Legume Research, 19 (1) : 1-6, 1996. P LANT GROWTH REGULATORS IN INDUCI NG DIFFERENTIATION IN EXPLANT CULT URES OF CHICKPEA (CICER A RIETINUM L.) R. Chand ra, Anjali Chathrath, Vijay Paul , Sangeeta Khetarpal and Raghuvccr Polisetty D ivision of Plant Physiology, Indian Agricu ltural Research Institute, New Dclhi - 110 012, Indi a ABSTRACT Rapid increase in dry weight, increase in nitrogen and protein content and negligi- ble amounts of ethylene evolution were found to be related to differentiation of multiple shoot s in cultures of seedli ng shoot tips of chickpea. Slow growth rate, low per cent nitrogen in cultures of segments of seedling hypocotyl lead only to callus formation . INT RODUCTION The role of plant gro wth regul ato rs (PG R) in different iati o n has been well documented (Kartha et al., 1981 and Altaf Ahmed, 1986). None the less the actual role played by pla nt growth regulator is not fully understood (Evans, 1984). Concent rat ion as well as sensitivity of the tissue to PGR regulate plant development (Trevawas and Clelan d. 1983). Though protocols for regeneration through organogenesis (Barna and Wakhlu, 1994) or embryogenesis \Kumar et al. , 1994) were available, the physiological and biochem ical basis for differen- t iation is not de fi ned so far. Beca use of this much of th e rep orted work is not reproducible. Our research is directed to understand the differentiation process in chickpe a in terms of growth, nitrogen, protein conte nt and evolution of ethylene. In the p resent work we have assessed the inductive effect of five PGRs on differentiation of seed ling explants of chickpea, variety BG-256. The changes in differentiating tissues whic h ar e induced by PGRs as compare d to those tissues which failed to get induced were studied. MAT ERIAL AND METHODS Seeds of chick pea var. BG-256, surface sterilised with 0.1% mercuric chloride were germinat ed on filter paper boat s floated on sterile wa ter in culture tu bes. Seedling shoot tips (St), cotyledonary node (Cn) and hypocotyl (Hyp) segments (0.5 - l cm long ) were cultu red on (Mu rash ige and Skoog 1962) medium supplemented with desired PGRs (C han dra et al., 1993). The cultures were maintain ed at 25°C temperat ure and 900 lux light intensity. Each experi ment IAA = In dole Acetic Acid ; IBA =[ndole Butyric Acid; 2,4-D = 2,4 Dichl orop henoxy Acetic Acid; K n --Kmeti n: N A A= Nap hthalene Acet ic Acid; BAP =Benzyl Aminopurine; PIM= Plant Induction Medium; CIM=Callus Induction Medium; SfMe-Shoot Induction Medium, DA C =D. IYs After Culture; G ro wth Reg ulato r .