Cytokinins determine arabidopsis root meristem size and root growth rate by controlling cell proliferation rather than cell differantationтезисы докладаТезисы
Дата последнего поиска статьи во внешних источниках: 8 февраля 2017 г.
Аннотация:The transition of meristematic cells to elongation is needed for maintenance of the root growth rate
since the duration of the root cell elongation is very short. The rate of cell transition to
elongation (differentiation) is regulated by two groups of independent processes. The first ones regulate
the life-span of cells in meristem – the duration of the period when cells located
at various distances from the root tip reach the basal boundary of meristem and begin to elongate. The
seconds one regulate the rate of the cell proliferation during the life-span of cells in meristem. Transzeatin
slows down the root growth rate and the rate of the transition of meristematic cells to elongation
as a result of prolongation of mitotic cycles. The life-span of cells in meristem does not change. The
number of meristematic cells in one file decreases but it is the result of the inhibition of cell proliferation
but not the acceleration of the cell transition to elongation (differentiation). The roots of triple mutants
ipt3ipt5ipt7 in which cytokinin synthesis is slowed down grow at higher rate than control roots. The
number of meristematic cells in one file in these roots is greater than in roots of wild type. It is the result
of the higher rate of cell transition to elongation and the acceleration of cell proliferation. The life-span
of cells in meristem is shorter than in control roots. Analogical results were obtained for roots
of some cytokinin signaling mutants. Thus, slowing root growth, when treated with cytokinins, or
acceleration growth with reduction of the concentration of endogenous cytokinin
or weakening of their signaling are associated with changes in the duration of mitotic cycle.
Alyhough, there is a view that cytokinines regulate the cell transition to differentiation, and thereby
changing the rate of root growth and meristem size, our date rather showed that cytokinis affects the cell
cycle duration.
This work was partially supported by Grant of RFFI 15-04-02502.