Effect of nitrates (potassium nitrate and ammonium nitrate) 2-iP and GA3 on in vitro shoot multiplication in Gymnema sylvestre R.Br.

Abstract

AIM: Gymnema sylvestre R.Br. (family-Asclepiadaceae.) is a medicinal plant of immense pharmaceutical value. The species is threatened with extinction due to its indiscriminate collection as raw material for pharmaceutical industry, to manufacturing drugs for diabetes, asthma, eye complaints, etc. A rigorous attempt has been made for development of in vitro shoot multiplication for this species. METTHODS: Aseptic cultures were established on Nitsch and Nitsch, 1969 Medium (NN) containing 2.5 µM BA (N6-Benzyladenine). Tow experiments were conducted to study the effct of Nitrates (potassium nitrate and ammonium nitrate), 2-iP (N6-2-isopentyl) and GA3 Gibberellic acid on in vitro shoot multiplication of Gymnema sylvestre. RESULTS: The results of the study revealed that potassium nitrate and ammonium nitrate proved optimum for in vitro shoot multiplication, resulting in additions of 1.0x NH4NO3 increases shoot number per explant 34% and 30%. 2.0x KNO3 enhanced shoot number per explant by 30% at 15 days and 33% at 30 days after inoculation. 1.0x KNO3 had 26.08% higher value for node number per shoot that in 1.5x NH4NO3. Different strengths of NH4NO3 and KNO3 significantly influenced node number per explant. 1.0x NH4NO3 enhanced node number per explant by 54% and 40% at 30 days after inoculation. Node number per explant recorded in 2.0x KNO3 was 37 % and 50 % higher than that in 0.5x KNO3 at stages of sampling. Effect of GA3 and its interaction with 2-iP was found to be significant for shoot number per explant at 15 days after inoculation. Shoot number per explant was 23% higher in GA3 at 0.60 µM than GA3 at 0.15 µM. The enhancement recorded in 0.30 µM GA3 with 1.50 µM 2-iP for shoot number per explant was 72% more than that in 0.15 µM GA3 with 1.50 µM 2-iP. Various doses of GA3 significantly influenced node number per shoot at the stages of sampling. GA3 at 0.45 µM enhanced node number per shoot by 11.11% and 11.40 in comparison to GA3 at 0.15 µM at 15 and 30 days after inoculation. Node number per explant was 30% more in comparison to GA3 at 0.15 µM. The highest dose of GA3, i.e. 0.60 µM facilitated maximum shoot length but was statistically equaled by GA3 at 0.30 – 0.45 µM. The lowest dose of GA3, i.e. 0.15 µM produced significantly lowest shoot length. GA3 at 0.60 µM recorded 35% more shoot length than GA3 at 0.15 µM. CONCLUSION: An efficient technique for in vitro shoot multiplication of Gymnema sylvestre has been developed. The procedure offers a potential system for improvement, conservation and mass propagation using explants derived from in vitro raised shoot of Gymnema sylvestre.