Quantifying of germination response in dill (Anethum graveolens L.) to temperature and drought stress by hydrothermal time model

Document Type : Research Paper


1 Agricultural faculty, High educational complex of Torbat-e Jam

2 Agriculture faculty , High Educational Complex of Torbat-e Jam, khorasan Razavi, Iran


Temperature and water are the most important environmental factors controlling seed germination in ‎plants. In order to investigate the effect of temperature and drought stress on seed germination and ‎quantifying of germination; a factorial experiment was conducted with eight temperature levels including ‎‎5, 10, 15, 20, 25, 30, 35 and 40 degrees Celsius and the seven levels of drought stress including 0, 0.5-‎‎0.0, -0.2, -0.3, -0.4, -0.5 and -0.6 MPa, respectively. The results showed that the germination was ‎decreased by decreasing osmotic potential at all temperature levels. However, the intensity of this ‎decrease was less in the range of 20 to 30°C. Using two different methods, the base and maximum ‎temperature of dill germination was estimated in the range of 2.3 and 2.9 °C and 43.0 and 47.3 °C, ‎respectively. The optimum temperature for dill germination was 26 °C. The estimated value of base ‎water potential for germination was -0.53 Mpa with the hydrothermal time model. The results also ‎showed that water base potential for dill germination was increased by -0.5 Mpa as temperature ‎increased. Finally, it was found that if the base water potential taking into account variable in response to ‎changing temperature, then the hydrothermal time model can be good enough to quntify dill germination ‎response to temperature and water.‎


Main Subjects

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Volume 50, Issue 1
May 2019
Pages 107-118
  • Receive Date: 22 January 2018
  • Revise Date: 11 July 2018
  • Accept Date: 21 July 2018
  • Publish Date: 22 May 2019