Effect of cold, heat and chemical stresses on the induction of androgenesis in lisianthus (Eustoma grandiflorum)

Several methods are available to produce haploid plants. One of the most efficient methods is especially microspore culture. Stress as a triggering factor is essential for embryogenesis induction in microspores. In the first experiment، the effect of different thermal stresses including cold treatments and heat stress and the control were evaluated. In the second experiment، the effect of 2،4-D and in the third experiment effect of PEG-4000 were studied. In addition، some other stresses including high medium pH، ethanol and high speed of centrifugation were also tested. Results showed that cold pretreatment (4˚C for 1 day) and heat stress (35˚C for 2 days) induced cell divisions. Among stresses tested، heat stress (35˚C for 1 day) was the most efficient one for induction of and rogenesis. The best concentration of 2،4-D for and rogenesis induction was 25 mg/l that induced the highest ratio of multicellular structures. The most effective cellular changes were observed when PEG in 10 percent density was applied. The pH (6. 5 and 7) induced the initiation of microspore cellular divisions and creation of multi-cellular structures. The high speed centrifugation caused only swelling of microspores.