Regeneration of plantlets from leaf disc cultures of rosewood: control of leaf abscission and shoot tip necrosis

Abstract

A method for mass production of rosewood ( Dalbergia latifolia Roxb.) trees through leaf disc organogenesis was developed and standardized. Compact callus was initiated from mature leaf discs on Murashige and Skoog (MS) basal medium supplemented with 1.0 mg 1 −1 2,4-dichlorophenoxy acetic acid (2,4-D), 5.0 mg 1 −1 α-naphthaleneacetic acid (NAA), 1.0 mg 1 −1 6-benzylaminopurine (BAP) and 10% coconut water (CW). High frequency (15–20 shoots/g callus) regeneration of shoot bud differentiation was obtained on MS (3/4 reduced major elements) or Woody Plant Medium (WPM) or modified Woody Plant Medium (mWPM) supplemented with BAP (5.0 mg 1 −1) and NAA (0.5 mg 1 −1). Leaf abscission and shoot tip necrosis was controlled using mWPM. About 90% of the excised shoots were rooted in the mWPM supplemented with 2.0 mg 1 −1 β-indolebutyric acid (IBA) and 1.0 mg 1 −1 caffeic acid. The in vitro-raised rooted plantlets were hardened for successful transplantation to soil. The transplanted plants were exposed to various humidity conditions and 80% transplant success was achieved. The in vitro-raised leaf-regenerated plants grew normally and vigorously in soil.