Aleurone
The cereal aleurone cell is well established
as a model system for studying hormonal regulation of plant cells. The
aleurone of the barley grain is a digestive tissue that secretes hydrolases
that mobilize endosperm reserves during germination. The synthesis and
secretion of these hydrolases (principally a-amylases) is under hormonal
regulation. Gibberellin (GA) stimulates a-amylase synthesis and secretion,
whereas abscisic acid (ABA) reverses this effect. The site of perception
of these hormones in the aleurone cell is now tentatively assigned to
the plasma membrane. However, the signal transduction events leading
from the receptor to the coordination of the complex events that make
up and regulate the secretory activity of these cells are still poorly
understood. It is these events that we are interested in studying.
We are studying the role(s) of cytoplasmic regulators such as
-
cytoplasmic calcium levels
- Phospholipases
-
G-proteins
-
protein kinases
in
the control of these cells in response to GA and ABA.
For example
to the right is a computer analyzed microsocope Image of the signal-related
calcium levels in a barley aleurone cell as it responds to the hormone
gibberellic acid.
More images and movies
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