Abstract
Experiments were conducted in Tissue Culture Laboratory and net house of the Department of Crop Botany, BAU, Mymensingh from April 2009 to December 2011 to develop in vitro seedling/plantlet production protocols in six orchids. Culture temperature was 25 ± 1 °C and light intensity was 30-35 μmol m-2s-1. In Aerides odorata and Rhynchostylis retusa, seed derived in vitro seedling production and in Mokara Orange, Mokara Die Heard Red, Vanda tessellata and Aerides lawrenceae, PLBs derived plantlet production were studied. In Aerides odorata, 1/2 MS medium supplemented with 20 g 1-1 sucrose, 100 ml 1-1 rice extract was the most suitable for seed germination and NP medium with same energy supplement and 2.0 mg 1-1 NAA was the best for protocorm multiplication. For seedlings growth in vitro, NP medium supplemented with 30 g 1-1 sucrose and 100 ml 1-1 coconut water (CW) was the most effective, but for growth of seedlings in pot, fertilizer spray (3.0 g 1-1 @ N:P:K=20:10:15) with 1.0 mg 1-1 BA + 1.0 mg 1-1 NAA was the best. In Rhynchostylis retusa, suitable medium and supplements were same as Aerides odorata for seed germination and NP medium with 100 ml 1-1 CW was the best for protocorm multiplication. For seedlings growth in virto, 50 ml 1-1 banana extract (BE) was effective in 1/2 MS medium. Tissue paper was the best as substrate for acclimatization of seedlings. Fertilizer spray (2.5 g 1-1 at the ratio of N:P:K =30:10:10,) with BA and NAA at 1.0 mg 1-1 each was the best for seedlings growth in pot. In Mokara Orange, 2 MS supplemented with 50 ml 1-1 CW, 1.5 mg 1-1 BA 1.0 mg 1-12, 4-D and 0.5 mg l-1 NAA were the best for PLBs induction from shoot tips and same medium with 1.0 g 1-1 MES, 2.0 g F 1 peptone, 1.0 mg 1-1 TDZ and 0.25 mg 1-1 NAA was the most effective for PLBs multiplication. For the growth of plantlets in vitro, MS medium with 30 g 1-1 sucrose, MES and charcoal at 1.0 g 1-1 each, 2.0 g 1-1 peptone and 100 ml 1-1 potato extract (PE) was the best. In Mokara Die Heard Red, NP medium with 1.5 g 1-1 peptone, 100 ml 1-1 CW, 1.0 mg 1-1 TDZ, 1.0 mg 1-12, 4-D and 0.5 mg 1-1 NAA was recommendable for PLBS induction from shoot tips. For PLBs multiplication, same medium with 0.15 g 1-1 L-glutamine, 1.0 g 1-1 peptone, 100 ml 1-1 CW, 2.0 mg 1-1 BA, and 0.5 mg 1-1 NAA were the best. The same medium with 1.0 g 1-1 charcoal, 0.5 mg 1-1 BA and 75 ml 1-1 CW was the most suitable for in vitro growth of plantlets. For plantlets acclimatization tissue paper was the best as substrate. Fertilizer spray (3 g 1-1 @ N:P:K= 30:10:15) with BA and NAA at 1.0 mg 1-1 each was the most effective for plantlets growth in pot. In Vanda tessellata, suitable medium, explants and plant growth regulators (PGRS) were same as M. Orange for PLBS induction and NP with BA + NAA at 1.0 mg l-1 each was the best for PLBs multiplication. MS medium with 100 ml 1-1 PE and 1.0 g 1-1 charcoal was effective for in vitro growth of plantlets. In Aerides lawrenceae, NP medium with same explants and PGRs as M. Orange were suitable for PLBS induction. NP medium with 150 ml 1-1 BE and same medium with 20 g 1-1 maltose were effective for the multiplication of PLBS and the growth of plantlets in vitro, respectively. Fertilizer spray (3 g 1-1@ N:P:K= 30:20:10,) with BA + NAA at 0.5 mg 1-1 each was the most effective for the growth of plantlets in pot. These protocols might be helpful for commercial production of these orchids.