نوع مقاله : مقالات پژوهشی
نویسندگان
دانشگاه فردوسی مشهد
چکیده
هر گونۀ گیاهی از نظر نحوه واکنش جوانه‌زنی به درجه حرارت، دارای تنوع ژنتیکی خاصی است.از آنجا که جوانه‌زنی مرحله بحرانی در چرخه زندگی گیاهان می‌باشد. لذا به منظور تعیین درجه حرارت‌های کاردینال در پنج رقم چمن (فستوکا اروندیکا آستریکس، فستوکا اروندیکا الدورادو، فستوکا اروندیکا استارلت، لولیوم پرن و برموداگراس) در 8 سطح درجه حرارت (5، 10، 15، 20، 25، 30، 35 و40 درجه سانتی‌گراد ) آزمایشی به صورت فاکتوریل در قالب طرح کاملاً تصادفی با چهار تکرار در آزمایشگاه تحقیقات دانشکده کشاورزی دانشگاه فردوسی مشهد انجام شد. نتایج نشان داد که درصد جوانه‌زنی، سرعت جوانه زنی، طول ریشه‌چه، طول ساقه‌چه، نسبت طول ریشه‌چه به ساقه‌چه و شاخص بنیه گیاهچه تحت تاثیر درجه حرارت، ارقام چمن و برهمکنش رقم و درجه حرارت در سطح احتمال یک درصد قرار گرفتند. بیشترین صفات مورد مطالعه در درجه حرارت 25 درجه سانتی‌گراد ، بیشترین درصد (91%) و سرعت جوانه زنی (138 تعداد در روز) در رقم آستریکس و حداکثر طول ریشه‌چه (95/2 سانتی‌متر)، طول ساقه‌چه (35/3 سانتی‌متر) در رقم لولیوم و حداکثر شاخص بنیه گیاهچه (36/0) در رقم الدورادو مشاهده شد. درجه حرارت بالاتر و پایین تر از درجه حرارت مطلوب کاهش معنی داری در مقادیر مذکور را بدنبال داشت. بین ارقام چمن از نظر واکنش به دماهای کاردینال تنوع وجود داشت. به نظر می‌رسد علت این تنوع دمایی مربوط به ساختار ژنتیکی گیاه و سازگاری‌های تکاملی (گرمسیری و سردسیری) می‌شود که این گیاهان کسب کرده اند.
کلیدواژه‌ها
عنوان مقاله [English]
Determination of Cardinal Temperatures and Germination Respond to Different Temperature for Five Lawns Cultivars
نویسندگان [English]
- Hadi Khavari
- Morteza Goldani
- Mohmmad Khajehossaini
- Mahmood Shoor
Ferdowsi University of Mashhad
چکیده [English]
Introduction: Germination of every plant species respond to temperature variation in particular way. Germination is critical stage in plant life cycle. Seed germination is a complex biological process that is influenced by various environmental and genetic factors. The effects of temperature on plant development are the basis for models used to predict the timing of germination. Estimation of the cardinal temperatures, including base, optimum, and maximum, is essential because rate of development increases between base and optimum, decreases between optimum and maximum, and ceases above the maximum and below the base temperatures. Usually, a linear increase in germination rate is associated with an increase in temperature from base temperature (Tb) to an optimum. An increase of temperature from the optimum will reduce the germination rate to zero. To determine the best planting date for plants, it is necessary to find the base (Tb), optimum (To) and maximum temperatures (Tc) for seed germination. These are known as cardinal temperatures. Modelling of seed germination is considered an effective approach to determining cardinal temperatures for most plant species, although these methods have some limitations due to unpredictable biological changes. The results of fitting mechanical models are useful for evaluating seed quality, germination rate, germination percentage, germination uniformity and seed performance under different environmental stresses such as salinity, drought, and freezing. Regression models incorporating more parameters can produce more precise estimates. Cardinal temperature was determined using segmented and logistic models in millet varieties and seedling emergence of wheat. In the dent-like model at lower-than-optimum temperature, a linear relationship holds between temperature and germination rate. This relationship remains linear at higher-than-optimum temperatures, but with a reducing trend. With increasing temperature, germination rate increases linearly up to an optimum temperature.
There are many cultivars of turfgrasses available each year and this large number can make your choice difficult. This guide is designed to help you decide which cultivars to use from those that have performed well in tests in Mashhad and are commercially available. When choosing a turf grass, consider the environmental aspects of where you plan to establish the turf and the cultural techniques that you will use to manage the grass and then choose the appropriate grass for your situation.
Materials and Methods: In order to determine cardinal temperatures in five cultivars of turfgrass (Festuca arundinacea asterix, Festuca arundinacea eldorado, Festuca arundinacea starlet, Lolium perenne and Bermuda grass) in eight temperature levels (5, 10, 15, 20, 25, 30, 35, 400C), factorial experiment was conducted in completely randomized design with four replications in research laboratory of Faculty of Agriculture, Ferdowsi University of Mashhad.
In the end of experiment measuring the following indices:
Final Germination Percentage (FGP) and Germination Rate (GR) were calculated based on below equation:
FGP= (n / N) × 100
In this equation, n is the number seed germination at the end of the trial and N is the total of seeds.
GR=
gi: the number of seed germination in every count and di:the number of days to counting until n-th day.
The base (Tb), optimum (To) and maximum temperatures (Tc) for seed germination were calculated based on below equation.
وx≤T0 y= ax2 + bx+ c
Data was analysis with MSTAT-C, Minitab ver, 13 and Excel software and means were comparative with Dunkan multiple range test in 5 percent probability.
Results and Discussion: Results showed that the germination percent, germination rate, radical length, plumule length, root to shoot and seedling vigor index are affected by temperature, variety and them interaction (P
کلیدواژه‌ها [English]
- Cardinal temperatures (max, opt and min)
- Lawns cultivars
- Seedling vigor
)
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