Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Physiologia plantarum
43 (1978), S. 0
ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The effect of cytokinins was studied on the incorporation of 14C-labelled precursors into the nucleic acid fraction of protoplasts isolated from callus or roots of Brassica campestris. Protoplasts from callus and roots took up 14C-uridine from the incubation medium and incorporated this precursor into the ribonucleic acid fraction during the experimental period of 16 h. Low concentrations of kinetin (10−8-5 × 10−6M) did not stimulate the incorporation, and kinetin inhibited this process at higher concentrations (5 × 10−5M). This result led to an investigation on the uptake of cytokinins by protoplasts of roots. In contrast to a rapid uptake of radio-actively labelled adenine and uridine. protoplasts from roots took up only small amounts of labelled kinetin. zeatin, zeatin riboside and zeatin nucleotides from the incubation medium.Root sections took up far more adenine and kinetin than protoplasts from roots. The ratio between the amount of kinetin taken up and applied was much higher for the sections than for protoplasts, indicating that intact root cells took up kinetin far more rapidly than protoplasts. It is suggested that the plasmalemma and cell wall play an essential role in the uptake of cytokinins or that the differences in the uptake rates are related to differences between the rates of metabolism of cytokinins in root sections and in protoplasts.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1399-3054.1978.tb01582.x
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