximum germination percentage was obtained at 30 °C while maximum germination speed achieved at 35 °C in Bojnourd and Birjand ecotypes, respectively. The highest germination percentage was observed in Birjand ecotype at the temperature range of 20 to 35 °C. Based on models fitted depending on the ecotype, cardinal temperatures (minimum, optimum and maximum) germination were determined (6.3 to 9.8, 1.8 to 5°C) ,(31.1 to 35.9, 28.6 to 35.2°C) and (43.3 to 45.1, 45 to 45.6 °C) of Intersected-lines and Five-Parameters Beta Model, respectively. Diversity in cardinal temperature of plantago major ecotypes could be due to different environmental conditions where they were evolved and adapted
