Orientation of Seed Explant Significantly Enhances Shoot Regeneration Potential in Pigeonpea (Cajanus Cajan L.). Role of Ethylene and Methane in Relation to Regeneration Response

摘要

In pigeonpea (Cajanus cajan L.) shoot differentiation was observed to be influenced by type, age and specific orientation of the seed explant. 4 day old seed explant in which both radicle and plumule were excised (type D explant) was observed to be superior to the other types of seed explants. Inoculation of type D explant in a specific orientation (reverse orientation) i.e., keeping the plumule side portion in contact with the shoot bud induction medium gave better shoot bud Induction response. Among various benzyl adenine concentrations tested, maximum shoot bud induction was observed at 2.0 mg dm~(-3) benzyladenine concentration. Better shoot bud development was observed in Gamborg medium supplemented with benzyladenine 0.1 mg dm~(-3) and naphthalene acetic acid 0.01 mg dm~(-3). Ethylene and methane evolution suggest that certain minimum amounts of ethylene and methane are required for both shoot bud induction and development. The desired ethylene methane ratio for better response. Elongating shoots appears to evolve more methane. Shoots with regenerated roots were cultured in Hoagland solution for 25 days before transferring to vermiculite/soil. 80% of the regenerants developed into morphologically normal and fertile plants. This type of specific RO type orientation effect for shoot bud induction particularly with reference to seed explants of pigeonpea was not reported.