كليدواژه :
آنتي‌اكسيدانت , جوانه‌زني , زوال , هدايت‌الكتريكي
چكيده فارسي :
زوال يك پديده طبيعي است كه در همه بذرها رخ مي‌دهد و منجر به كاهش تدريجي توان زيستي بذر در طي انبارداري مي‌گردد. سرعت زوال به وضعيت فيزيولوژيكي و ساختار ژنتيكي بذرها و شرايط انبارداري بستگي دارد. به‌منظور بررسي اثر زوال بر شاخص‌هاي جوانه‌زني و فعاليت آنزيم‌هاي آنتي‌اكسيدانت در كتان روغني (رقم نورمن)، آزمايشي به‌صورت فاكتوريل در قالب طرح كاملاً تصادفي در 4 تكرار در سال 1394 در آزمايشگاه بذر دانشگاه ياسوج انجام شد. فاكتورهاي آزمايش شامل نگهداري بذور در بسته‌هاي آلومينيومي دربسته به مدت 6 ماه در 4 سطح دمايي 15، 25، 35 و 45 درجه سانتي‌گراد و رطوبت 5، 9، 13 و 17 درصد بود. نتايج نشان داد كه با افزايش دما و رطوبت بذر، كليه صفات فيزيولوژيك و بيوشيميايي به جز هدايت الكتريكي، كاهش يافتند. كاهش جوانه‌زني با كاهش فعاليت آنزيم‌هاي آنتي‌اكسيدانت كاتالاز، سوپراكسيد ديسموتاز و آسكوربات پراكسيداز همراه بود كه بيانگر كاهش كارايي سيستم آنتي‌اكسيدانتي در حفاظت بذرها در مقابل گونه‌هاي فعال اكسيژن مي‌باشد و باعث افزايش پراكسيداسيون چربي‌ها، تخريب غشاهاي سلولي و نشت الكتروليت‌ها از بذر شده است كه همبستگي قوي و منفي بين نشت الكتروليت‌ها و فعاليت آنزيم‌هاي آنتي‌اكسيدانت نشانگر اين مسئله است. هم‌چنين بذور كتان با محتواي روغن و پروتئين محلول بالا درصد جوانه‌زني بيشتري داشتند اما زوال‌پذيري بيشتري نيز نشان دادند و بايد به شرايط محيط انبارداري آن‌ها بسيار دقت نمود. به‌طور‌كلي، نتايج به‌دست آمده از پژوهش حاضر بيانگر اين است كه بهترين شرايط نگهداري بذر كتان دماي 15 درجه سانتي‌گراد و رطوبت 5 درصد مي‌باشد.
چكيده لاتين :
Background and Objectives
Seed deterioration is a natural phenomenon that occurs in all seeds and leads to gradual decline of
seed viability during storage. However, the rate of seeds age depends upon their physiological
status, genetic constitution and storage conditions. The lipid peroxidation through the production
of free radical plays an important role in the loss of seed viability during seed storage.
Material and Methods
In order to investigate the effect of deterioration on germination indices and enzymes activity of
the flax oil seed, a factorial experiment was conducted based on a Completely Randomized
Design with four replications in the seed laboratory of Yasouj University in 2015. The factors
included 4 levels of temperature (15, 25, 35 and 45oC) and moisture content (5, 9, 13 and 17%).
With relation intended seed moisture, Hampton and Teckrony (1995) was calculated. After
determining the moisture content of the seeds in envelopes of aluminum foil was placed, then the
amount of water the need added and to ensure that the packaging and moisture exchange with the
outside world for 24 hours at 15 °C were identical to the seed moisture and then for 6 months in
storage conditions at temperatures of 15, 25, 35 and 45oC were kept.
Results
Analysis of variance showed that the single effects including temperature and seed moisture
content experimental treatments for traits including germination percentage, germination rate,
seedling vigor index (weight), activity enzymes antioxidant catalase, superoxide dismutase and
ascorbate peroxidase, soluble proteins, electrical conductivity and oil percentage were significant
(P≤0.01). Also, the interaction temperature and seed moisture content of all treatments except for
enzyme, activity of superoxide dismutase and ascorbate peroxidase were significant (P≤0.01) but
were significant (P≤0.05) for the activity of superoxide dismutase and ascorbate peroxidase. The
results showed that with increasing temperature and moisture content, all the physiological and
biochemical traits, except for electrical conductivity, decreased. The decrease in germination was
also associated with a decrease in the activity of antioxidant catalase, superoxide dismutase and
ascorbate peroxidase and as a result the antioxidant system was not sufficient to protect seeds
against free radical damage. With the increase in reactive oxygen species, lipids peroxidation
increased, probably due to the destruction of cell membranes, increased electrical conductivity
seed the negative correlation between the electrical conductivity and the activity of the enzymes
antioxidant indicator of the issue.
Discussions
Thus, oil flax seed deterioration was closely related to decrease in the activities of free radical
detoxifying enzymes and increased lipid peroxidation. In general, the best flax seed storage
condition is at 15°C and 5 percent moisture content.
