Seed germination characteristics of ratanjot, Arnebia euchroma (Royle) I.M. Johnston, a threatened medicinal plant species from cold desert of Spiti (Himachal Pradesh, India): Improvement by Ga₃, sodium nitroprusside and proline

Arnebia euchroma (Royle) I. M. Johnston, commonly known as Ratanjot, is a threatened, medicinally important plant species. It is used to cure an array of ailments including cough, lung problems, hair fall, dandruff and menorrhagia etc. The roots are also used to colour food preparations by the inhabitants of Lahaul and Spiti. We have characterized the seed germination aspects of A. euchroma from the cold desert region of Spiti (Himachal Pradesh, India) in W. Himalaya with an emphasis on achieving improved seed germination performance through pre-treatment of seeds with GA₃ and certain physico-chemical effectors. The freshly harvested seeds exhibited poor germination (30%). Of the tested effectors, GA₃ was most effective in promoting the seed germination. Besides, sodium nitroprusside (SNP) and proline proved nearly as effective as GA₃; these effectors have not been commonly employed for germination improvement in high altitude medicinal plants. KNO₃ was marginally promotory but acid scarification of seeds had virtually no effect. Analyses of certain biochemical parameters such as free proline contents, total phenolic contents, MDA contents and α-amylase activity provided insight into the mechanism of stimulation of seed germination by the stated effectors. The findings have implications for the conservation and cultivation of A. euchroma.