Gene

Cotyledon

Cytokinin

Biology

Phytochrome

Biochemistry

Botany

Far-red

Auxin

Darkness

Chemistry

Zeatin

Red light

Germination

Journal of Plant Physiology

The type of cytokinins evaluated and identified when seeds were germinated with red light and with red light followed by far-red light were the same as those observed when germination was carried out in darkness. Red light affected the behaviour of endogenous cytokinins. An increase was observed in the appearance of free bases in the cotyledons paralleled by an increase in the transport of these substances from the axis to the cotyledon. Lower levels of free bases and glycosides were found in the embryonic axis accompanied by a delay in the transformation of zeatin and zeatin riboside into their dihydro forms. Under this kind of treatment a transport of dihydro forms from the cotyledon to the embryonic axis was also observed which is absent in darkness. Far-red light applied after red light treatment reversed the effects of the latter wich indicates the involvement of phytochrome in the processes responsible for the accumulation and transport of cytokinins. However, in cotyledons, far-red light does not reverse the advance caused by red light in the transformation of zeatin and zeatin riboside into their dihydro forms.

Effects of Red light and Far-red light on the Variation and Transport of Endogenous Cytokinins during the Germination of Chick-pea seeds