Ethylene inhibitors promote in vitro regeneration of cowpea (Vigna Unguiculata L.)

Ethylene is a plant growth regulator that is known to influence in vitro mo rphogenesis. This study investigated the effects of three ethylene inhibito rs, silver nitrate (AgNO3), 2,5-norhornadiene, anti cobalt chloride (CoCl2) , on the regeneration of cowpea from cotyledon explants. Significant increa ses in the percentage of regeneration occurred as a result of adding either 50 mu M AgNO3 or 100 mu M 2.5-norbornadiene. The number of shoots produced per explant was enhanced by adding 25 mu M CoCl2, or 100 mu M norbornadien e. Maximum shoot elongation was obtained with 25 mu M of either CoCl2 or no rbornadiene. The effect of the duration of exposure to AgNO3, was also dete rmined. The greatest percent regeneration was obtained with the addition of 60 mu M AgNO3 either to both the initiation and regeneration stages, or to only the regeneration stage. The promotive effects on organogenesis in res ponse to ethylene inhibitors: suggests an important role for ethylene in th e process of in vitro morphogenesis of cowpea and may contribute to its nor mally low regeneration frequency.