Seed aging is the main
problem of seed storage. Changes of
enzyme activity and reduction of seedling
growth are consequence of seed
deterioration. An experiment was conducted
to evaluate the effects of accelerated aging
on germination indexes and enzyme activity
of barley seeds. Seeds were incubated in
closed plastic boxes for the accelerated
aging treatments at 41°C. Three accelerate
aging regimes were performed by placing
seeds at 41°C and relative humidity (RH) of
90-100 % for 0, 4 and 8 day periods. Our
results showed that increasing aging
duration resulted higher reduction in
germination percentage, germination index,
mean time to germination, normal seedling
percentage, catalase and ascorbate
peroxidase. The highest germination
percentage, germination index, normal
seedling percentage and enzyme activity
were achieved in control conditions (0 day
of aging). Under aging conditions,
germination percentage, means time to
germination, germination index, normal
seedling percentage and enzyme activity
decrease significantly. Also, our results
indicated that seed aging is related to
decrease of enzymes and may contribute to
low germination efficiency. The general decreases
in enzyme activity in the seed
lowers the respiratory capacity, which in
turn lowers both the energy (ATP) and
assimilates supply of the germinating seed,
also decrease in antioxidant enzymes is
linked to an increased accelerated ageing
and decreased germination characteristics.
Subsequently, proposed a positive
relationship between antioxidant enzyme
capacity and the vigour of the seed

Tabatabaei, S.A.

Cercetari Agronomice in Moldova

ALSE Repository

THE EFFECT OF AGING ON GERMINATION OF BARLEY SEEDS   61  Cercetări Agronomice în Moldova Vol. XLVIII , No. 2 (162) / 2015   THE CHANGES OF GERMINATION CHARACTERISTICS AND ENZYME ACTIVITY OF BARLEY SEEDS UNDER ACCELERATED AGING  S. A. TABATABAEI1*  *E-mail: tabataba4761@yahoo.com  Received Mai 18, 2014                                                       1 Faculty member, Agricultural and Natural Resources Research Center of Yazd, Iran ABSTRACT. Seed aging is the main problem of seed storage. Changes of enzyme activity and reduction of seedling growth are consequence of seed deterioration. An experiment was conducted to evaluate the effects of accelerated aging on germination indexes and enzyme activity of barley seeds. Seeds were incubated in closed plastic boxes for the accelerated aging treatments at 41°C. Three accelerate aging regimes were performed by placing seeds at 41°C and relative humidity (RH) of 90-100 % for 0, 4 and 8 day periods. Our results showed that increasing aging duration resulted higher reduction in germination percentage, germination index, mean time to germination, normal seedling percentage, catalase and ascorbate peroxidase. The highest germination percentage, germination index, normal seedling percentage and enzyme activity were achieved in control conditions (0 day of aging). Under aging conditions, germination percentage, means time to germination, germination index, normal seedling percentage and enzyme activity decrease significantly. Also, our results indicated that seed aging is related to decrease of enzymes and may contribute to low germination efficiency. The general de-creases in enzyme activity in the seed lowers the respiratory capacity, which in turn lowers both the energy (ATP) and assimilates supply of the germinating seed, also decrease in antioxidant enzymes is linked to an increased accelerated ageing and decreased germination characteristics. Subsequently, proposed a positive relationship between antioxidant enzyme capacity and the vigour of the seed.  Key words: Germination characteristics; Enzyme activity; Barley seed; Aging.  INTRODUCTION  Barley (Hordeum vulgare L.) is a common crop grown in the semiarid Mediterranean area, and due to its drought resistance, is one of the most widely grown crops in arid and semiarid regions of the world (Ghazi et al. 2007). Seed deterioration can be defined as the loss of quality, viability and vigour either due to aging or effect of adverse environmental factors. S.A. TABATABAEI   62 Seed characteristics decrease under long storage condition due to aging. It is the reason of declining in germination, emergence and seedling growth (Soltani et al., 2008). All organisms undergo aging and it enhances under unfavorable or stress environments. Maximum germination percentage achieves immediately after harvesting and gradually decreases with storage time. Aging is one of the key factors in plant yield loss especially in vegetables. Seed aging is recognized by some parameters like delay in germination and emergence, slow growth and increasing of susceptibility to environmental stresses (Walters, 1998). Using high quality seed improved performance in two ways: first, percent of green seedling derived by high quality seeds is more than weak and exhausted ones and this can be helpful to achieve the desired density in field. Second, vigorous seed had more seedling growth rate and ununiformed emergence in germination time can be minimized (Ghasemi-Golezani et al., 1996). High temperature, ambient relative humidity, and seed moisture content are the main factors influencing seed storage capability (Abdul-Baki, 1980).  Pandey et al. (1990) reported that accelerated ageing technique is a widely used tool to test the seed quality. This ageing test of seed vigor can give better indications of probable field emergence for vegetable crop seeds than germination and growth tests. Accelerated ageing initially proposed as a method to evaluate seed storability, this test is rapid, inexpensive, simple and useful for all species (Copeland and McDonald, 2001; Moradi and Younesi, 2009; Siadat et al., 2012). Accelerated ageing techniques have great potential for understanding the mechanism of aging and associated deterioration processes of seeds (McDonald, 1999). Janmohammadi et al. (2008) and Ghassemi-Golezani et al. (2010) in rape seed and Saha and Sultana (2008) in soybean reported that increasing seed age decreased germination. Most of these studies suggest that decreases occur in the activity of enzymes in aged seeds (Bailly, 2004; Goel et al., 2002; Mc-Donald, 2004).  Therefore, in the present study it has been investigated the changes of germination characteristics and enzyme activity of barley seeds under accelerated aging.  MATERIALS AND METHODS  The study was conducted in the Faculty member, Agricultural and Natural Resources Research Center of Yazd, Iran. For accelerated aging treatments seeds were then imposed to different accelerated ageing periods of 0, 4 and 8 days at 41°C in sealed ageing boxes which had 100% relative humidity. After that, a germination test was conducted. Standard germination test was carried out at 20°C for 7 days in three replications of 50 seeds. Seeds were germinated on two layers of filter papers (Whatman no. 1) moistened with 5 ml distilled water in Petri dishes. The germinated seeds (2 mm radicle elongation) were counted daily to THE EFFECT OF AGING ON GERMINATION OF BARLEY SEEDS   63 calculate germination rate. At the end of the germination period, total and germination percentage, normal seedling percentage, germination index and mean time to germination were recorded.  For antioxidant enzymes assay, all extraction procedures were carried out at 4°C. About 0.2 g of seed samples were homogenized with 10 ml of phosphate buffer (pH 7), followed by centrifugation at 20,000 g for 15 min. The supernatants were used for determination of enzyme activity. Catalase (CAT, EC 1.11.1.6) activity was determined spectrophotometrically, following H2O2 consumption at 240 nm (Bailly et al., 1996). Ascorbate peroxidase (APX, EC 1.11.1.7) activity was determined according to the procedures of Al et al. (1995). The activities of APX and CAT were expressed per mg protein, and one unit represented 1 μmol of substrate undergoing reaction per mg protein per min. Data of percentage was subjected to data transformation (arcsine) before the statistical analysis in order to unify the variance of the data (Siadat et al., 2012; Ansari et al., 2012). Data of experiment were subjected to randomized complete design. Statistical analyses on collected data performed with SAS and Microsoft Excel software. Mean comparisons were performed using an ANOVA protected least significant difference (Duncan) (P < 0.01) test.  RESULTS AND DISCUSSION  According to our results of variance analysis, effect of priming treatments on germination percentage, germination index, normal seedling percentage and mean time to germination, under aging conditions were significant (P < 0.01) (Tab. 1). In agreement with the results, earlier reports (Pandey et al., 1990; Bailly, 2004; Goel et al., 2002; McDonald, 2004; Siadat et al., 2012) have shown negative affect cold stress on germination characteristics.  Table 1 - Analysis of variance of studied traits barley seeds under accelerated aging  S.O.V. df Germination percenrage Germination index Mean time to germination Normal seedling percentage Treatment 2 3724** 494.59** 0.68** 4484.77** Error 6 4 0.3 0.04 0.77 CV%  3.4 2.83 8.69 1.71 ** indicate significant difference at 1% probability level.   Our results showed that the highest germination percentage (Fig. 1), germination index (Fig. 2), mean time to germination (Fig. 3), normal seedling percentage (Fig. 4) and the minimum were achieved under control conditions (0 day of aging), but with increases of duration of aging this traits reduction. Therefor the minimum this traits were attained under 8 days of aging.   S.A. TABATABAEI   64  Figure 1 - The effect of accelerated aging on germination percentage of barley seeds   Figure 2 - The effect of accelerated aging on germination index of barley seeds   Figure 3 - The effect of accelerated aging on means time to germination of barley seeds THE EFFECT OF AGING ON GERMINATION OF BARLEY SEEDS   65  Figure 4 - The effect of accelerated aging on normal seedling percentage of barley seeds   Figure 5 - The effect of accelerated aging on enzyme activity of barley seeds  Increasing seed age decreased germination and this result is in accordance with Janmohammadi et al. (2008) and Ghassemi-Golezani et al. (1996) in rapeseed and Saha and Sultana (2008) in soybean. Also, earlier reports (Pandey et al., 1990; Bailly, 2004; Goel et al., 2002; McDonald, 2004; Moradi and Younesi, 2009; Siadat et al., 2012) have shown negative effect of aging in relation to seed performance, germination percentage and seedling indices. Akhter et al. (1992) suggested that decreasing in GP was related to chromosomal aberrations that occur under long storage conditions. Decreasing of GP in aged seeds can be due to reduction of α-amylase activity and carbohydrate contents (Bailly, 2004) or denaturation of proteins (Nautiyal et al., 1985). According to Abdalla and Roberts (1968) barley and pea seeds treated with different combinations of accelerated ageing treatment showed that the amount of genetic damage was solely a function of loss of viability. Also, our results showed that enzyme activity decreased in S.A. TABATABAEI   66 seeds after aging (Fig. 5). Most of these studies suggest that decreases occur in the activity of enzymes in aged seeds (Bailly, 2004; Goel et al., 2002; McDonald, 2004). Kibinza et al. (2011) reported that the CAT is a key enzyme in seed recovery from ageing during priming.   CONCLUSIONS  In general, our results clearly indicate that decline in germination characteristics in response to aging is a consequence of decline in enzyme activity in barley seeds. The highest germination characteristics and enzyme activity were attained under control conditions (0 day of aging). Decreasing of germination percentage in aged seeds can be due to reduction of enzyme activity. The general de-crease in enzyme activity in the seed lowers the respiratory capacity, which in turn lowers both the energy (ATP) and assimilates supply of the germinating seed, also decrease in antioxidant enzymes is linked to an increased accelerated ageing and decreased germination characteristics. Subsequently, proposed a positive relationship between antioxidant enzyme capacity and the vigour of the seed. Therefore, several changes in the enzyme macromolecular structure may contribute to their lowered germination efficiency.  REFERENCES  Abdul-Baki A.A., 1980 - Biochemical aspects of seed vigor. HortScience, 15: 765-771. Abdalla F.H., Roberts E.H., 1968 - Effects of temperature, moisture and oxygen on the induction of chromosome damage in seeds of barley, broad beans and peas during storage. Ann Bot (N.S.), 32: 119-136. Al A., Bestwerk C.S.., Barna B., Mansfield J.W., 1995 - Enzymes regulation the accumulation of active oxygen species during the hypersensitive reaction of bean to Pseudomonas syringae pv. Phaseolicola. Planta, 197:240-249. Akhter F.N., Kabir G., Mannan M.A, Shaheen N.N., 1992 - Aging effect of wheat and barley seeds upon germination mitotic index and chromosomal damage. J Islam Acad Sci, 5:44-48. Ansari O., Choghazardi H.R., Sharif Zadeh F., Nazarli H., 2012 - Seed reserve utilization and seedling growth of treated seeds of mountain rye (Secale montanum) as affected by drought stress. Cercetări Agronomice în Moldova, 2 (150): 43-48. Bailly C., 2004 - Active oxygen species and antioxidants in seed biology. Seed Sci Res, 14:93-107. Bailly C., Benamar A., Corbineau F., Côme D., 1996 - Changes in malondialdehyde content and in superoxide dismutase, catalase and glutathione reductase activities in sunflower seeds as related to deterioration during accelerated ageing. Physiol Plantarum, 97:104-110. Copeland L.O., McDonald M.B., 2001 - Principles of seed science and technology. 4th edition. Kluwer academic publishers, pp. 176. Ghasemi-Golezani K., Salehian H., Rahimzade-Khoee F., Moghadam M., 1996 - The effect of seed vigor on seedling emergence and yield of wheat. Natural Resources and Agricultural Sciences, 3: 58-48. Ghazi N., Karaki A., Al-Ajam A., Othman Y., 2007 - Seed germination and early THE EFFECT OF AGING ON GERMINATION OF BARLEY SEEDS   67 root growth of three barley cultivars as affected by temperature and water stress. American-Eurasian J Agri and Environ Sci, 2(2): 112-117. 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McDonald M.B., 2004 - Orthodox seed deterioration and its repair, pp. 273-304. In: Handbook of Seed Physiology: Applications to Agriculture, Benech-Arnold, R. L. and R.A. Sanchez (Eds.). Food Products Press, New York.  McDonald M.B., 1999 - Seed deterioration: physiology, repair and assessment. Seed Sci Technol, 27: 177-237. Moradi A., Younesi O., 2009 - Effects of Osmo- and Hydro-priming on Seed Parameters of Grain Sorghum (Sorghum bicolor L.). Australian Journal of Basic and Applied Sciences, 3(3): 1696-1700.  Nautiyal A.R., Thapliyal A.P., Purohit A.N., 1985 - Seed viability. IV. Protein changes: Accompanying loss of viability in Shorea robusta. Seed Sci Technol, 13:83-86.  Pandey P.K., Goyal R.D., Parakash V., Katiyar R.P., Singh C.B., 1990 - Association between laboratory vigor tests and field emergence in cucurbits. Seed Sci Res, 18: 40-43. Saha R.R., Sultana W., 2008 - Influence of seed ageing on growth and yield of soybean. Bangla J Bot., 37:21-26. Siadat S.A., Moosavi A., Sharafizadeh M., 2012 - Effect of seed priming on antioxidant activity and germination characteristics of maize seeds under different aging treatments. Research Journal of Seed Science, 5(2): 51-62. Soltani E., Kamkar B., Galeshi S., Akram Ghaderi F., 2008 - The effect of seed deterioration on seed reserves depletion and heterotrophic seedling growth of wheat. Journal of Agricultural Sciences and Natural Resources, 15(1):13-17 (In Persian). Walters C., 1998 - Understanding the mechanisms and kinetics of seed aging. Seed Sci Res, 8:223-244.     

The changes of germination characteristics and enzyme activity of barley seeds under accelerated aging

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The changes of germination characteristics and enzyme activity of barley seeds under accelerated aging

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