ZYGOTIC EMBRYO CRYOPRESERVATION OF Calamus vattayila RENUKA, AN ENDANGERED RATTAN PALM OF INDIA, AS INFLUENCED BY SEED MATURITY.

BACKGROUND

Calamus vattayila Renuka is an endemic and endangered rattan palm of the Western Ghats, India where the development of a protocol for cryopreservation is important for their ex situ conservation in gene banks.

OBJECTIVE

The objective of the study is to devise an efficient protocol for cryopreservation of the species, comparing the relative efficiency of seeds and zygotic embryos as storage material.

MATERIALS AND METHODS

Mature seeds extracted from ripened fruits were subjected to cryopreservation through a simple dehydration method and zygotic embryos isolated from seeds of three different maturity stages were cryopreserved through an encapsulation-dehydration method.

RESULTS

The mature seeds did not tolerate desiccation and freezing but the isolated zygotic embryos tolerated both desiccation and freezing. Embryos isolated from immature, partially mature and mature seeds harvested respectively after 160-170, 210-220 and 250-260 days after flowering possessed 82 - 86% moisture content (m.c.) and tolerated desiccation down to 9% m.c. with 80% viability. Embryos from immature seeds gave a maximum 63+/-26% regeneration after LN exposure, which is nearly equal to the corresponding desiccated control (73%). LN tolerance declined with maturity of seeds with a maximum of 49% of embryos from partially mature seeds and 25% from mature seeds subjected to LN exposure showing post-freeze recovery and regeneration.

CONCLUSION

Although immature seeds collected during February-March were recalcitrant (desiccation sensitivity), their embryos tolerated cryopreservation through encapsulation-dehydration better than embryos isolated from more mature seeds.