In vitro propagation and analysis of mixotrophic potential to improve survival rate of Dolichandra unguis-cati under ex vitro conditions

Abstract

An efficient and reproducible protocol for in vitro propagation of Dolichandraunguis-cati has been established for the first time from nodal segments. In order to enhance survival rate under ex vitro conditions, photosynthetic potential of in vitro grown plantlets was also studied through JIP test based analysis of polyphasic OJIP chlorophyll a fluorescence OJIP transients, density of active reaction centers, light harvesting efficiency, electron transfer rate, dissipation energy, maximum quantum yield of primary PSII photochemistry and photosynthetic performance index. The best morphogenetic in term of explants response (92.2 %), shoot number (3.43 ± 0.07) and shoot length (4.7 ± 0.31 cm) was obtained on Murashige and Skoog medium supplemented with 0.5 mg l−1 BAP and 1.0 mg l−1 TDZ. The shoots exhibited high frequency rhizogenesis on half strength medium augmented with 2.0 mg l−1 IAA. In vitro plantlets developed highest rate of photosynthesis on day 18 after the initiation of rhizogenesis. High survival rate (96.16%) under ex vitro conditions was observed when in vitro plantlets having high photosynthetic efficiency (Fv/Fm > 0.75) were subjected to hardening and acclimatization process. Plantlets with reduced photosynthetic performance exhibited low survival rate under natural conditions. The developed in vitro protocol will be useful for genetic improvement and multiplication of D. unguis-cati. The results of this study also show that photosynthetic screening of in vitro developed plantlets is highly essential after the rhizogenesis process to achieve higher survival rate under field conditions.