Arabidopsis rbcS genes are differentially regulated by light.

Individual members of the Arabidopsis thaliana ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit (rbcS) gene family are differentially regulated by light of different qualities. In 10-d-old etiolated seedlings, the expression of only three of the four genes is under inductive phytochrome control. rbcS mRNA levels reach a maximum (3- to 5-fold higher than the dark level) about 6 h after a red light pulse, but the rate of decay differs among the genes.

Long-Lasting Light Effects in Imbibed Kalanchoë blossfeldiana Seeds in the Presence of Gibberellic Acid.

Two brief red (R) irradiations, separated by 24 hours, given to Kalanchoë blossfeldiana Poelln. cv Feuerblüte seeds, made secondarily dormant by a prolonged dark incubation period on water and transferred to GA(3), induce very low germination. Some effect of these irradiations is preserved, however, during a long dark interval in fully imbibed seeds and greatly increases the germination induced by another brief R exposure.

Fluence-response curves and action spectra for the very low fluence and the low fluence response for the induction of kalanchoë seed germination.

Germination of Kalanchoë blossfeldiana Poelln. seeds is absolutely light-requiring. Germination of one seed is the result of one out of three reactions, viz.

Biphasic fluence-response curves for phytochrome-mediated kalanchoë seed germination : sensitization by gibberellic Acid.

The fluence-response curves for the effect of two red pulses separated by 24 hours on the germination of Kalanchoe blossfeldiana Poelln. cv Vesuv seeds, incubated on gibberellic acid (GA(3)) are biphasic for suboptimal concentrations. The response in the low fluence range corresponds with a classical red/far-red reversible phytochrome mediated reaction.