Quantifying cardinal temperatures and thermal time for seed germination of Papaver dubium and P. rhoeas

ABSTRACT

Background

Temperature plays a key role in plants distribution. Cardinal temperatures are important parameters for plant population dynamics models.

Aims

This study was conducted to estimate the cardinal temperatures and other parameters in relation to temperature using three non-linear regression models (segmented, dent-like and beta) to project the germination rate and temperature relation of Papaver dubium and P. rhoeas.

Methods

An optimisation method was used to fit the models and their statistical parameters. Their efficiency was compared with the coefficient of determination (R²), root mean square error (RMSE) and the Akaike Information Criterion.

Results

Calculated cardinal temperatures differed for different germination percentiles (10, 30, 50%). The time required to 50% germination of both P. dubium and P. rhoaes was more accurate than the time required to 10% and 30% germination between observed and predicted values. According to the outputs of the segmented model, base, optimum and maximum temperatures of P. rhoeas were 1.9°C, 22.4°C and 39.6°C, respectively. The corresponding values for P. dubium were 2.1°C, 22.1°C and 39.1°C.

Conclusions

The parameters related to temperature provide the basic information to determine the time needed for germination and to project potentially suitable areas for invasion. The segmented model is appropriate for the estimation of the cardinal temperatures of both Papaver species.

KEYWORDS:

• Base temperature
• germination rate
• modelling
• temperature response
• thermal time

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Author contributions

S. Golmohammadzadeh, F. Zaefarian and M. Rezvani designed the study; S. G. collected samples and carried out the measurements; S. G. and F. Z. analysed the and interpreted the data; S. G., wrote the manuscript, and F. Z., M. R. and B. S. Chauhan edited the manuscript.

Additional information

Notes on contributors

Sajedeh Golmohammadzadeh

Sajedeh Golmohammadzadeh is a Ph.D. student in crop ecology and weed science. Her research interests are in the ecophysiology of seeds and weed herbicide resistance.

Faezeh Zaefarian

Faezeh Zaefarian is an associate professor. Her research interests are agroecology and weed management.

Mohammad Rezvani

Mohammad Rezvani is an associate professor with research interests in agroecology and weed management.

Bhagirath S. Chauhan

Bhagirath S. Chauhan is a professor. His research interests are seed ecology, weed biology, climate change, herbicide resistance, cultural weed management, and integrated weed management.