Effects of Hydro and Osmopriming on Germination and Emergence of Asafoetida (Ferula assa-foetida L.)
Document Type : Original Article
Authors
1 Research Assistant and MS Graduate / Agriculture and Natural Resources Research and Training Center of Soyth Khorasan, Islamic Azad University of Birjand, Iran
2 Associate Professor, Faculty of Agronomy and Plant Breeding, Islamic Azad University, Birjand, Iran
3 Senior Research Fellow / the Institute of Forest and Range, Tehran, Iran
Abstract
Introduction: Asafetida (Ferula assa-foetida) is a medicinal plant belonging to the family of Apiaceae. The economically important part of the herb is the resin known as Asafetida gum which is extracted by cutting the apex. Currently almost 100% of the gum in the market is fully dependent on natural ecosystems. High demand of this species for pharmaceutical industry has made a unique opportunity for farmers to initiate and expand the plant cultivation in arable lands. Issue in seed germination of asafetida is the first step of the domestication process aimed to be resolved. To address the issues, a laboratory and glasshouse research project using a range of osmo-hydropriming treatments was conducted in Mohammadiah Station of Agriculture and Natural Resources Research and Training Center, Southern Khorasan, Iran in 2014.
Materials and methods: The laboratory experiment was composed of six treatments (osmopriming with CaCl2 at osmotic potentials of -1 and -2 MPa and with KH2PO4 at -1 and -2 MPa, hydropriming with distilled water and unprimed seeds as control) in four replications based on a Completely Randomized Design. While the glasshouse experiment was set using 3 priming treatments selected from the lab phase results (hydropriming, osmopriming with CaCl2 at -1 MPa and with KH2PO4 at -2 MPa) and unprimed treatment seeds as control. The seeds were treated in glassy beakers containing 150 mlof priming solution (volumetric ratio of solution to seeds was 5) for 12 hours (Van’t Hoff, 1887). Then they were washed with distilled water three times and dried at 20°C in an infected-free medium in laboratory for 12 hours. In lab experiment Petri dishes with the diameter of 10 cm containing two filter papers were used for germination. So 7 ml distilled water was first added to Petri dishes and 15 seeds were placed. They were then kept in a germinator at 14°C and light period of 12 hours for one month. In control treatment, the seeds were placed in Petri dishes after wet chilling without priming. The recorded traits at laboratory phase included germination percentage, germination rate, mean germination time, seedling dry weight, seed vigor, seedling length. In the glasshouse experiment, the pots with the diameter of 10 cm were filled by fine sands and 15 seeds were placed at the top and covered with a one centimeter depth of sand. To make sure that the seedlings have access to nutrients, the pots were watered by hydroponic nutrient solution(Hoagland and Arnon, 1950) once in 3 watering events. In the glasshouse trial, the following traits were recorded: Emergence percentage (EP), emergence rate (ER), seedling dry weight (DW), vigor index (VI), seedling length (SL).
Results and discussion:In both experiments the results showed that priming increased germination percentage as compared with control. Among the studied priming treatments at the laboratory, priming with distilled water, KH2PO4 -2 MPa and CaCl2 -1 MPa had the greatest effect on increasing germination percentage of Asafetida seeds. They had significant effects on germination rate as well especially at the seed lot treated by CaCl2 at -1 MPa, reaching to the maximum level of 0.099 (1/day). These three treatments were also successful at glasshouse trial having higher significant emergence percentage and emergence rate than control. The seed vigor of asafetida received high level of significant positive outcomes with hydroprime and osmoprime (CaCl2 at -1 MPa) in which hydroprime achieved the highest vigor index of 916 at lab experiment. At glasshouse experiment all the priming treatments significantly increased the vigor index and seedling length. Khalil et al. (1997) related the increase in the length of seedling, shoot and root to the increase in germination rate influenced by priming. Seedling dry weight also showed a positive response to the priming treatments. The dry weight was highest (0.1 gram) in the two osmoprime treatments (CaCl2 -1 MPa and KH2PO4 -2 MPa) and was lowest in the other two treatments (control and osmoprime KH2PO4 -1 MPa) with 0.08 and 0.075 gram respectively. In literature, the increase in dry weight is more attributed to the higher growth rate incurred in priming treatments.
Cellular and molecular studies showed that priming increase seed capability in improving DNA replication, stimulating RNA activities, enhancing protein synthesis and hormone driven germination. Therefore, when the treated seeds are placed in germination conditions, they show significantly higher germination characteristics than control (Azarnivand et al., 2010). Moreover priming increases the enzymatic activities of the seeds resulted in per-oxidation of lipids resulted in repairing some of the damaged seeds. For instance, Jeng and Sung (Jeng and Sung, 1994) found that free radicals were destroyed by enzymes that were accumulated by higher water absorbed during priming in Groundnut seeds. The overall outcome here showed that seed priming can play an important role to improve seed germination and emergence in Asafetida. Meanwhile between the treatments, hydropriming and osmopriming with CaCl2 at -1 MPa showed to have full significant effects on the traits at both laboratory and glasshouse experiments. Nevertheless as hydropriming uses distilled water instead of chemicals, it will have no negative impact on environment. For this reason in some regions it may be recommended to use hydropriming rather than osmopriming.
Materials and methods: The laboratory experiment was composed of six treatments (osmopriming with CaCl2 at osmotic potentials of -1 and -2 MPa and with KH2PO4 at -1 and -2 MPa, hydropriming with distilled water and unprimed seeds as control) in four replications based on a Completely Randomized Design. While the glasshouse experiment was set using 3 priming treatments selected from the lab phase results (hydropriming, osmopriming with CaCl2 at -1 MPa and with KH2PO4 at -2 MPa) and unprimed treatment seeds as control. The seeds were treated in glassy beakers containing 150 mlof priming solution (volumetric ratio of solution to seeds was 5) for 12 hours (Van’t Hoff, 1887). Then they were washed with distilled water three times and dried at 20°C in an infected-free medium in laboratory for 12 hours. In lab experiment Petri dishes with the diameter of 10 cm containing two filter papers were used for germination. So 7 ml distilled water was first added to Petri dishes and 15 seeds were placed. They were then kept in a germinator at 14°C and light period of 12 hours for one month. In control treatment, the seeds were placed in Petri dishes after wet chilling without priming. The recorded traits at laboratory phase included germination percentage, germination rate, mean germination time, seedling dry weight, seed vigor, seedling length. In the glasshouse experiment, the pots with the diameter of 10 cm were filled by fine sands and 15 seeds were placed at the top and covered with a one centimeter depth of sand. To make sure that the seedlings have access to nutrients, the pots were watered by hydroponic nutrient solution(Hoagland and Arnon, 1950) once in 3 watering events. In the glasshouse trial, the following traits were recorded: Emergence percentage (EP), emergence rate (ER), seedling dry weight (DW), vigor index (VI), seedling length (SL).
Results and discussion:In both experiments the results showed that priming increased germination percentage as compared with control. Among the studied priming treatments at the laboratory, priming with distilled water, KH2PO4 -2 MPa and CaCl2 -1 MPa had the greatest effect on increasing germination percentage of Asafetida seeds. They had significant effects on germination rate as well especially at the seed lot treated by CaCl2 at -1 MPa, reaching to the maximum level of 0.099 (1/day). These three treatments were also successful at glasshouse trial having higher significant emergence percentage and emergence rate than control. The seed vigor of asafetida received high level of significant positive outcomes with hydroprime and osmoprime (CaCl2 at -1 MPa) in which hydroprime achieved the highest vigor index of 916 at lab experiment. At glasshouse experiment all the priming treatments significantly increased the vigor index and seedling length. Khalil et al. (1997) related the increase in the length of seedling, shoot and root to the increase in germination rate influenced by priming. Seedling dry weight also showed a positive response to the priming treatments. The dry weight was highest (0.1 gram) in the two osmoprime treatments (CaCl2 -1 MPa and KH2PO4 -2 MPa) and was lowest in the other two treatments (control and osmoprime KH2PO4 -1 MPa) with 0.08 and 0.075 gram respectively. In literature, the increase in dry weight is more attributed to the higher growth rate incurred in priming treatments.
Cellular and molecular studies showed that priming increase seed capability in improving DNA replication, stimulating RNA activities, enhancing protein synthesis and hormone driven germination. Therefore, when the treated seeds are placed in germination conditions, they show significantly higher germination characteristics than control (Azarnivand et al., 2010). Moreover priming increases the enzymatic activities of the seeds resulted in per-oxidation of lipids resulted in repairing some of the damaged seeds. For instance, Jeng and Sung (Jeng and Sung, 1994) found that free radicals were destroyed by enzymes that were accumulated by higher water absorbed during priming in Groundnut seeds. The overall outcome here showed that seed priming can play an important role to improve seed germination and emergence in Asafetida. Meanwhile between the treatments, hydropriming and osmopriming with CaCl2 at -1 MPa showed to have full significant effects on the traits at both laboratory and glasshouse experiments. Nevertheless as hydropriming uses distilled water instead of chemicals, it will have no negative impact on environment. For this reason in some regions it may be recommended to use hydropriming rather than osmopriming.
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