Leucine and spermidine enhance shoot differentiation in cucumber (Cucumis sativus L.)

Enhanced numbers of multiple shoots were induced from shoot tip explants of cucumber. The effects of amino acids (leucine, isoleucine, methionine, threonine, and tryptophan) and polyamines (spermidine, spermine, and putrescine) along with benzyladenine (BA) on multiple shoot induction were investigated. A Murashige and Skoog (MS) medium containing a combination of BA (4.44 mu M), leucine (88 mu M), and spermidine (68 mu M) induced the maximum number of shoots (36.6 shoots per explant) compared to BA (4.44 mu M) alone or BA (4.44 mu M) with leucine (88 mu M). The regenerated shoots were elongated on the same medium. Elongated shoots were transferred to the MS medium fortified with BA (4.44 mu M), leucine (88 mu M), and putrescine (62 mu M) for root induction. Rooted plants were hardened and successfully established in soil with a 90% survival rate.