جوانه زنی دو گونه مرتعی Helichrysum globiferum و Helichrysum aucheri تحت تنش خشکی
محورهای موضوعی : جنگلداری
زینب جعفریان
1
(استادیار دانشگاه علوم کشاورزی و منابع طبیعی ساری)
الهه احمدی
2
(دانش آموخته کارشناسی ارشد مرتعداری دانشگاه علوم کشاورزی و منابع طبیعی ساری)
کلید واژه: تنش خشکی, سرعت جوانه زنی, درصد جوانه زنی, ضریب آلومتری,
چکیده مقاله :
با توجه به اینکه قسمت اعظم کشور را مراتع خشک و نیمه خشک تشکیل داده است، گیاهان این مناطق باید سازگار به کمبود آب باشند. استفاده از گونه های مرتعی مقاوم به خشکی در امر اصلاح و توسعه مراتع دارای اهمیت فراوانی است. بر این اساس تاثیر تنش خشکی بر جوانه زنی دو گونه Helichrysum globiferum و Helichrysum aucheri در قالب یک طرح آزمایشی به صورت فاکتوریل در 4 تکرار و 4 سطح خشکی (0-50-100-150 مگاپاسکال محلول پلی اتیلن گلایکول 6000) انجام شد. بذرهای این دو گونه از مراتع قوشچی واقع در 70 کیلومتری جاده قدیم ارومیه – قره باغ جمع آوری گردید. نتایج این تحقیق نشان داد که در نتیجه تنش خشکی، درصد و سرعت جوانه زنی، طول ساقه چه، ریشه چه و گیاه چه در هر دو گونه به طور معنی داری کاهش می یابد. مقدار این کاهش در همه صفات در گونه Helichrysum globiferum کمتر از گونه Helichrysum aucheri بوده، نسبت طول ریشه چه به ساقه چه (ضریب آلومتری) نیز در گونه Helichrysum globiferumدارای بالاترین مقدار بود، بنابراین می توان نتیجه گرفت که این گونه مقاوت بیشتری نسبت به گونه ی دیگر دارد. همچنین بیشترین کاهش جوانه زنی در تیمار 100 و 150 میلی مول بود بطوریکه در تیمارهای مذکور هیچ بذری جوانه نزد.
Abstract Arid and semi-arid rangelands are formed the most areas of Iran, hence it is necessary to be tolerant the plants of this region against drought. Using of resistant species to drought is vital for improving and developing of the rangelands. In this study, we evaluated the effects of drought stress on Helichrysum globiferom and Helichrysum aucheri germination properties. Seeds of two species were collected of Qushchy rangelands in 70 kilometers of the old road of Urmia –Karabakh. A factorial experimental design with four repeats and four salinity levels (0-50-100-150 mM PEG) in Seed Ecology laboratory of Sari Natural Resource Faculty was chosen. Results showed that drought stress had a significant subtractive effect on percentage and speed of germination, stem, and plant and root length in two Species. About all studied traits, the species of Helichrysum globiferom had more reduction properties than Helichrysum aucheri species. The ratio of Root to shoot length (allometric coefficient) also was the highest in Helichrysum globiferom. So the highest decrease in both species was observed in germination in treatment 100 and 150 mM because in this treatment no seed is germination. Therefore, as the species of Helichrysum globiferom is more resistant than another one, it is suggested to use it for improving and developing of rangelands.
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