اثر دود و حرارت بر رکود و جوانه‌زنی بذر علف‌هرز کنجدشیطانی

نوع مقاله : مقاله پژوهشی

نویسندگان

• آسیه سیاهمرگویی
• فرشید قادری فر
• سید حمیدرضا باقری

گروه زراعت، دانشکده تولید گیاهی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران.

چکیده

کلیدواژه‌ها

• آتش
• بانک بذر
• بذر علف‌های هرز
• دود
• جوانه‌زنی
• دما

عنوان مقاله [English]

Effect of smoke and heat on dormancy and germination of Asian spiderflower seeds

نویسندگان [English]

• Asieh Siahmarguee
• Farshid Ghaderifar
• S. Hamid Reza Bagheri

کلیدواژه‌ها [English]

• dormancy
• fire
• germination
• seed bank
• smoke
• weed seeds

Extended Abstract

Introduction

    A suitable strategy for weed management is to target the weed seed bank in the soil by encouraging seed germination and reducing the number of weed seeds in the soil seed bank. Research showed that high temperatures and smoke from burning plant residues (which is done to facilitate bed preparation operations) affect the behavior of weed seeds in the soil seed bank. As a result, this research was conducted to investigate the effect of smoke from the burning of rapeseed residues on the dormancy and germination of Asian spider flower seeds.

Material and Methods

     This study was conducted on fresh and 6-month after-ripened seeds. In the first experiment, the germination of fresh and after-ripened seeds was examined at temperatures ranging from 15 to 40 ^oC under light and dark conditions. In the second experiment, Asian spider flower seeds were pre-treated for 5 and 10 minutes at high temperatures of 80, 100, 120, and 150 ^oC and then the seeds were germinated at the temperature of 30 °C. In the third experiment, the effect of smoke on the germination of fresh and after-ripened seeds was studied using charred solution, smoke water, and aerosol smoke.

Results

     The highest percentage of germination of this plant was observed at the temperature of 30°C and all temperatures, the percentage of germination was higher in light conditions (12.12 hours) than in darkness. The fresh seeds of the Asian spider flower did not germinate at any temperature, but the germination of after-ripened seeds at 30 ^oC was 92%. The seed germination of this weed was higher in light than in darkness. Pre-treatment with high temperatures did not affect the germination of freshly harvested Asian spider flower seeds. Pre-treatment of ripened seeds with temperatures of 100, 120, and 150 °C caused complete inhibition of germination, and the germination percentage was 84-87% only in the seeds that were pretreated at 80°C temperature. Freshly harvested Asian spider flower seeds did not germinate under different treatments of charred solution, smoke water, and aerosol smoke. At a temperature of 30 °C, different concentrations of charred solution and smoke water did not affect the germination of this weed; but different trends were seen in other temperatures. The use of different concentrations of charred solution increased the germination rate compared to the control. In imbibed seeds, the germination percentage of this weed was similar in different treatments (including the time of exposure to aerosol smoke and washing or not washing the seeds).  However, in dry seeds, the germination percentage and rate in the non-washing treatment were higher than in the washing treatment. Also, in dry seeds, the germination percentage increased with increasing exposure time to aerosol smoke.

Conclusion

     Studies have shown that the seeds of different species of Cleome have a non-deep physiological dormancy. The application of various treatments, including after-ripening for 6 to 12 months at a temperature of 20 to 30 °C, is effective in improving the germination of these plants. Studying the survival of ungerminated seeds in pre-treatment conditions with high temperatures showed that all seeds were alive. This indicates that the high temperatures caused by the fire cause the induction of dormancy in the Asian spiderflower seeds. The results of the present study showed all smoke treatments had positive effects on seed germination of Asian spider flowers. The positive effects of smoke treatments are in the following order: aerosol smoke>smoke water> charred solution. In light and dark conditions at a temperature of 30 °C (optimum temperature for germination of this weed), different concentrations of > charred solution and smoke water did not affect the germination behavior of this plant; However, at temperatures lower and higher than the optimal temperature, the maximum seed germination of this weed was affected by light and darkness and the concentration of smoke extract. Thus, the use of smoke treatments can partially replace the role of light in seed germination. Considering that the weed seed bank is made up of newly dropped seeds by the mother plant and seeds produced in previous years, it seems that the smoke resulting from the burning of plant residues can improve the germination conditions in older seeds and this order will empty the seed bank of this weed in the soil.