تأثیر برخی عوامل محیطی بر جوانه¬زنی و دوام بذور علف¬پشمکی Bromus tectorum))

نوع مقاله: مقاله پژوهشی

نویسندگان

دانشگاه بیرجند

چکیده

اثر عوامل محیطی بر جوانه‌زنی و دوام بذور علف‌پشمکی در شرایط آزمایشگاهی و مزرعه تحقیق شد. علف پشمکی قادر به جوانه‌زنی در طیف وسیعی از دما (6/15، 10/20، 15/25، 15/30 و 20/35 درجه سانتی‌گراد) بود. با این وجود درصد جوانه‌زنی بسته به دامنه دمایی متفاوت بود و نتایج نشان داد که حداکثر جوانه‌زنی علف‌پشمکی در دمای 10/20 درجه سانتی‌گراد (91 درصد) در تاریکی مداوم و حداقل آن در دمای 20/35 درجه سانتی‌گراد (5 درصد) در روشنایی/تاریکی رخ داد. شوری بالا بازدارندۀ شدید جوانه‌زنی علف‌پشمکی بود، به طوری که بیشترین جوانه‌زنی در غلظت صفر میلی‌مولار کلرور سدیم (شاهد) رخ داد (89 درصد). افزایش غلظت شوری جوانه‌زنی را بشدت کاهش داد و جوانه‌زنی در غلظت 320 میلی‌مولار کاملاً متوقف شد. نتایج این مطالعه نشان داد که افزایش pH در دامنه 4 تا 8 سبب افزایش درصد جوانه‌زنی این علف‌هرز شد. افزایش pH به بالاتر از 8 باعث کاهش معنی‌دار درصد جوانه‌زنی شد. در آزمایش دیگری که بذور در اعماق مختلف خاک در مزرعه پس‌رسی شدند، افزایش عمق دفن بذر از صفر تا 10 سانتی‌متر سبب تسریع در پس‌رسی و جوانه‌زنی شده و کمترین جوانه‌زنی در سطح خاک مشاهده شد.

کلیدواژه‌ها


عنوان مقاله [English]

Effects of Some Environmental Factors on Germination and Longevity of Downy Brome (Bromus tectorum) Seeds

نویسندگان [English]

  • sead vahid eslami
  • fatemeh afghani
  • sohrab mahmoodi
چکیده [English]

The effects of environmental factors on germination and longevity of downy brome seeds were examined in laboratory and field experiments. Downy brome could germinate in a broad range of temperatures (15/6, 20/10, 25/15, 30/15, and 35/20ºC). The germinability, however, was different depending on the temperature range and the results showed that the highest germination was occurred in 20/10ºC (91%) under continuous dark regime, while the lowest germination percentage was observed in 35/20ºC (5%) under light/dark conditions. Salinity showed significant adverse effect on germination of this weed, so that the highest germinability was at 0 concentration of NaCl (89%). Increased salinity levels significantly decreased downy brome germination and its germination completely ceased at 320 mM NaCl. This study indicated that increasing pH in the range of 4 to 8 resulted in enhanced germination percentage, while further increase of pH significantly reduced germinability. Another experiment in which seeds were after-ripened at different depths in the field showed that increased burial depths from 0 to 10 cm accelerated seed after ripening and the lowest germination occurred in the seeds which were placed on the soil surface.

کلیدواژه‌ها [English]

  • acidity
  • After-ripening
  • Germination
  • Salinity

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