Photoautotrophic micropropagation for cost-effective and successful clonal multiplication of woody fruit crops.

摘要

A photoautotrophic (sugar free) micropropagation (PAM) system possesses many advantages offsetting the drawbacks of conventional heterotrophic micropropagation which are mainly low growth rate, physiological and morphological disorders, poor rooting and low percent survival during ex vitro acclimatization and field transfer. Nodal segments of Japanese plum (Prunus salicina Lindl.) cultivar 'Methley' collected in July from a mature (25-year-old) mother plant showed 72% establishment in Murashige and Skoog (MS) medium supplemented with BA (0.5 mg/L), IBA (0.05 mg/L IBA) and tapioca as gelling material. Heterotrophic MS medium (HM) modified with high nutrients, tapioca and hormones was found to be the best for quick and early shoot proliferation showing 1:19.83 multiplication ratio after 150 days of implantation. Though rooting in proliferated shoots was better in HM with agar, it was preferable to use PAM for root induction as the PAM-grown pre-hardened plants showed 100% survival with quick growth response within 2 days of transplanting in soil. There was an increase of 2.17 times in cuticular wax content and 1.08 times in total chlorophyll content after 21 days of acclimatization in PAM-grown plantlets vis-a-vis heterotrophically grown plantlets. The proposed protocol suggests that use of tapioca as gelling agent and introduction of photoautotrophy during root induction will lead to cost reduction and 100% success in field survival to combat major bottlenecks in micropropagation of woody species.