Adventitious shoots

Bryant, J. P. (1981). Phytochemical deterrence of snowshoe hare browsing by adventitious shoots of four Alaskan trees. Science 113,889-890. 

Boughs of deciduous trees typically produce adventitious shoots when browsed or cut down. These include species of the genera Populus, Salix, Tilia, and others. In our experience. Eastern cottonwood (P. deltoides) and American basswood (T. americana) give good results in terms of species similarities and differences. 

Efficient micropropagation of ipecac by adventitious shoot formation on internode (Method II)... 

Adventitious shoots formed in liquid medium and their alkaloids... 

The alkaloid contents of adventitious shoots in liquid medium were quantified by HPLC, Fig. (20). They produced alkaloids, especially cephaeline (0.4 - 0.6% dry weight), and there was no obvious difference in alkaloid contents among different concentrations of BA. This result indicates that ipecac shoots, formed on intemodal segments, have the capabilities of alkaloid biosynthesis. 

Fig. (20). Alkaloid contents in the adventitious shoots formed on intemodal segments, grown in liquid medium. Culture conditions were the same as in Fig. (19).

Fig. (21). Shoot proliferation in a fermenter a RDF (rotating drum fermenter) b adventitious shoots formed on intemodal segments cultured in an RDF...

Histological observations of adventitious shoot initials were performed by light mieroscopy and seanning electron microscopy (SEM) as follows. The internodal segments were fixed in Camoy s fluid... 

Theoretical number of ipecac to be micropropagated through adventitious shoot formation on internode and its application... 

There has been a demand for the development of cryopreservation methods for plant cells to avoid the troublesome maintenance of tissue cultures and the danger of microbial contamination. The most successful method for cryopreservation of plant cells reported so far has been the freezing of callus cultures or shoot tips [36, 37]. As the system here enables us to obtain sufficient initial shoot materials, its potential practical application to cryopreservation is in progress. In addition, the system of adventitious shoot formation might be a promising tool to investigate relationship between morphogenesis (shoot formation) and alkaloid biosynthesis. 

Improved micropropagation of ipecac through adventitious shoot formation on cultured root segments (Method III)... 

Micropropagation systems mentioned previously (Method I and Method II) require two different cultural steps, shoot multiplication and rooting. In the course of tissue culture studies of ipecac, adventitious shoot formation on cultured root had been incidentally found. Therefore, one step micropropagation system of ipecac was established through adventitious shoot formation on the cultured root [14]. 

Adventitious shoot formation on cultured root segments... 

Light microscopy and SEM were undertaken by the same method described in section 1.4.4. Cross section and SEM of adventitious shoots formed on the cultured root segments are shown in Fig. (25). These observation indicate that shoots were directly formed on the surface of cultured root segments without callus formation as those on the intemode segments. Therefore, the reason for variation in alkaloid contents (Table 11) may not be attributable to the callus formation. 

Adventitious shoot formation occurred when the roots were cultured onto auxin-free medium as mentioned above. Since the decrease of auxin levels seemed to be important for the adventitious shoot formation, the influences of auxin inhibitors on shoot formation on the cultured root segments were investigated. The auxin polar transport inhibitor, 2,3,... 

Polar transport of endogenous lAA was indispensable for the adventitious shoot formation on the cultured roots of ipecac. This micropropagation system can be easily applied to other woody species if detailed mechanism will be elucidated. 

Plant biotechnological application is promising as an alternative source for the production of pharmaceuticals. Clonal propagation of ipecac plants through shoot meristem culture [section 1.1] adventitious shoot formation on in vitro intemodal segment [section 1.4] and on cultured... 

In the preliminary experiment for MAFF clone 1 in liquid culture using a 100 ml flask, the ratio of UC to DT tended to increase with the increase of rotation rates. In the case of Cephaelis ipecacuanha (section 1.4.2), the frequency of adventitious shoot formation on intemodal segments was 83.7% when cultured in a RDF, whereas it is below 30% when cultured in an airlift type fermenter. The inhibition of shoot formation might be related with the hydrodynamic stress produced by aeration and/or rotation. Therefore, a RDF was chosen for P. somniferum cultures because the production of DT seemed to be associated with the codeine formation. Since moderate growth and alkaloid accumulation and proliferation of DT were observed in WP medium, DT was cultured using WP liquid medium. 

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