Studies On The In Vitro Conservation Techniques Of Three Species Of Pteridophyte

The objective of this research is to establish a technique as to find out a best way for preserving ferns efficiently. The materials are spore, prathollium, sporophyte of Adiantum reniforme L.vax.sinese; Adiantum capillus-veneris and Platycerium wallichii . In order to discover the effect of different pretreatment at different temperature on fern's physiological and genetic characterization, they had been preserved at the temperature of 4C.-72Cand -196C and different time for 1 day, 7days and 30 days respectively. The content of this research includes : the surival rate and germination of spore after preserved by low temperature; the activity and defferentiation of prothallium after preserved by low temperature; the survival rate of sporophyte after preserved by low temperature, and the micropropagation system for Adiantum capillus-veneris and Platycerium wallichii after they are preserved by low temperature. The results as follow:1.The viability of three species of fern's spore is kept at the temperature of 4C and -72C decreased when the preservation time prolonged; at-196C, it changed slightly. Two method of thawing didn't produce obviously effect on the survival rate of the ferns spore.2 When prothallium of Adiantum capillus-veneris and Platycerium wallichii had been kept at temperature of 4 Cand 72 C for different times, their survival rate decreased rapidly when freezing time prolonged. And under cryopreserved by vitrification, the survival ratio can get to a high level and didn't decreased with time elapsed. The quickly thawing method has benifited to the survival of the prothallium.3.Preserved in liquid nitrogen(LN),the survival ratio of sporophyte can reach more than 80%, and rapid thawing has a dramatic effect on it. Same as prothallium, preservated in 4 C and 72C, the survival rate of sporophyte decreased rapidly when freezing time prolonged4. The techniques system suitable to cryopreservation for Pteridophyte are as follows: The longtime preservation for spore should keep in LN, and short-time preservation should keep at 4C and the time would better less than 1 month. And to spore, the two thawing method can be used. The way of preservation of prothallium and sporophyte is same to spore , but the way of rapid thawing is better for getting a higher viability. It need a treatment process for the materials cryopreserved before they are plunged into cryopreservation equipment. First they should be loaded with cryoprotectant for 20 to 30 mins, and were exposed to PVS1(PVS2) at 0C for 50 to 60 mins, then followed by changing the solution with fresh PVS1(PVS2), finally were immersed into LN directly, and kept for different time.5 To Platycehum wallichii . after cryopreserved, the optimal medium of spore germination was suggested as 1/2MS medium supplemented with 0.5% GA. And MS medium supplemented with 0.1 %BA and 0.01% NAA is the best medium for prothallium incremention. For sporophyte regeneration and rooting, the best medium is 1/2MS medium.6 To Adiantum capillus-veneris, after cryopreservation the optimal medium of spore germination was suggested as 1/2MS medium supplemented with 0.5% GA. And MS medium supplemented with 0.1 %BA and 0.05% NAA is the best medium for prothallium increment. For sporophyte regeneration and rooting, the best medium is 1/2MS medium.