Assessment of Germination Characteristics and α and β Amylase Activity of Indian Cheese Maker (Withania coagulans) Seed in Response to Scarification and Potassium Nitrate

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.

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.

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.

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. 

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