In vitro Axillary Shoot Regeneration and Direct Protocorm-like Body Induction from Axenic Shoot Tips of Doritis pulcherrima Lindl.

Abstract

An efficient protocol for in vitro propagation of an important ornamental terrestrial orchid, Doritis pulcherima Lindl. through axillary shoot and direct protocorm-like body (PLB) formation from shoot tip explants derived from sixmonth-old axenic seedlings has been described. Shoot tips were cultured on modified nutrient medium of Knudson's C supplemented with 0.1% peptone and combination of various concentrations of NAA and BAP. The effect of NAA and BAP on axillary shoot formation, protocorm-like body induction and root regeneration from the explants was significant. The highest frequency of axillary shoot formation was recorded in the medium containing 2 mg/l BAP and the PLB production was higher in the medium containing 2 mg/l NAA. A higher concentration of BAP showed inhibitory effects on the axillary shoot formation and PLB induction. Efficient root regeneration was observed in low concentration of NAA. However, the profuse root formation was common in the PGR free medium. Rooted plantlets were hardened successfully through the stepwise acclimation protocol and platelets were finally established in the potting mixture containing small pieces of dead tree bark of mango, charcoal pieces and broken bricks in 1 : 2 : 1 ratio.

In vitro Direct Regeneration from Node and Leaf Explants of Phalaenopsis cv. ‘Surabaya’

“…The effect of NAA and BAP on axillary shoot formation, protocorm-like body induction and root regeneration of Doritis pulcherrima orchid was significant. Among the different combinations, 1 mg/l NAA and 2 mg/l BAP were found effective in shoot multiplication (Mondal et al 2014). The highest number of shoots (15.3) was obtained from MS supplemented with 4 mg/l BA and 1 mg/l NAA (Balilashaki et al 2014).…”

“…1e). Mondal et al (2014) regenerated single shoots when cultured in both Knudson's C (1946) (KC) + peptone and KC media supplemented with low concentrations of NAA (0.5 -1 mg/l). Efficient root regeneration was observed in low concentration of NAA.…”

“…Since the conventional breeding is slow and difficult, tissue culture methods are the way for clonally mass propagation of commercial species. Many in vitro culture protocols have been developed for Phalaenopsis regeneration utilizing flower stalk buds, stem nodes (Tokuhara and Mii 2001, Balilashaki et al 2014, Kosir et al 2004) entire shoots, shoot tips (Griesbach 2002, Talukder et al 2003, Hong et al 2010, Pant and Thapa 2012, Mondal et al 2014, leaf tissues/segment (Nayak et al 1997, Park et al 2002, Chen and Chang 2004, Chen and Chang 2006, Mayer et al 2010, Niknejad et al 2013 or root tips culture (Park et al 2003). PLBs which can be induced directly from various explants are important in orchid regeneration.…”

In vitro regeneration from protocorms in Dendrobium aqueum Lindley – An imperiled orchid

“…The role of BAP in plantlet production from PLBs of Dendrobium formosum , reported very effective in terms of height and highest number of shoot and root formation [32], however in Dendrobium nobile [34], Dendrobium huoshanense [22] and Doritis pulcherrima [29] BAP was found inhibitory to the conversion of protocorms into plantlets and root formation. Similar inhibitory response with very lesser multiple shoots and stunted growth was observed on medium containing BA in D. aqueum .…”

<b>Determination of endogenous IAA and carbohydrates during the induction and development of protocorm-like bodies of <i>Cattleya tigrina</i> A. Richard

“…PLBs are globular structures named after their similarity with zygotic origin embryos (protocorms) (Arditti, 2008). These structures can be directly induced from meristematic shoots (Mondal, Aditya, & Banderjee, 2013), flower stalks (Chen & Chang, 2000), leaf segments (Khoddamzadeh et al, 2011;Deb & Pongener, 2013) or indirectly, with an intermediate callus stage (Jainol & Gansau, 2017).…”