A note on in vitro callus induction and shoot development in Paphiopedilum druryi (Bedd.) Stein – a Critically Endangered and Horticulturally Promising Orchid

Abstract An efficient pilot protocol for callus induction and shoot development was established in a narrow endemic and Critically Endangered terrestrial orchid Paphiopedilum druryi (Bedd.) Stein. 27.78% green compact callus was produced from stem TCLs on half-strength MS medium (½ MS). The callus remained viable for 2 months and then turned to yellow and brown. Axillary shoot explants cultured on ½ MS medium supplemented with 10X (MS) vitamins, 170 mg L⁻ ¹ NaH₂PO₄, 0.5% PVP, 2.0 mg L⁻ ¹TDZ with 0.1 mg L⁻ ¹1-naphthaleneacetic acid (NAA) favoured shoot development on 50% explants up to 3 months of culture period. Subsequent symbiotic cultures of the shoots with Tulasnella calospora produced new leaf and root tip, which were successfully recovered to asymbiotic culture after sterilization. These pilot protocols can be applied on large scale with modification following wider screening of physical and chemical factors for improved results.