EFFECT OF SOME CHEMICAL TREATMENTS ON SEED GERMINATION AND DORMANCY BREAKING IN AN IMPORTANT MEDICINAL PLANT OCHRADENUS ARABICUS CHAUDHARY, HILL C. & A.G. MILL.

Abstract

The seeds of Ochradenus arabicus, a medicinally important plant endemic to Saudi Arabia, become dormant and thus do not germinate easily. An attempt was made to improve seed germination and break the dormancy. The seeds were subjected to 2 plant growth regulators [GA3 (25-500 µM) and BAP (25-350 µM)] and two chemicals (KNO3 and thiourea) at 0.1-0.5% concentrations. Germination of seed was recorded after 20 days of sowing the seed in different treatments. Maximum germination was obtained by GA3 at 100µM, however, decline in germination was observed at higher concentrations of GA3. The germination of seeds was found to be improved upon storage for 6 and 12 months. In general, all treatments showed increased germination compared to that of control. This might have occurred due to the slow release of an inhibitory dormancy factor with different exogenously applied treatments. It was also interesting to note that the asynchronous germination lasted to 25 more days. This may be a survival adaptation of O. arabicus to harsh climatic conditions prevalent in a desert.