Effect of Temperature and Plant Growth Regulators on Seed Germination Response of Oroxylum indicum-A High Value Threatened Medicinal Plant of Sikkim Himalaya

Oroxylum indicum is an integral component of Indian Ayurvedic medicine system. Owing to depletion of its natural populations, the plant is facing threats of extinction. Different plant growth regulators (viz. Benzyl amino purine, Indole-3-acetic acid, Gibberellic acid) and temperatures (cold and hot water) were used to improve seed germination in O. indicum. Cold water treatment had significantly improved the seed germination as compared to control, hot water treatment and tested plant growth regulators. Cold water at 4 °C for 24h was found to be optimum, which resulted in to more than 80% seed germination response. Here, it is the first time we have described the seed germination requirement of Oroxylum indicum, using growth hormones and temperatures. The study suggested that the seed germination and seedling growth of Oroxylum can be improved by using simple and economic method.