نوع مقاله : مقاله پژوهشی

نویسندگان

گروه علوم خاک، دانشکده کشاورزی، دانشگاه فردوسی مشهد، صندوق پستی: 48978-91779، مشهد ایران

چکیده

اورانیم فلزی سنگین و پرتوزا است که به طور طبیعی در پوسته­‌ی زمین یافت می‌­شود. فعالیت‌­های انسان در برخی موارد منجر به افزایش مقدار اورانیم در برخی مناطق زمین شده است. به منظور بررسی اثر مایکروریزا و فسفر بر جذب اورانیم در گیاه آفتاب­گردان، مطالعه‌­ای در قالب طرح کاملاً تصادفی با آرایش فاکتوریل شامل یک سطح اورانیم (100 میلی­گرم بر کیلوگرم(، سه سطح مایکروریزا شامل شاهد، گلوموس اینترارادیسز و گلوموس موسه و دو سطح فسفر (20 و 60 میلی­گرم بر کیلوگرم) در گلخانه­‌ی پژوهشی دانشگاه فردوسی مشهد انجام شد. گیاهان بعد از یک دوره­ی 60 روزه برداشت شدند. وزن خشک گیاه، مقدار اورانیم و فسفر و میزان جذب اورانیم در بخش هوایی و ریشه اندازه­‌گیری شد. نتایج نشان داد که مایکروریزا باعث افزایش مقدار زیست توده و بنابراین افزایش مقاومت گیاه به تنش ناشی از سمیّت اورانیم شد. هم­چنین مایکروریزا باعث افزایش مقدار اورانیم در اندام­‌های هوایی و ریشه­‌ی گیاه آفتاب­گردان شد. تیمار فسفر وزن خشک اندام‌­های هوایی، وزن خشک ریشه‌ی گیاه، مقدار اورانیم در بخش هوایی گیاه آفتاب­گردان را به طور معنی‌­داری افزایش داد. نتایج همچنین نشان داد که مایکروریزا مقدار اورانیم در ریشه را چندین برابر مقدار آن در بخش هوایی افزایش داده و از این­رو می‌­تواند به عنوان گزینه­‌ای مناسب برای افزایش تثبیت اورانیم در خاک مورد استفاده قرار گیرد.

کلیدواژه‌ها

عنوان مقاله [English]

Effects of Mycorrhiza Fungi and Phosphorous on Uranium Uptake by Sunflower

نویسندگان [English]

  • S Bagherifam
  • A Lakzian

چکیده [English]

Uranium is a radioactive element that occurs naturally in the earth’s crust. However, in some areas its natural abundance has been redistributed due to anthropogenic activities, where consequently results in high levels of contamination. In order to study the effect of mycorrhiza fungi and phosphorus on the uranium uptake by sunflower, a pot experiment is conducted under a controlled greenhouse condition. The experiment was carried out in a completely randomized design with three factors, including three species of arbuscular mycorrhizae (Glomus mosseae, Glomus intraradices, non-mycorrhizae), two levels of phosphorous (20 and 60 mg/kg), and one level of uranium (100 mg/kg). Plants were harvested after 60 days of experiment and dry weight of root and shoot as well as the uranium and phosphorus concentration in the shoot and root were determined. The results showed that mycorrhizae fungi increased the resistance of the plant against heavy metals. Also, mycorrhizae increased the uranium and phosphorous contents in the shoot and root of the sunflower plant. The dry weights of the shoot and root and also the uranium concentration in the shoot of the sunflower plant were significantly augmented by increasing phosphorus level. The results revealed that mycorrhiza symbiosis raised the uranium concentration in the root more than the shoot. Thus, it seems that arbuscular mycorrhiza has a potential for enhancing the phytostabilization of the sunflower plant.

کلیدواژه‌ها [English]

  • Uranium
  • Mycorrhizae
  • Phosphorous
  • Sunflower
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