نوع مقاله : مقاله پژوهشی
نویسندگان
1 استادیار، گروه علوم کشاورزی، دانشکده فنی و مهندسی، دانشگاه پیام نور، تهران، ایران
2 دانشیار، گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه بوعلی سینا، همدان، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
Microplastic contamination of agricultural lands is one of the major environmental problems that has recently gained attention. The decomposition of plastic mulches and equipment used in irrigation systems, the use of sludge-based fertilizers from wastewater purification, contaminated irrigation water, and the proximity of fields to busy roads are among the most important factors in the contamination of agricultural lands with plastic particles. The presence of microplastics in the soil with particle sizes from 100 nm to five mm causes abrasion of the root surface of plants, and physical damage to plant roots will increase with increasing particle size. Moreover, drought stress, as one of the most important factors limiting crop production, is increasing alarmingly, especially due to global climate change. Therefore, the present study was conducted to investigate the possibility of using the biological potential of the fungus Piriformospora indica to reduce the negative effects of stress caused by polyvinyl chloride (PVC) microplastic particles and water deficiency in maize crop.
Materials and methods
The experiment was conducted as factorial experiment in a completely randomized design with three replications in the research greenhouse of Bu-Ali Sina University, Hamadan, Iran, in 2023. The experimental factors included the addition of three concentrations of polyvinyl chloride microplastics to the soil (0, 0.1, and 1%), P. indica fungus at two levels (inoculation and non-inoculation), and water deficit stress at three levels (full irrigation, and irrigation at 75% and 50% of field capacity, as non- stress, moderate stress and severe stress, respectively). Germinated maize seeds (cv. ‘Tah’) were inoculated with P. indica, planted in pots containing three kg of soil, and placed in greenhouse conditions. Water deficit stress was applied 14 days after planting. One month after planting, photosynthetic parameters and relative leaf water content were measured. The plants were then harvested, and the roots were assessed under a microscope to determine the colonization percentage. Proline content, total chlorophyll content, and plant dry matter were also measured.
Research findings
The results showed that the presence of 1% microplastic in the soil, similar to water deficit stress, significantly reduced relative leaf water content, total chlorophyll content, photosynthetic indices, and shoot dry matter of maize seedlings. Although the percentage of root colonization of maize seedlings by P. indica fungus decreased by 16.9%, 30.9%, and 47.1% under 1% microplastic contamination and water deficit at 75% and 50% of field capacity conditions compared to the control, respectively, the beneficial effects of the fungus on plant growth and measured parameters was still evident, so that the relative leaf water content, chlorophyll content, net photosynthesis rate, and shoot dry weight of inoculated plants under the highest level of water deficit stress and in the presence of 1% microplastic were (8.2 and 9), (20.5 and 27), (17.9 and 17.8) and (43.5 and 46.8) percent higher than those of uninoculated plants, respectively. Moreover, the proline content of the plants also increased significantly in the presence of the fungus.
Conclusion
The results of this study showed that the presence of P. indica fungus improved the growth and photosynthetic parameters of maize seedlings under microplastic particles and water deficit stress conditions. Thus, utilizing the potential of this fungus can be considered to reduce the negative effects of these stresses.
کلیدواژه‌ها [English]
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