55 GEN. APPL. PLANT PHYSIOLOGY, 2005, 31(1-2), 55-63 RESPONSE OF GERMINATING SEEDS OF CICER ARIETINUM TO 28-HOMOBRASSINOLIDE AND/OR POTASSIUM Barket Ali, S.Hayat* and A.Ahmad Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh- 202002, India Received: January 09, 2004 Summary. The involvement of ionic channel/s in signal transduction and the amplification of phytohormones induced impact on the processes leading to seed germination provoked us to undertake the present study. Seeds of Cicer arietinum (L.) cv. Avarodhi were soaked in the aqueous solutions of 28- homobrassinolide (HBR) and/or K + , for a limited period, and subsequently transferred to distilled water, for the rest of the germination period. The seeds were sampled 24, 36 and 48 hours after soaking and were analyzed for rela- tive water content, activity of nitrate reductase and for the contents of nitrate and total protein, as well. HBR treatment caused highest values of all the characteristics, except the nitrate content. Among the treatments, HBR (10 -8 M), alone or in combination with potassium (12 μM), proved as best in activating the observed characteristics. Keywords: Germination, Relative water content, Nitrate reductase activity Abbreviations: BR-Brassinosteroid, HBR-28-homobrassinolide, NR-Nitrate reductase * Corresponding author; e-mail: shayat@lycos.com