نوع مقاله : مقالات پژوهشی
نویسندگان
1 گروه اگروتکنولوژی، دانشکده کشاورزی، دانشگاه فردوسی مشهد، مشهد، ایران
2 جهاد کشاورزی شهرستان قوچان، قوچان، ایران.
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Seed germination is the first and most important stage of plant establishment and subsequent successful competition, which is affected by genetic and environmental factors. Temperature and soil water potential are the most important environmental factors. Knowledge of environmental factors controlling seed germination provides the possibility of predicting weed infestation. By obtaining information about the temperature and moisture requirements of weeds, it is possible to manage them successfully. In recent years, the weed of herb-robert has been raised as an invasive weed in rapeseed fields in Mazandaran and Golestan provinces. To investigate the relationship between temperature and germination rate, various cardinal models such as dent-like, segmented, and beta have been used. The purpose of this research is to determine cardinal temperatures in herb-Robert and investigate the role of temperature and drought stress on some of its germination characteristics.
Materials and Methods
To investigate the effect of temperature and drought stress on the germination of herb-Robert (Geranium robertianum L.) seeds, this study was conducted as a factorial experiment within a completely randomized design. The experiment included 8 levels of constant temperature (5, 10, 15, 20, 25, 30, 35, 40 °C) and drought stress in 6 levels (-0.2, 4 -0.0, -0.6, -0.8, -1 MPa) with 4 replications. Germinated seeds were counted up to 14 days after germination. Then indicators such as percentage, germination rate and time to reach 50% germination were calculated. A dent-like regression model was used to determine the cardinal temperature.
Results and Discussion
The results showed that the constant temperature of 20°C has the highest percentage (98%) and germination rate (6.019) under non-stress conditions (zero water potential). Also, germination was stopped at temperatures of 35 and 40 °C. The three-parameters regression model had good accuracy to describe the trend of cumulative seed germination percentage of herb-Robert. The results also showed that with the increase of drought stress, the percentage and rate of germination decreased and at potentials higher than -0.8 MPa, germination stopped. At zero potential (non-stress conditions), the minimum, first optimum, second optimum and maximum temperatures were determined as 1.12, 18.83, 22.76 and 35.09 °C, respectively. With an increase from zero to water potential up to -0.8 MPa, minimum temperature from 1.12 to 4.96, optimal temperatures from 18.83 to 22.76 to 10.51 to 20.63 and maximum temperature from 35.09 changed to 34.48 °C. The results showed that, in each osmotic potential, with increasing temperature, the time to reach 50% germination decreased. On the other hand, with the increase in osmotic potential, this time increased, which indicates a decrease in germination speed. In general, the time to reach 50% germination from 0 to 0.4 MPa potentials started from 6 days and decreased to 3 days. While at higher potentials (-0.6 and -0.8 MPa) it varies in the range of 6 to 8 days. These results indicate that the germination ability of herb-Robert increases in the temperature range of 15 to 20 degrees Celsius at any water potential. Based on the results of this experiment, there was no germination at the osmotic potential of 1 MPa. In general, wild geranium is more tolerant to moderate drought stress (up to -0.6 MPa) in the temperature range of 17 to 22 degrees Celsius, and with increasing drought stress, at lower temperatures (10 to 20 degrees Celsius) its presence will be more.
Conclusion
Based on the results of this study, the highest percentage and rate of seed germination occurred at 20°C. There was no seed germination at temperatures of 35 and 40 °C and water potential of -1 MPa. With the increase of water potential, the minimum temperature increased, the optimal temperatures decreased and the maximum temperature decreased slightly. In general, due to the low minimum temperature, the probability of germination and outbreak of this weed will be higher in colder seasons.
کلیدواژهها [English]
©2023 The author(s). This is an open access article distributed under Creative Commons Attribution 4.0 International License (CC BY 4.0), which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source
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