نوع مقاله : مقاله کامل علمی پژوهشی
نویسندگان
1 دانشجوی دکتری علوم علفهایهرز، گروه تولید و ژنتیک گیاهی، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل، ایران
2 استاد، گروه تولید و ژنتیک گیاهی، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل، ایران
3 بخش تحقیقات گیاهپزشکی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان اردبیل (مغان)، سازمان تحقیقات آموزش و ترویج کشاورزی، مغان، ایران
4 دانشآموخته دکتری رشته آگروتکنولوژی دانشگاه محقق، اردبیل، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Abstract
Background and Objective: Wild mustard (Sinapis arvensis) is a major weed in wheat fields, which causes serious problems for farmers due to its high competitive ability, abundant seed production, and herbicide resistance. To date, 533 herbicide-resistant weed biotypes have been reported, and this herbicide family is one of the groups to which resistance has been widely observed worldwide; so far, 172 weed species have developed resistance to this family (1). Fluorescence parameters are suitable indicators for assessing the damage caused by herbicides. Since tribenuron-methyl is an inhibitor of the enzyme acetolactate synthase, and this enzyme is located in the chloroplast, evaluating wild mustard's resistance to tribenuron-methyl by examining chlorophyll fluorescence can be valuable.
Materials and Methods: This study was conducted in the spring of 2013 at the research farm of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, as a factorial split plot based on a completely randomized design with 3 replications. The first factor was wild mustard biotype at 2 levels (susceptible and resistant to the herbicide tribenuron-methyl), the second factor was the herbicide concentration of tribenuron-methyl (WP%50) at 7 levels (0, 5, 10, 15, 20, 25, and 30 g/ha), and the third factor was the sampling time at 5 levels (3, 5, 7, 9, and 12 days after spraying).
Results: Tribenuron-methyl caused a greater increase in minimum fluorescence and thermal dissipation of photosystem II reaction centers, as well as a decrease in maximum fluorescence, variable fluorescence, and the maximum quantum efficiency of photosystem II in the susceptible biotype compared to the resistant biotype. This indicates that the photosynthetic system efficiency in the susceptible wild mustard is lower when exposed to herbicide doses. This could suggest an inability of the photosynthetic pigments to absorb solar radiation and transfer electrons to chlorophyll a located in the reaction center of photosystem II. In the susceptible biotype, fluorescence levels peaked 9 days after herbicide application and then declined, decreasing by 13.39% on day 12 and 25.37% on day 15 compared to the levels recorded on day 9. In contrast, the resistant biotype showed an increasing trend in fluorescence until day 9, followed by a decrease by day 12 after herbicide application. Variable fluorescence in the untreated control of susceptible wild mustard showed a significant decrease on day 7 compared to other days, indicating the occurrence of environmental stress, likely due to higher light intensity on that day. Chlorophyll content was significantly influenced by the interaction between herbicide dose, wild mustard biotype, and sampling time. Three days after treatment, all herbicide doses increased chlorophyll concentration in the susceptible wild mustard compared to the control. Conversely, in the resistant biotype, all herbicide doses reduced chlorophyll concentration at all time points after application. The lowest chlorophyll concentration was observed 5 days after application at the 5 g ha⁻¹ dose, which was 14.73% lower than the control treatment.
Conclusion: The results showed that tribenuron-methyl caused a greater increase in minimum fluorescence (F₀) and thermal dissipation in photosystem II (PSII) reaction centers, along with a decrease in maximum fluorescence (Fm), variable fluorescence (Fv), and the maximum quantum efficiency of PSII (Fv/Fm) in the susceptible biotype compared to the resistant biotype. This indicates lower photosynthetic system efficiency in susceptible wild mustard when exposed to herbicide doses, which could be attributed to the inability of photosynthetic pigments to absorb solar radiation and transfer electrons to the chlorophyll a dimer in the PSII reaction center.
کلیدواژهها [English]
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