ISSN:
1432-2048
Keywords:
Auxin (xylem differentiation)
;
Cytokinin (xylem differentiation)
;
mRNA induction (phenylalanine ammonia-lyase)
;
Phenylalanine ammonia-lyase (mRNA induction)
;
Xylem differentiation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Expression of the phenylalanine ammonialyase (PAL) gene during tracheary-element differentiation was studied in mesophyll cell-suspension cultures ofZinnia elegans. Dose-response curves of benzyladenine (BA) and α-naphthaleneacetic acid (NAA) were obtained for the cultures in order to achieve the highest percentage of differentiation. The optimal concentrations of BA and NAA were 0.1 mg·l-1 and 0.06 mg·l-1, respectively, which normally stimulated about 40% differentiation by 96 h of culture. The effects of the same ratio but different amounts of BA and NAA on tracheary-element formation have been tested and the results indicate that the absolute amounts of BA and NAA rather than the ratio of them were important for tracheary-element formation in theZinnia cultures. The cells when cultured in the presence of 0.001 mg·l-1 of BA and 0.06 mg·l-1 of NAA expanded and divided but did not differentiate. The level of PAL activity, synthesis of PAL protein and the level of PAL mRNA peaked during 72 to 96 h when lignin was actively deposited. This indicated that the PAL gene was temporally and preferentially expressed in association with the lignification during tracheary-element differentiation and thus it can be regarded as a molecular marker for the process.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02341036
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