Effect of Seed Deterioration on Physiological and Biochemical Traits of Oil Flax (Linum usitatissimum L. Norman var.) Seed

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 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.
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.
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.