Kennzeichnung der Bildung und Alterung von Wurzeln in Callus-und Organ-Kulturen von Daucus carota durch die Aktivit�t der Glutamatdehydrogenase

Abstract

In callus tissues of Daucus carota rhizogenesis was influenced by addition to the cultures of solutions with different kinetin concentrations (0-0.1-0.5-2 mg/l) and a constant auxin content (1 mg/l). In these cultures the specific activity of glutamate-dehydrogenase (E.C. 1.4.1.2.), aspartate-aminotransferase (E.C. 2.6.1.1.), isocitrate-dehydrogenase (E.C. 1.1.1.42) and of acid phosphatase (E.C. 3.1.3.2.) was determined. Before root initiation can be seen morphologically in tissues grown on low kinetin concentrations, the specific activity of glutamate-dehydrogenase increases to more than three times the level found in cultures with no subsequent root initiation, whereas the specific activity of the other three enzymes changes far less. Total soluble protein measured as percentage of fresh weight remains nearly the same in all callus cultures. The activity of the same enzymes was measured in liquid grown roots of Daucus carota during a period of ageing of 130 days. During this time, the specific activity of glutamate-dehydrogenase is reduced to 1/10 of the value found in growing roots, whereas the activity of the other three enzymes is reduced only to 1/2 or to 1/3 of this value. Therefore, the state of senescence and the capacity for further growth can be characterized by the specific activity of the glutamate-dehydrogenase in the roots. The changes in the specific activity of glutamate-dehydrogenase in callus tissue and in the roots do not depend on inhibitory substances in the cell-free extracts.

Nitrate, Ammonium and Kinetin Effects on Growth and Enzyme Activities of Paul's Scarlet Rose Callus

“…EDTA inhibition at lower ammonium concentrations remains a possibility to be studied in the present system. The kinetin inhibition of glutamate dehydrogenase activity noted by Werner and Gogolin (1970) in carrot tissue cultures was not observed in the callus of PSR in the range of kinetin concentrations used.…”

“…Kinetin inhibition of glutamate dehydrogenase in carrot tissue cultures was observed by Werner and Gogolin (1970). Since kinetin stimulates protein synthesis and retards its degradation (Trewavas 1972), it might be expected to infiuence directly or indirectly the ammonium assimilation reactions in plants.…”