Abstract
In leaves of Arabidopsis thaliana, decreased cell proliferation activity often triggers excessive cell enlargement, a phenomenon that we named compensation. We have isolated and characterized five mutants (fugu1-fugu5) that exhibit compensation. The cotyledon of fugu5 is oblong on rockwool and exhibits strong compensation. However, we found that morphological phenotype of fugu5 is recovered in vitro cultures. Histological analysis showed that in fugu5 cotyledons grown in vitro, the number of cells recovered to wild type levels. On the other hand, compensated cell enlargement in fugu5 was completely cancelled. Analysis of fugu5 phenotype on MS-medium with different supplements revealed that sucrose was necessary and sufficient for fugu5 phenotype recovery. Similar concentrations of sorbitol did not affect fugu5 phenotype. Analysis of the effect of other sugars, such as glucose, fructose, and non-metabolizable analog on fugu5 phenotype is now underway. Based on these results, the mode of action of sucrose will be discussed.
