the effect of orchid immature embryos age on asymbiotic germination frequency by optimizingplant growth regulators

Abstract 
Objective
Orchids seeds are so small, lacking nutrients and barely germinate in natural condition. For germinating in natural conditions, should associatie with fungi, especially mycorrhizal fungi. Drawing on the tissue culture technique and meeting all necessary growth and development conditions, the limitations can be overcome.
 
Materials and Methods
After being surfaced cleaned, the capsules containing seeds were placed in 1% Teepol solution as a disinfectant and wetting agent for 20 minutes to completely remove pathogens; then were washed and placed under laminar air flow, disinfected with HgCl₂ 0.2 for 10 minutes, Bavistin and Streptomycin each one 0.03% for 5 minutes in a entirely sterile environment. All the culture media were simultaneously ready and the seeds were uniformly inoculated in a totally sterilized environment and incubated. 
 
Results
The percentage and germination rate were affected by seed age and plant growth regulators. The formation of spherule and chlorophyll synthesis were highest in the third stage of seed culture. Based on the type of treatment, the formation, development and differentiation of protocorm were observed between 43-76 days after culture, which was statistically significant at 1% compared to control.
 
Conclusions
Considering the data analysis results, the success rate from the germination stage to the differentiation of protocorm in orchid seeds is mostly different based on seed age in each spices and cultivars, the type of plant growth regulators used, The ratio and composition of the two types of auxin and the ratio of auxin to cytokinin and vice versa are different. Therefore, it is necessary that new complementary experiments be done for each spices and cultivars based on the difference in the time taken from pollination to embryo ripening.