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Meristems are small groups of
cells from which all parts of the plant arise. By maintaining a
collection of meristem cells throughout their lives, plants are able
to adapt their form to their environment to a much greater degree
than animals, whose adult body plan is established early in the
embryo. Meristems determine plant architecture by dynamically
integrating environmental and genetic cues to determine numbers and
positions of leaves, branches, and flowers, the course of root
growth, the time to maturation, and the course of flower and fruit
development. The long-term goal of understanding meristem function
is to more directly control plant architecture for improvement of
agricultural yield in a wide variety of diverse growth conditions.
Meristem activities possess a
complexity that belies their small size and simple appearance. This
complexity is reflected in signaling events that take place among
meristem cells and between the meristem and other parts of the
plant. Meristems receive signals conferring information about light
conditions, temperature, water content, nutrient content, and other
environmental factors from roots and leaves, and use this
information to make developmental decisions. At the same time,
different parts of the meristem must coordinate their activities to
properly allocate cells to primordia and stem growth while
maintaining a pool of cells for future growth. We are interested in
elucidating the nature of these signals.
Current Research:
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Figure 1. An
optical section through an Arabidopsis mature embryo stained
with the nuclear dye propidium iodide. The densely staining
nuclei in the circles indicate the location of the shoot
meristem (top) and root meristem (bottom); these meristems are
the ultimate source of all adult plant structures.
Click the image to view full size. |
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Figure 2. A. Though simple in appearance, meristems have complex
superimposed functional zones that must coordinate their actions
in conjunction with environmental and genetic cues to produce
plant structures and maintain meristem structure. Shown here is
an Arabidopsis shoot apical meristem (SAM) that is initiating
floral meristems on its flanks. B. Shoot meristems have a
central zone (CZ) of slowly dividing cells, which acts to
replenish cells in the peripheral zone (PZ) and Rib zone (Rib)
that are lost to flower primordium initiation and stem
production. C. Superimposed on this are clonally distinct layers
(L1 or epidermal, L2, and L3 or corpus), between which cell
division is coordinated to maintain meristem shape.
Click the image to view full size. |
Dr. Mark
Running
Donald Danforth Plant Science Center
975 North Warson
Road
St. Louis, MO 63132 USA
314-587-1641
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