عنوان مقاله [English]
Introduction: The aim of medicinal plant storage is to preserve qualitative and quantitative properties of active substance. Carum copticum fruits (Zenyan in Persian) were used for its therapeutic effects. Seed storage condition after harvest till to extraction time is not suitable in our country and the major part of seed quality deteriorates during the storage period. So, the loss of seed qualitative and quantitative characteristics will increase during unsuitable storage condition. Appropriate storage conditions and management preserve seed active substance, seed viability and vigor for long periods by reducing the rate of seed deterioration. Optimal seed storage can be achieved by modifying the environment around the seeds. Numerous storage systems have evolved over the years for post harvest preservation of crop seeds. The aim of this study is to evaluate the effect of various storage conditions and storage time on essential oil percentage and germination factors in C. copticum seeds during the storage period. The results of this research will be used for optimum storage of these seeds to better preserve their quality.
Materials and Methods: In order to investigate the effects of storage conditions (packaging materials and temperature) and storage time on quality of C. copticum stored seeds, a split-plot factorial arranged in a randomized complete block design with three replications is performed in Faculty of Agriculture at Ferdowsi University of Mashhad during 2013 and 2014.Tukey's range test was performed to determine the significant difference between treatments. The calculations were conducted by JMP 8 software. Temperature) at two levels: 20±3°C and 30±3°C( as main plots and packaging materials (at six levels: paper, polyethylene, aluminum foil under vacuum condition, Polyethylene-polyamide packages under vacuum condition, Polyethylene-polyamide packages with a gas composition of [98%N2 + 2%O2] and [90%N2 +10%O2] ) and storage periods (at four levels: 0, 3, 6 and 9 months) as sub plots were considered. Seed samples were taken randomly from each package at four times period. Essential oil percentage, seed weight, gas composition in packages with modified atmosphere and seed germination factors (seed germination percentage (SGP), germination rate (GR), mean germination time (MGT), and germination Index (GI)) were evaluated during this nine months Storage.
Results and Discussion: The highest weight loss was 2/43% in the paper bags stored at 30°C at the fourth to sixth months especially in the fifth month. Aluminum foil package under vacuum condition stored at 30°C had the lowest weight and minimum weight changes during nine months of storage, so it was the best packages compared to others. The results show that Polyethylene-polyamide packages and Aluminum foil packages under vacuum condition are almost impermeable to air and moisture. Increasing weight at 20°C may be due to accumulation of water vapor from the respiration during early period of storage. Seed germination test provides an indication about seedling vigor as well as performance of seed in the field. In most cases, performance relates to the ability of seeds to germinate and produce a seedling that will emerge from the soil and development into a healthy vigorous plant. Packages with different combinations of gas (2% and 10% oxygen) at 30°C,aluminum foil under vacuum condition and Polyethylene-polyamide packages with a gas composition of [98%N2 + 2%O2] at 20°C were packages with higher germination percentage after nine months storage. Based on this results, it appears that packaging materials and storage temperature did not show any significant difference on essential oil percentage and further changes in the amount of oil related to duration of storage. Kumar et al. (2013) showed that the essential oil content and composition were affected by harvest time and storage conditions. Kazaz et al. (2009) investigated the effect of different storage temperatures (0◦C and 3◦C) and durations (7, 14, 21 and 28 days) on oil yield and essential oil components of oil rose (Rosa damascena Mill.). Their results showed that the effect of storage temperatures on oil content were not significant whereas the effect of storage duration was significant and it was similar to our results.
Conclusion: Essential oil percentage as the most important property of Carum copticum and germination percentage decreased significantly with increasing of storage period. Finally, results show that Polyethylene-polyamide packages with a gas composition of [98%N2 + 2%O2] and [90%N2 +10%O2] in 9 months storage time and 30±3°C storage temperature preserve qualitative properties better than other conditions. Whereas, aluminum foil package under vacuum condition and 20±3°C storage temperature are recommended for 6 month storage time.