In Vitro Conservation Of Golden Camellia Germplasm

While tissue culture technology has often been utilized in propagation of rare and endangered plants, the effects of long-term culture on the viability and genetic stability of explants are still poorly known. In this study, the changes in 21 micropropagated explants of Golden Camellia, maintained for over 11 years in modified MS medium supplemented with 2.5 mg.L^-1 (11 μmol/L) N⁶-benzyladenine (BA) and 1.5 mg.L^-1 (8 μmol/L) indole-3-acetic acid (IAA) and 500 mg.L_-1 lactalbumin hydrolysate, were evaluated. There was no observable sign of variation to be found in the first 3 years. During this time, dissection, chromosome counting, analysis on karyotype and isozyme indicated the tissue culture seedling was true to wild type. 3 years later, some of the preserved materials began to stop budding and faded and even die away. The deterioration is diverse among species. Camellia longruiensis was exhausted after culture in vitro for 5 years. Camellia flavida follow its lead half a year later. But C. ptilosperma, C. longgangensis, C. longzhouensis didn't wither, although their vitalities somewhat declined, they were capable of regenerating a little new shoots after 11 years' duration in vitro culture. The author also notes that the shearing method and selection strategy, which might induce the loss of vigorous meristem region, play an important role in the degeneration. Meanwhile the author discusses the correlation between culture condition and deterioration, and the influence of regeneration pathway.It's a conventional wisdom now that conventional in vitro culture can only serve as a rapid propagation protocol, as for short to middle-term conservation purpose are concerned, adding special chemicals such as growth retardant, silver nitrate, and special culture condition is a must, while liquid nitrogen is necessary for long-term cryopreservation.We didn't take any special measures to the Golden Camellia in vitro gene pool to prolong the intervals for subculture, and the culture condition was the same as common protocol, based on this ground and we come to the conclusion that the degeneration of explants is closely related to the characteristics of species, the age of explants, the loss of vigorous meristem region during subculture and the environment of culture.Conventional in vitro conservation of rare and endangered plants doesn't make sense.According to the long experience of in vitro conservation of Golden Camellia, we come up with the notion of rapid propagation value, suggesting that most plants are not worth our while. The first and foremost is to find the right species to deal with if you want to make profits from tissue culture. The characters of desirable species often possess are presented.We believe that conservation in situ first, then ex situ, conservation in vitro is the last resort for rare and endangered plants.