Biology – Control and coordination in plants | e-Consult
Control and coordination in plants (1 questions)
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The closure of the Venus flytrap is a complex, coordinated process involving intricate cellular mechanisms and a precise sequence of events. It's not simply a passive folding of the leaves, but an active, controlled movement driven by changes in turgor pressure and cell wall properties.
Sequence of Events:
- Electrical Signal Propagation: Initial stimulation of a trigger hair generates an action potential that propagates through the sensory cells and then to the motor cells surrounding the lobes.
- Ion Channel Activation: The action potential triggers the opening of ion channels in the motor cell membranes, leading to an influx of ions (including potassium and chloride). This influx contributes to the change in turgor pressure.
- Changes in Turgor Pressure: The influx of ions causes water to enter the motor cells, increasing their turgor pressure. This increased pressure makes the cells more rigid.
- Cell Wall Modification: Auxin, transported to the motor cells, causes changes in the cell wall composition. This makes the cell walls less elastic and more rigid, further contributing to the increase in turgor pressure.
- Coordination and Movement: The increased turgor pressure in the motor cells causes them to swell and exert force on the adjacent cells. This coordinated swelling and force generation leads to the lobes rapidly closing towards each other. The specific arrangement of the cell walls and the way they interact creates the snapping motion.
- Mechanical Latching Mechanism: Once the lobes close, interlocking spines on the outer edges of the lobes prevent the trap from reopening prematurely. This latching mechanism ensures that the prey is securely captured.
Cellular Mechanisms: The entire process relies on the coordinated activity of various cellular mechanisms, including changes in ion permeability, turgor pressure regulation, and cell wall modification. The precise timing and coordination of these events are crucial for the efficient capture of prey.