Iranian Journal of Seed Research

This study was conducted to evaluate the effect of hydropriming and seed aging on germination and enzymatic properties of pinto bean under salinity stress as factorial based on a completely randomized design with four replications. Two groups of seeds (i.e., non-aged and aged seeds), two hydropriming treatments (i.e., hydro primed and unprimed seeds) and six salinity treatments (i.e., 0, 2, 4, 6, 8 and 10 dS/m) were the experimental factors. The results showed that the highest mean time and percentage of germination, plumule length and vigor were observed in the control (i.e., distilled water) and hydropriming treatments. Maximum root length and percentage of seedling water were obtained in the control (i.e., distilled water) and aged seed treatments. In addition, in terms of radicle dry weight, the highest amount was observed in salinity of 4 dS/m and non-aged hydro primed seeds. The highest plumule dry weight was observed in salinity of 6 dS/m and allometric index in salinity of 8 dS/m for non-aged seed and aged seed without hydropriming, respectively. An increase in the levels of salinity stress and aging the seeds increased the malondialdehyde and reduced the activity of germination, mean time and germination percentage, and seedling growth. Seed hydropriming reduced the peroxidation of the cell membrane and generally improved the speed and uniformity of germination, aged and natural seeds vigor under both salinity and optimum conditions. As a result, hydropriming can increase the tolerance of bean seeds to salinity at the germination stage and increase the germination capacity of stored seeds for cultivation.

Introduction: Indian Cheese Maker, an herbage plant, belongs to potatoes family and grows in areas such as Pakistan, Afghanistan, India and Iran. Given its medicinal properties, Indian Cheese Maker plays an important role in traditional Iranian medicine. Lack of dormancy is one of the most desirable agronomic characteristics of its seeds, which is necessary to achieve the highest amount of germination, emergence and plant establishment. Seed germination capacity of medicinal herbs is typically low, which is due to the presence of seed dormancy in these plants.

Material and Methods: This study was conducted to evaluate the effect of disinfection and pre-chilling on germination and enzymatic properties of different Indian cheese maker landraces. The experiment was conducted as a factorial based on a completely randomized design with three replications during 2015-16 at the Laboratory of the Department of Agronomy, Tarbiat Modares University. Two treatments consisting of seeds disinfected at two levels (no application and 30 min with hypochlorite solution 5%), two pre-chilling treatments (no application and 1 week pre-chilling) and four Indian cheese maker landraces (Fanuj, Khash, Saravan and Sarbaz) were the experimental factors. For the purpose of suitable pre-chilling to activate the germination enzymes, the seeds were placed in a coated container, on an aluminum foil with holes in it, without direct contact and close to distilled water at 4 °C. 25 seeds were placed in each sterile petri dish with Watten filter paper 42. Five ml of distilled water was added to each petri. After applying the treatments, the petri dishes were covered with parafilm and were placed in a germinator at 25 °C in the light for 14 days.

Results: The results showed that in the Fanuj, Khash and Saravan landraces, the highest values of final germination percentage, germination rate, mean daily germination and mean time germination were obtained during disinfection of 30 minutes and pre-chilling of one week. However, the Sarbaz landrace showed a reverse trend and indicated the highest values of these traits in non-application of seed disinfection and pre-chilling. In terms of the activity of germination enzymes, the highest values of α and β amylase (0.74 and 0.59 μmol/ml/min) were obtained in the Fanuj landrace with 30-minute disinfection with sodium hypochlorite and one-week pre-chilling.

Conclusion: According to the results, the Fenuj, Khash and Saravan landraces of Indian Cheese Maker showed positive reaction to disinfection with sodium hypochlorite for 30 minutes and pre-cooling for one week. The same treatments increased the properties and activity of germination enzymes. The Sarbaz landrace did not react positively to the treatments applied and reacted negatively in terms of the properties and activity of germination enzymes. The reason for this behavior in the Sarbaz landrace could be attributed to lower annual rainfall, as well as higher temperature, which causes the hardening of the seed’s cover and the increase in the values of germination inhibiting factors, creating seed dormancy, which allows it to survive hot and dry periods. Generally speaking, the use of sodium hypochlorite and pre-chilling can be recommended to break seed dormancy of most Indian Cheese Maker landraces.

Extended Abstract
Introduction: Medicinal herbs are of particular importance in the treatment and prevention of diseases. Indian Cheese Maker has strengthening, liver repair, anti-inflammatory properties and is useful in the treatment of bronchitis, asthma, wounds, neurological disorders such as Parkinson's and Alzheimer's. Evaluation of seed quality as a propagating organ and the most important input for crop production and medicinal products has a special place in seed production, control and certification. Studying germination and biological properties of seeds of medicinal plants and methods of breaking dormancy in them are among basic and primary studies of domestication of medicinal plants. In the meantime, scrubbing with abrasives changes the integrity of the seed shell and allows the seeds to be permeable to water and gases. The researchers stated that the dormancy of seeds containing inhibitory metabolic materials can be reduced by removing the seed shell through mechanical scarification and osmopriming. For this purpose, the effect of scarification and potassium nitrate on germination and enzymatic properties of Indian Cheese Maker was evaluated.
Material and Method: This study was conducted as factorial based on a completely randomized design with three replications during 2015-16 at the laboratory of Department of Agronomy, Tarbiat Modares University. Potassium nitrate solution (0, 0.5, 1 and 1.5 mg.l^-1 from KNO₃), scarification (un-use and scarification with soft sanding) and osmopriming durations (8, 16, 24 and 32 hour) were experimental factors. The experiment was performed on Indian Cheese Maker seeds, landrace of Khash. Petri dishes were placed in a germinator at 25 ° C and in full lighting for 14 days. In this experiment, germination rate and percentage of germination, mean of germination time and daily germination, seed vigority, alpha and beta amylase were measured.
Results: The results of the experiment showed that in scarification, the highest germination percentage (69.47%) was obtained by seed priming at a concentration of 1.5 mg.l^-1 potassium nitrate for 19 hours under abrasion. In scarification, germination rate increased at 16 and 32 hour, 0.62 and 1.17 No.day^-1 for each mg.l^-1 of potassium nitrate. The highest daily mean germination (0.15) was observed at 1.5 mg.l^-1 potassium nitrate and 24 hour time and decreased to 8 hours mean germination time (7.39 days) by reducing pretreatment time. Also, the highest mean germination time (9.35 days) was observed in 32 hours pretreatment with potassium nitrate and the highest mean germination time in non-scarification condition (9.13 days) and in scarification condition decreased with mean of germination time (8.04 days). The activity of alpha and beta-amylase germination enzymes was affected by different concentrations of potassium nitrate and scarification and at high concentrations of potassium nitrate the activity of these enzymes decreased.
Conclusions: In general, application of potassium nitrate osmopriming, by improving the activity of germination enzymes and increasing seed germination properties of Indian Cheese Maker, increased the activity of hydrolyzing enzymes in the endosperm of germinated seeds, which reduced the mean germination time, increased germination rate and germination percentage. In general, seed scarification with low concentrations of potassium nitrate at 16 to 24 hours is recommended for breaking seed dormancy of Indian Cheese Maker.

 
Highlights:

1. Germination rate and percentage of Indian Cheese Maker seed were monitored by osmopriming and scarification.
2. The role of α and β amylase germination enzymes in accelerating dormancy breaking of Indian Cheese Maker was studied.
3. Mean time and mean daily germination during the dormancy breaking process of Indian Cheese Maker were estimated.