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.

Fertilizing ability of cryopreserved pollinia of Luisia macrantha, an endemic orchid of Western Ghats.

A successful protocol for long-term preservation of pollinia of Luisia macrantha Blatter and McCann., an endemic and endangered orchid of Western Ghats has been devised through different pollen cryopreservation methods and by confirming fertilizing ability. Pollinia subjected to 0-30 min dehydration at 27 +/- 67 percent in desiccated controls and 54 percent in LN treated samples. The treated pollinia retained fertilizing ability, giving 100 percent fruit set upon sib-mating. Pollinia dried under charged silica gel for 120 min gave 51 - 52 percent pollen germination, in LN treated and desiccated control samples. Exposure to vitrification solution (PVS2) was optimized at 10 min to achieve 57 percent and 56 percent germination in control and LN treated samples, respectively. These pollinia exhibited 51 percent pollen germination after 668 days storage in LN. Cryopreserved pollinia (10 min PVS2) used for hybridization with Vanda tessellata gave 87 percent fruit set and 21 percent viable seeds. The viable seeds germinated and developed into healthy seedlings. Thus cryopreservation has been proved useful for the successful storage of L. macrantha germplasm and their utilization in breeding.