Sucrose availability on the aerial part of the plant promotes morphogenesis and flowering of Arabidopsis in the dark

Abstract

SummaryConditions to promote dark morphogenesis and¯ower-ing in Arabidopsis have previously been limited to liquid cultures and to a few laboratory ecotypes. We have obtained development and¯owering of Arabidopsis plants under complete darkness by growing them on vertical Petri dishes containing solid agar medium with sucrose. Under these conditions, all the ecotypes tested were able to develop, giving rise to etiolated plants that¯owered after producing a certain number of leaves. Dark-grown plants showed similarities with phytochrome-de®cient mutants and were different from de-etiolated or constitutive photomorphogenesis mutants such as det and cop. Late-and early-¯owering ecotypes, showing large differences in¯owering time and leaf number under long days,¯owered with a similar number of leaves when grown in the dark. Rapid dark¯owering of late-¯owering ecotypes was not an effect of darkness but the result of the interaction between dark and sucrose availability at the aerial part of the plant, since sucrose also had an effect when plants were grown in the light. Gibberellin-de®cient and insensitive mutants were delayed in the initiation of owers in the dark, indicating a role for these hormones in¯owering promotion in the dark. The late-¯owering phenotype of mutants at different loci of the autonomous and long-day-dependent¯owering induction pathways was rescued in dark growth conditions. However, the late-¯owering phenotype of ft and fwa mutants was not rescued by sucrose either in the dark or in the light, suggesting a different role for these genes in¯owering induction.

Arabidopsis thaliana life without phytochromes

“…Thus, seedling development is the second transition blocked by phytochrome absence in Arabidopsis, unless this restriction is bypassed by the activation of cryptochromes. Arabidopsis plants can even flower in full darkness if the leaves are in contact with sucrose, but the latter provides a morphogenic cue (32).…”

“…We avoided the contact of sucrose with the aerial tissues (Fig. S4) because the latter provides a morphogenic signal sufficient to complete the life cycle in the dark (32). In some seedlings, sucrose promoted root growth and some additional development of aerial tissues.…”

Transitioning to the Next Phase: The Role of Sugar Signaling throughout the Plant Life Cycle

“…For example, it was observed that Suc concentration in leaf exudate increases in response to an inductive long day (Corbesier et al, 1998), and Suc supply can promote flowering of Arabidopsis plants even in the dark (Roldán et al, 1999). It was therefore discussed if Suc may act as florigen (Corbesier and Coupland, 2006).…”

High concentrations of sucrose induce overwintering bud formation in gentian plantlets cultured in vitro

“…Therefore, we attempted to develop alternative methods to induce IOWB formation. In plantlet culture, sugars are one of the most important factors as energy sources and regulators of morphogenesis (Roldan et al 1999). We compared sugar contents between shoots and IOWBs: the concentrations of glucose and fructose were lower in IOWBs than in shoots, whereas sucrose accumulated in IOWBs to levels that were approximately threefold higher than in shoots (Figure 1).…”