tailieunhanh - Advances in Applied Biotechnology Part 15

Tham khảo tài liệu 'advances in applied biotechnology part 15', khoa học tự nhiên, công nghệ sinh học phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Experimental Lichenology 269 mycobiont requires compounds secreted by the photobiont or associated bacteria. It has been found that the development of the mycobiont was quicker and more intense if 1 non-sterile tree bark was used as the substrate 2 the cultivating medium was conditioned by metabolites of the photobiont or bacteria 3 the spores were infected by bacteria Ahmadjian 1989 Yolando et al. 2002 Smirnov 2006 . Our results show that conditioning the media with simple metabolites after sterilization is inefficient compared to using native metabolites dialysis cultivation . Study of lichen morphogenesis A special place among experimental works in lichenology is occupied by the branch involving the study of lichen thallus morphogenesis and revealing the factors influencing this process. A number of studies have addressed the problem of inducing morphogenesis in callus cultures of soredia both in the laboratory and in the natural environment Stocker-Worgotter Turk 1988 Stocker-Worgotter Turk 1989 Yoshimura Yamamoto 1991 Armaleo 1991 Yoshimura et al. 1993 . Comparison of natural lichen thalli with those obtained by inducing morphogenesis in in vitro systems demonstrates their anatomical and morphological similarity the same layers are formed upper cortex in some species lower cortex photobiont layer medulla. One drawback of this approach is the fact that non-homogeneous material . in the shape and size of scales is often formed in the laboratory probably because of the heterogeneity of various thallus parts caused by the parasexual process Stocker-Worgotter Turk 1988 or by somatic variation Street 1977 Butenko 1999 . Lichens with different modes of reproduction sexual asexual and vegetative under laboratory conditions with morphogenesis induction undergo the same stages of development lag phase arachnoid phase prethallus and thallus Ahmadjian 1973a 1973b Ahmadjian Jacobs 1983 Stocker-Worgotter Turk 1989 Yoshimura et al. 1993 as in nature Ott 1988 . The .