DETERMINATION THE CONDITIONS IN CULTURE AND TUBERIZATION IN VITROOF TORPEDO GRASS (PANICUM REPENS L.)

Abstract

Torpedo grass (Punicum repens L.) is a weed species usually found on different environmental conditions, easily infected in vitro culture. Sterilization of samples could be made with calcium hypochlorite 10% solution for 15 to 25 minutes or HgCl2 0,1% for 10 to 20 minutes. Adding Tween 20 (0,15% v/v) in the calcium hypochlorite solution or HgCl, solution increases the efficacy of sterilization. A solution of HgCl2 0,1% plus Tween 20 (0,15% v/v) during 15 minutes sterilization goes a high result. The Murashige-Skoog's salts culture medium complemented Morel and Wetmore medium's vitamins, 4% sucrose and 2 mg/1 IBA is used. Root formation is good with this IBA concentration. In our first experiment of culture in vitro, using the culture medium supplemented with 25 mg/l AlCl3 plantlets grow well. The samples should be taken from the stem instead of the tuber or the rhizome. Torpedo grass tuberization succeeds only under complete darkness at 27°C in the culture medium containing plant growth substances. The tuberization is not induced in the light at 27°C or in dark at 22°C although the culture medium have been supplemented with plant growth substances. The full strength Murashige-Skoog's salts are not effective for Torpedo grass tuberization. The tuberization culture medium is a haft strength Murashige-Skoog's salts complemented Morel and Wetmore medium's vitamins, 8% sucrose and plant growth substances. Gibberellin completely inhibited whereas cytokinin and ABA induced tuberization. The tuberization rate is high (76%) with BA 20 mg/l. When NAA, BA and ABA are mixed at concentration 0,4:20:0,3 mg/1, the rate of tuberization is the highest (91%). The role of plant growth substances on the tuberization is also discussed in this paper.