Improved method of in vitro regeneration in Leucaena leucocephala — a leguminous pulpwood tree species

Abstract

Leucaena leucocephala is a fast growing multipurpose legume tree used for forage, leaf manure, paper and pulp. Lignin in Leucaena pulp adversely influences the quality of paper produced. Developing transgenic Leucaena with altered lignin by genetic engineering demands an optimized regeneration system. The present study deals with optimization of regeneration system for L. leucocephala cv. K636. Multiple shoot induction from the cotyledonary nodes of L. leucocephala was studied in response to cytokinins, thidiazuron (TDZ) and N(6)-benzyladenine (BA) supplemented in half strength MS (½-MS) medium and also their effect on in vitro rooting of the regenerated shoots. Multiple shoots were induced from cotyledonary nodes at varied frequencies depending on the type and concentration of cytokinin used in the medium. TDZ was found to induce more number of shoots per explant than BA, with a maximum of 7 shoots at an optimum concentration of 0.23 µM. Further increase in TDZ concentration resulted in reduced shoot length and fasciation of the shoots. Liquid pulse treatment of the explants with TDZ did not improve the shoot production further but improved the subsequent rooting of the shoots that regenerated. Regenerated shoots successfully rooted on ½-MS medium supplemented with 0.54 µM α-naphthaleneacetic acid (NAA). Rooted shoots of Leucaena were transferred to coco-peat and hardened plantlets showed ≥ 90 % establishment in the green house.

Abiotic stress induces change in Cinnamoyl CoA Reductase (CCR) protein abundance and lignin deposition in developing seedlings of Leucaena leucocephala

“…Seeds were treated as described by Shaik et al (2009). After 2 days in moist condition on shaker the seeds were transferred to tissue culture bottles containing ½ MS medium (Murashige and Skoog 1962) added with 1 % mannitol (w/v) and 200 mM NaCl for drought (Lipavska and Vreugdenhil 1996) and salt stress conditions, respectively.…”

Genetic Engineering of Phenylpropanoid Pathway in Leucaena leucocephala

“…Considering all above discussed reports, it can be suggested that our reports (Shaik et al, 2009) of improved method also have produced a consistent regeneration system for Leucaena which will be beneficial for the mass propagation and genetic transformation of Leucaena species. Lignin content in wood pulp adversely influences the quality of paper produced.…”

“…Liquid pulse treatment of the induced shoots with TDZ resulted in the improvement in the subsequent rooting. The plantlets regenerated in this manner showed more than 90% survival rate ex vitro when grown in coco-peat mixture (Shaik et al, 2009). In order to improve overall in vitro plantlet regeneration efficiency, attempts to propagate elite (cultivar K-8, K-636) and wild type varieties of Leucaena were made by supplementing the basal shoot induction media with puterscin.…”

“…The addition of cytokinins to the medium was found essential for multiple shoot induction. Leucaena cotyledonary nodes carried a high potential for rapid multiple shoot regeneration on medium containing lower concentrations of TDZ (0.05 or 0.23 µM) (Shaik et al, 2009). As multiple shoots originated from the mass of closely placed shoot initials of axillary meristems (Fig.…”

Multiplicação in vitro de Caesalpinia pyramidalis (Leguminosae)

“…Diferente do que foi observado neste estudo, no entanto, espécies lenhosas como Rauvolfia tetraphylla L. e Leucaena leucocephala (Lam.) de Wit apresentaram um alto número de brotos com a utilização de 5,0 (9,2 brotos/explante) e 0,23 µM (6,98 brotos/explante) de TDZ, respectivamente, adicionado ao meio de cultura (Faisal et al 2005;Shaik et al 2009). …”